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A90 Series Correspondence Lessons

PART H

Plain Bearings

Lesson A9019 Bronze/Glacier Bearings Lesson A9020 Bearlon/Orkot Bearings Lesson A9021 Rod Ends/Ball Bushings

PART H – Plain Bearings Series 90 Training

PART H Plain Bearings

Lesson A9019

Correspondence Course LESSON A9019

Plain Bearings – Bronze and Glacier

LESSON A9019 Series 90 Training

Table of Contents Bronze Bushings 4 Glacier Bearings 10 Bronze Bushing Size Charts 19 Glacier Running Clearance 11 Bronze End Use 8 Glacier Structural Bearings 14 Centrifugal Casting 6 Load Capacity 8 Chemical Analysis - Bronze 4 LG2 Bronze Bushing Weight Chart 22 Continuous Casting 6 Machined Bronze Bushings 8 DU Glacier Bearings 10 Permaglide Type P1 15 DU & DX Glacier Strip 14 Permaglide Type P2 16 DX Glacier Bearings 12 Plain Bearings 3 FB Part Numbers 19 PV Factor 11 Finished Size 7 Selecting Glacier 11 Fitting Practices - Bronze 9 Sintalite Bearings 9

Structured Training Plan

This lesson is the nineteenth of a series of Correspondence lessons in the BSC Structured Training Plan.

Objectives

The objectives of this lesson are to acquaint students with Bronze, Glacier and Rod Ends so that they may understand the part number system and be able to advise customers on these products.

Pre-requisites

Completion of Correspondence Lessons A9001 - A9018, A9049.

Methods

Achievement of the objectives is by presentation of lessons in an 'On-Line' or Correspondence Course format. The lessons in a Correspondence Course style are conducted for internal students in a lecture situation.

Assessment

A formal test is provided with this lesson.

LESSON A9019 – Plain Bearings (Bronze and Glacier) Series 90 Training page 2


PLAIN BEARINGS Introduction

Plain (sleeve) bearings have been in use since the "invention of the wheel", which is put by historians at 4000BC. In the lessons on Friction and Bearing Basics, we saw how plain bearings developed and briefly touched on their uses in automotive engines. In fact, there are many applications where Plain bearings fulfill the end use requirement and are the obvious first selection. Plain bearings, as a group, could be described as "Formed pieces of material with a smooth bore used to support a shaft" to hold the shaft in relation to the other parts of the machinery and accept the involved radial loads (perpendicular to the shaft).

Many are in the form of a one piece bush, some are split into two halves with a top piece and a bottom piece, and others have a flange at the end to take thrust load or to locate the shaft end wise.

During this century, many new materials have been developed which either complement, or have replaced, traditional plain bearing materials. Some of these new materials do not even require lubricant in order to work. Bearing Service stocks the following Plain bearings and/or materials: BRONZE - Bushes and Bushing Material GLACIER - Bushes and Stripes PERMAGLIDE - Bushings and washers MOLY(LUBRON) - Bushing Material ORKOT - Bushing Material and Sheets In this lesson, we will be concentrating on the first two - Bronze and Glacier. These are both metal based bearings whereas the other two are non-metal bearings.


BRONZE BUSHING Bronze is one of the most popular materials for making "sleeve" bearings. It has been around for at least 3500 years and is certainly a most ancient material having been in use by bronze-age man. Bronze is an alloy which has Copper as the base metal, to which is added Tin, Lead, Phosphorus, Zinc and Nickel in various proportions. Australia is a major producer of Copper along with USA, Chile, Canada, Zambia and Katunga. The copper is produced from ore by a process which involves firstly concentrating it by the use of a wet process which removes the earthy waste. The resulting material is then heated to molten stage where iron and silicon float to the top to produce a slag. The molten copper or 'matte' is separated and processed further to produce crude copper. Further refining improves the quality to an acceptable level. Our bronze is sourced from McKechnie Metals Pty Ltd (Admax) and we stock both pre-machined bushes and 12" lengths of bushing. Longer lengths are available from factory stock, up to 10" for continuously cast material.

The bronze which we carry in stock is an all purpose bronze, but is made to special specification for use as bearings. Admax state the specifications as: Conforming to AS 1565 Alloy C83600 (1985) Equivalent to BS 1400 LG2-C U.S.A SAE 40 Chemical analysis shows us the proportion of different types of base metal in the standard bronze carried in stock. As you can see from the table below, the main component metal is Copper.

Chemical Analysis Symbol % COPPER Cu 85

TIN Sn 5 ZINC Zn 5

LEAD Pb 5 PHOS. P .05

Mechanical Properties:


Ultimate Tensile Strength 18 Tons/Sq.inch (28.3 Kg/Sq.mm) Yield Stress 10 Tons/Sq.inch (15.7 Kg/Sq.mm) Elongation 25% Hardness (Brinell No.) 80 It should be noted that the figures given above are averages, as each batch varies slightly from other batches. When the various metals are added to the copper base, each has a special purpose and the correct percentages of each are important if a good bearing bronze is to be the end result. The purposes are: Tin To create hardness and facilitate casting.

Lead To increase plasticity and machinability. To act as a metallic lubricant. To compensate for slight misalignment at installation.

Phosphorus To eliminate abrasive oxides and to add the alloy's hardness.

Zinc Act as a de-oxidant, like the action of phosphorus, and improve the lead distribution in the alloy. Also to increase ductility and tensile strength.

Bronze up to, and including 8" outside diameter is CONTINUOUSLY CAST. Sizes above this to 30" outside diameter are CENTRIFUGALLY CAST. Above 30" outside diameter the bronze is SAND CAST. Rod from 8" to 12" is CHILL CAST. Refer to Appendix 1 to view the Fraser Bronze Bushing Size Charts in Imperial and Metric size range.


PRINCIPLE OF CONTINUOUS CASTING

Molten bronze is poured from a furnace into a crucible which is cemented to the neck of a graphite die. The lower half of which is water cooled, and the metal sets in this section, and is withdrawn through two sets of rollers. A flying saw mounted below the roller cuts the bar to the required length.

Continuous cast rod has greatly improved physical properties as compared with normal sand-cast material. Because of the bottom pouring conditions and rapid cooling that the metal receives in the cooling zone, inclusions are completely eliminated, grain structure is tight and even giving excellent pressure tightness qualities. Tensile strength and wearing qualities are increased by up to 35%.

Various shapes can be made with this casting process such as: Hexagonal rods and Angle and Flat strips but there is a minimum material weight of 1-1/2 ton.

PRINCIPLE OF CENTRIFUGAL CASTING

Molten bronze is poured from the furnace ladle into a pilot ladle which directs the stream of liquid bronze into a horizontal spinning die. This die determines the O.D. of the casting produced, and the wall charged with the correct amount of molten bronze, the die continues spinning for a predetermined period to produce dense, close grained bronze. On completion of the spinning process, the die end is removed, the bronze withdrawn and inspected.


Both hollow and solid bronze is sold, stocked and ordered by its FINISHED SIZE. The finished size is produced by the customer during the machining of the stock size to suit his requirements. This means that the foundry leaves a suitable machining allowance on the diameter of the bronze pieces as below: Continuous cast: - To 2" O.D. has 1/16" oversize on O.D. and approx. 1/16" undersized on I.D. - To 6" O.D. has 1/16" oversize on O.D. and approx. 1/8" undersized on I.D. Centrifugally spun: - Has 1/8" oversize on O.D. and 1/8" undersized on I.D. Some Features of Bronze:

• Has a high load carrying capacity.

• When the film of lubricant breaks down or is ruptured, the shaft and bearing bore make contact and friction occurs. Friction leads to wear and temperature rise which is the cause of many bearing failures.

• Requires a running clearance to compensate for thermal expansion and to permit an oil film.

• Selection of a suitable length for a bearing generally starts by the customer indicating the shaft diameter he requires the bearing to suit. Depending on the type of service, the variable factors are LOAD, SPEED, LUBRICANT, and TEMPERATURE.

• An accepted ‘general-normal’ engineering clearance is a MINIMUM of approx. 0.001" for each one (1) inch shaft diameter. Other than normal medium speeds and loads require separate consideration to determine a suitable bearing clearance.

• The length of the bearing bush can range from 3/4 of the shaft diameter to 3 times the shaft diameter.

• The design is generally arranged to provide for the dissipation of heat generated in the bearing.

• For normal duty the length can be between one to one (the same as the shaft diameter) to one and a half times the shaft diameter. With shock loading and vibration present the bearing bush length should be increased to at least double the shaft diameter.

• Perfect lubrication will reduce build-up of heat by providing a continuous film of either oil or grease between the sliding surfaces.

• Misalignment of a pair of bronze bushes leads to OVER HEATING because the high loading at the end of the bush results in lubrication failure. The probable maximum misalignment that can be accommodated is in the order of 0.001" per inch of the bearing centres.


End Use Applications Besides general purpose bearings other applications include: Hydraulic Ram Components, Crank Gears, Valve Seats, Side Valves, Rock Drill parts, Crusher Bearings, Hose Nozzles, Irrigation Equipment, Rollers, Washers, Wear Rings to name but a few. MACHINE BRONZE BUSHES To compliment our range of bronze bushing, we also stock a range of machined Bronze Bushes which are fully surface finished and ready to install and put into service as supplied. Small bushes may require the bore to be reamed. The bushes are manufactured from continuously cast bronze by our supplier Admax and have the same chemical composition as the Bronze Bushing. Tolerances: Imperial Metric Inside Diameter -.0005 -0.01 +.0015 +0.04 Outside Diameter +.002 +0.06 -.004 +0.10 Length +.010 +0.25 -.010 -0.25 The same principles apply for the selection and use of machined Bronze Bushes as outlined in the section on Bronze Bushing. The sizes range from 5/16" shaft diameter to 2-1/2" shaft diameter with various wall thicknesses, to give a selection of outside diameters, and come in a number of lengths. The Imperial part numbers all start with the prefix "FB" and bear no relationship to the size of the bush. For example part number FB1 measures 5/16" I.D., 7/16" O.D. and 1/2" long. Part number FB1073 measures 5/16" I.D., 3" O.D. and 4" long. Metric part numbers are based on the size, thus FD10X12X20 is 10mm ID by 12mm OD by 20MM long. To view the Fraser Bronze Alloy LG2 Bronze Bushing Weight Charts, see Appendix 2. Load Capacity Load Capacity is generally based on the projected area of the bronze bush and is the number of square millimetres of area figured by multiplying the shaft diameter by the length of the bush. Variable factors which must be used to select a machined bronze bush for a job are thus: - Temperature in the working area - Temperature rise in service - Type and quantity of lubricant fed to the bearing bush - Rotation Speed - Load in KG's on the projected area of the bearing bush. - Quality of the shaft surface finish.


The customer generally uses his practical experience or may refer to his engineering hand books and make the calculations to enable him to select a suitable machined bronze bush for his job. Because of the number of variable factors involved in the selection of a suitable size bronze bush that are unknown to our sales staff, we seldom recommend a size to our customers. Stock Range Our current price list shows the listing of all bronze bushings carried in stock. We do not promote special non-stock sizes unless the quantities are in the hundreds off for one size as special tooling would be required and the cost of this would have to be spread over the cost of each unit. When only a few non standard items are required we promote our 12 inch lengths of stock bearing bronze. Fitting Practice With a rotating shaft and a stationary bronze bush, you will have noticed that the tolerance of the I.D. will give clearance with the normal undersized of the shaft diameter. The clearance is necessary to provide a space to hold lubricant. There are two alternative methods of holding the O.D. of the bronze bush securely in the housing. 1) To press fit the bush into a normal housing clearance, as the O.D. of the machined bush is made oversize on it's normal diameter. 2) To machine out the housing to have an average clearance of .002" on the bush and seat it with a drop of 601 Loctite coated thinly on the outside of the bush. NOTE- use 242 Loctite if easy removal of the bush is required. SINTALITE Bearings SINTALITE porous bronze bearings are made from tin (10%) and copper (90%) and contain no lead, zinc, graphite or other low cost materials. The manufacturers describe their product as having a metallic sponge type construction containing 30% oil by volume. This provides an unbroken oil film on the bearing surface, just where it is required. The oil provides a cushioned operation, giving outstanding performance on shock loads and ensuring quiet trouble free operation with no sticking, gumming or scoring. The bearings are supplied fully oil impregnated and ready for assembly. They would normally be pressed into the housing using an arbour press on a shouldered fitting pin or similar tool. SINTALITE bearings are available in both a sleeve type and a flanged type. Thrust bearings are also available in the form of either a washer or disk.


GLACIER BEARINGS The Glacier range of Bearings and Materials comprise of types DU and DX and are considered an important member of the Plain Bearings group we stock and sell for the reasons below:

• High potential sales volume due to range of existing and future applications in Road, Rail and Aircraft transport equipment, Textile machinery, Agricultural equipment, Electrical equipment, General Engineering, Mechanical Handling and Packaging Equipment.

• As a Plain Bearing material it has been time and job proven as suitable for situations where lubrication is undesirable, impractical or unreliable.

• Suitable for a wide range of both load and sliding velocities as a journal bearing bush or in the form of a thrust washer in both "DRY" and "WET" operations.

• Glacier "DU" has a wide range of working temperature from minus 200 degrees C (minus 325 degrees F) to plus 280 degrees C (plus 525 degrees F).

Friction is low and wear resistance is high due to the "DU" material which uses Lead filled PTFE (fluon) on Bronze as the bearing surface. PTFE is well known for Anti-adhesives properties as "always slip" never stick. Glacier DU bearings

How is Glacier "DU" Made? Glacier is made up from three bonded layers. The backing strip is copper plated steel. To this is sintered the middle layer of porous bronze with the pores solidly filled with a mixture of PTFE and Lead in the proportions about 80% - 20%. The surface layer is about 0.001" thick of the same PTFE - Lead mixture. Experience has shown that in use under working conditions, a film of the PTFE mixture of the "DU" surface is transferred to the opposing rubbing surface and this film as well as a thin surface layer on the "DU" is maintained throughout the working life of the bearing.


How Are "DU" Bushes Made? Under a power press the split Glacier Bushes are formed and then accurately sized in a die on a mandrel to close manufacturing tolerances so that all produced are interchangeable. The outside diameter at the ends are tin-plated or copper-plated to protect them from rusting in mildly corrosive surroundings. Selecting the Right Size As you will understand from previous papers on Plain Bearings, our company does not encourage our salesman to recommend a particular size of any Plain Bearings for a particular customer job without first making a calculation. The calculation is detailed in the designer's handbook and is associated with a suitable "PV" factor which is lbs load multiplied by velocity on the rubbing surfaces in feet per minute.

This "PV" is varied by using factors associated with the working conditions and the shafting material, hardness and its surfaces finish. Best results are obtained by using a hardened face of about 58 Rc. on the "DU" surface and with steel shafts ground to about 16 micro inches CLA scale and with Cast Iron surface in contact, use a ground finish of micro inches. The life of the bearing can be further extended by a final polish to the sliding surface in the areas which contact the "DU" bearings. Recommended Running Clearance To provide a suitable bearing clearance it is important that the journal diameter be ground to the sizes shown in the catalogue with the high and low size tolerances indicated. The housing bore is given in the catalogue with similar high and low tolerances on the required sizes for the machinist. Part Number Codes for "DU" Glacier Bearings The code is simple to follow as the part numbers show the bush bore size in 1/16" units followed by the name "DU" and then the bush length in 1/16' units in size. A full listing is given in appendix 3. Examples in inch sizes: 08 DU 14 = 1/2" dia X 7/8" long 16 DU 24 = 1" dia X 1-1/2" long 40 DU 24 = 2-1/2" dia X 1-1/2" long In the metric series the part numbers follow a similar system of showing the mm size in the code. The prefix "MB" for Metric Bush is followed by the bush bore diameter and the bush length in mm and the suffix DU to show the material. Examples in metric sizes: MB 1220 DU = 12mm dia. x 20mm long MB 2515 DU = 25mm dia. x 15mm long


Glacier "DU" Thrust Washers These washers are used to provide positive shaft location and to accept thrust loading and have an inside diameter to provide clearance over the shaft diameter the parts can not be identified by measurements without the catalogue. Alternatively, by comparison with parts in the sales bins. The parts are branded with their numbers on most but many are not stamped with their part number. Examples in the inch and metric sizes:

• DU 06 Using 1/16" units equal 3/8" shaft and has an inside diameter 0.015"/0.500". • DU 16 suits a 1" shaft and has an inside diameter 1.135"/22.00mm. • WC 20 DU suits 20mm shaft and has an inside diameter 22.25mm/22.00mm. • WC 12 DU suits 12mm shaft and has an inside diameter of 14.25mm/14.00mm

DX Pre-Lubricated Bearings

In the "DX" range of bearings bushes and thrust washers, Glacier have developed a generally similar construction method to the DU type. The steel backing provides a rigid support for the layers of porous bronze and the Acetal Resin Polymer which is also called by the well known trade name Delrin. You will recall that we refer to Glacier "DU" as a dry bearing as they are most often fitted and used without any lubrication and sometimes in contact with a liquid which can act as lubrication and control temperature rise. The Glacier "DX" is a pre-lubricated type. This does not mean that it is supplied already lubricated but rather that the lubricating grease is applied prior to fitting on the shaft. In operation, the initial pre- lubrication grease is transferred around the indentations by the sliding action of the rotating shaft and lasts for a very considerable time without a re-lube. Thus the indentations act as a reservoir. The code number of Glacier "DX" bushes in inch sizes use 1/16" units of size for the shaft size and length. A Full listing is given in Appendix 4. Metric DX bushes are available in two types - a pre-finished type and a machineable type. Bearing service stocks are mainly of the pre-finished type and these are identified by the prefix PM (pre-machined). The machineable type (MB) have a thicker coating on the ID allowing reaming to very close tolerances. Note that the imperial dimensioned Glacier are only available in machineable type.


Examples in Imperial sizes: 12 DX 08 3/4" shaft x 1/2" long. 20 DX 16 1-1/4" shaft x 1" long. Examples in metric sizes: Machineable type MB 1525 DX 15mm shaft x 25mm long. MB 2530 DX 25mm shaft x 30mm long. Pre-machined type PM 1420 DX 14mm shaft x 20mm long PM 2415 DX 24mm shaft x 15mm long Finished Size: Some idea of the differences in dimensions of Glacier bushes can be seen from the following table:

MB (mm)

PM (mm)

DU (mm)

Nominal Bore 14 14 14

Journal Diameter 13.950 13.923

14.000 13.973

13.984 13.966

Machined Bore 14.000 14.018

14.040 14.110

Housing Diameter 16.000 16.018

16.000 16.018

16.000 16.018

Thrust Washers Glacier make a range of both inch and metric "DX" Thrust Washers and the part numbers follow the "DU" system. Examples: DX 16 suits a 1" shaft (with 1/16" units of diameter.) WC 25 suits 25mm shaft. Bronze Backing in "DU" AND "DX" When the quantity to be made at the factory is sufficient to be an economical run. In place of the steel backing on both "DU" and "DX" glacier material, rolled Bronze can be used. The change in the material part descriptions to be added "B" for bronze to the code thus: DU (B) and DX (B). When corrosion resistance is required and where rolled bronze would be more suitable than the steel backings, this is the material specified.


Glacier "DU" and "DX" Strip We stock and sell Glacier "DU" and "DX" inch pieces 18" long by 4" wide and it is exactly the same material as used in the bearings (see appendix 3). Engineers and Machine makers or repairers cut up the strips to make the facing surfaces to accept sliding motion for the guide ways of reciprocating equipment. Due to its ability to run dry, good low friction properties and availability from stock there is s general demand for "DU" strip. "DX" strip is less popular although we do carry a few sizes in stock. The thickness of the 18" x 4" strips of the material is associated with a range of group numbers thus: Group Number Type Thickness 0 DU 0.028in 0.07mm 1 DU 0.044in 1.10mm 2 DU 0.059in 1.49mm 3 DU 0.075in 1.88mm 4 DU 0.091in 2.28mm 5 DU 0.120in 3.03mm B DX 0.0480in 1.03mm C DX 0.0630in 1.52mm D DX 0.0783in 2.02mm E DX 0.0937in 2.53mm Structural Bearings by Glacier Glacier make an extensive range of standard and special bearings to accept the movement in Bridges due to expansion and contraction from changes in temperature. They use either "DU(B)" material or a Fibre Glass filled PTFE (Teflon) pad as these will permit the movement under loading from 50 to 3000 tons per bearing. The sliding face on the Glacier surface is usually polished stainless steel. The top and bottom base plates are made from high tensile S.G. cast iron or steel and some of the different series will accept a tilting motion, rotating movement and other actions due to the various loadings placed on the bridge girders and beams, etc.


PERMAGLIDE Permaglide is a plain bushing material similar to the Glacier DX range, and is supplied by INA. There are two types known as P1 and P2. The features of the two types are listed below.

Permaglide7 Plain Bearing Material P1

Features

• Maintenance Free • Suitable for:

- dry running - rotary movement - oscillating movement - linear movement with short stroke lengths • Good sliding characteristics - no stick-slip • Low coefficient of friction • Low wear • High chemical resistance • Does not tend to weld to metal • Largely resistant to swelling - does not absorb water • Hydrodynamic operation possible.

Variants

P10 with steel backing

P11 with bronze backing, therefore

• largely corrosion-resistant • very good thermal conductivity • antimagnetic


Basic Information

The chemical resistance depends on the chemical characteristics of the individual layers. In general, Permaglide7 P1 is resistant to water, alcohols, glycols and many mineral oils. Permaglide7 P1 is designed for dry running, i.e. there is no lubricant to protect the mating surface. Rust cannot form between the sliding material and mating surface due to the running-in layer or sliding surface comprising PTFE and Pb. Permaglide7 P1 can be operated under hydrodynamic conditions.

Electrical Conductivity

The electrical conductivity of new bearings may be lower because the running-in layer is still present. The bronze layer is partially exposed after the running-in process, thus improving the electrical conductivity. The electrical resistance is dependent on the size of the contact surface area.

Lubrication

Permaglide7 P1 contains dry lubricants and therefore does not need lubrication. It can be used in fluid media in certain applications. The improved heat dissipation in this case can significantly increase the operating life.

Part Numbering

Metric part numbers begin with the letters PAP and relate to the size and type. A PAP 1220 P10 is type P 10 and has a shaft size of 12 mm and is 20 mm long. This applies to the P2 type bearings described below.

Imperial part numbers have a similar format but begin with PAPZ. The dimensions are in 1/16th inch increments so a PAPZ 1612P10 is type P10 with a shaft size of 1 inch and a length of 3/4 inch.

Permaglide7 Plain Bearing Material P2

Features

• Low Maintenance • Suitable for:

- rotating and - oscillating movements

• Long re-lubrication intervals • Low wear • Good resistance to edge stress • Good damping behaviour • Good resistance to shock loads


Variants

P20

• with lubrication pockets • ready-to-fit

P21*, available by agreement

• with lubrication pockets • with machining allowance

P22*, available by agreement

• without lubrication pockets • with machining allowance

P23, available by agreement

• without lubricaiton pockets • ready-to-fit

* The sliding layer is on average 0.15mm thicker than in the case of P20. It can therefore be machined subsequently. Misalignment inaccuracies can therefore be compensated or internal clearances with tighter tolerances can be achieved.

Basic Information

The chemical resistance depends on the chemical characteristics of the individual layers. In general, Permaglide7 P2 is resistant to water, alcohols, glycols and many mineral oils.

Rust cannot form between the sliding material and mating surface due to the sliding layer comprising PVDF, PTFE Pb and the lubricant.

Permaglide7 P22 and P23 (without lubrication pockets) can be operated under hydrodynamic conditions.

Lubrication

Low-maintenance Permaglide7 P2 must be lubricated with grease or fluid.

Highly suitable lubricating greases used is Lithium soap with a mineral oil base. Grease additives such as molybdenum disulphide and zinc sulphide are unfavourable since they increase wear.


A9019 - Questionnaire

Name: Branch (eg QAA) Employee No (from Payslip): Date:

Plain Bearings - Bronze and Glacier

Questions Answers

Q1. What minerals are added to copper to produce LG2 bearing material? A. Zinc

B. Tin

C. Iron

D. Lead

E. Phosphorus

F. Aluminium

Q2. What advantages does continuous cast bronze have over sand cast? A. Inclusions are completely

eliminated

B. Grain structure is tight

C. No casting material is present

D. Can be made to exact size.

Q3. Why is tin added to the material - what purpose does it serve? A. To increase ductility and tensile

strength.

B. To act as a metallic lubricant.

C. To create hardness and facilitate casting

Q4. Why is Bronze rod cast oversize? A. Traditional practice

B. To allow for machining

C. To allow for manufacturing margins

Q5. How is the part number FB100 related to the bronze bush size? A. 100mm outside diameter

B. No relationship to size

C. 1 inch outside diameter

Q6. What is the tin content of SINTALITE Bearing material? A. 10%

B. 20%

C. 25%


A9019 – Questionnaire (cont.)



Q7. What material is used to coat the bearing surface of Glacier DU bearings?

A. PTFE/Lead Mix

B. PTFE

C. Lead

Q8. What is the working temperature range for Glacier DU bushes? A. -200 degrees C to +280 degrees C

B. -100 degrees C to + 180 degrees C

C. - 50 degrees C to + 120 degrees C

Q9. What are the Dimensions of a Glacier 08 DU 16 bearing? A. 1/4 inch diameter by 1/2 inch long

B. 1/2 inch diameter by 1 inch long

C. 1 inch diameter by 1/2 inch long

Q10. What is the part number for a DU thrust washer to suit a 3/4 inch shaft?

A. DU12

B. DU 6

C. DU 3/4

Q11. DX series bearings are described as "pre-lubricated". What does this mean?

A. Supplied with Lubricant already in bearing

B. Lubricating grease is applied prior to fitting on the shaft

Q12. What are the dimensions of a Glacier MB 1220 DX? A. 12 mm ID x 20 mm long

B. 3/4 inch ID x 1-1/4 inch long

C. 20mm ID x 12 mm long

Q13. What does the group number indicate in connection with Glacier DU strip?

A. Length

B. Thickness

C. Quality





Q14. List one application for Glacier Structural Bearings. A. Roller Skates

B. Machine Tools

C. Bridges

Q15. Which type of Permaglide bearing would you recommend for an application where linear movement was in play and an antimagnetic bearing was essential?

A. P10

B. P11

C. P20

Q16 What are the dimensions of a Permaglide PAPZ 1012 P10? A. 10mm Shaft x 12 mm Length

B. 1 inch shaft x 1.25 inch length

C. 5/8 Shaft x 3/4 width


Lesson A9020


Plain Bearings – BEARLON and ORKOT


Table of Contents Abbreviations - Plastics 17 Orkot 21 All about Plastics 3 Orkot, Properties 21 Bearlon Introduction 3 Performance of Plastics 4 BEARLON Polyurethane 14 - 6 Cast Nylon 6 5 PTFE 15 - 6 and BEARLON 66 extruded Nylons 6 RALLOY® - GSM Cast Nylon 6 MoS2 filled 5 - HDPE 11 - LF oil-filled nylons 6 - Polypropylene 11 - Properties 3 - PVC 13 - UH 7 - UHMWPE BR1000 9 Crystalline and Amorphous 3 - UHMWPE 8000 10 LEXAN® Polycarbonate sheet 9 TECAFORM AH® Acetal 12 Lubricant for Orkot 22 TECAPET® PET 13 Molecular Weight 3 Thermosets 4 Nomenclature 16 TL Orkot 21 Ordering - Plastics 18 TLG Orkot 21 TLM Orkot 21


This lesson is the twentieth of a series of Correspondence lessons in the BSC Structured Training Plan.

Objectives

The objectives of this lesson are to teach students the part numbering system and applications for Bearlon and Orkot bearing material so that they may be able to advise customers on these products.

Pre-requisites


Methods


Assessment


LESSON A9020 – Plain Bearings (Bearlon and Orkot) Series 90 Training page 2


Plain Bearings - BEARLON and ORKOT

Introduction

In lesson 19, we discussed two types of plain bearings - Bronze and Glacier. The products covered by this lesson are the non-metal plain bearings - BEARLON and ORKOT.

BEARLON

The Engineering Plastics supplied by Mulford Engineering Plastics is carried under the trade name of BEARLON.

ALL ABOUT PLASTICS Plastics are sometimes known as Polymers, but the real building blocks of plastics are Monomers, which are combined in various types of chains.

Homopolymers - chains of one type of monomer e.g. Polyethylene Copolymers – chains of two different monomers Terpolymers – chains of three monomers e.g. ABS

Different Polymers can also be combined into Alloys – can you think of one?

MOLECULAR WEIGHT The length of the chains of molecules in Polymers makes a big difference to how plastics behave. Plastics with very high molecular weights are less “plastic” – less easy to form or mould, e.g. UHMWPE has a molecular weight over 3,000,000. Crystalline and Amorphous The way the chains of molecules in Polymers combine also makes a big difference to how plastics behave. Plastics in which the chains group and closely align are called semi-crystalline, and these plastics tend to have higher heat resistance, e.g. Nylon, Acetal, UHMWPE, and HDPE. Plastics where the chains of molecules are like cooked spaghetti in a bowl are called Amorphous. They tend to be transparent with a lower, but gradual softening under temperature, e.g. Acrylic, Polycarbonate. In Engineering Applications, we tend to prefer semi-crystalline plastics in applications which are load-bearing and high wear.


Thermosets One of the advantages of plastics is that they can be formed into a shape (like a rod or a sheet) and then formed again into some new shape using pressure, heat or both. They are thermoplastics. Thermosets, such as phenolics and melamine (Tufnol, Micarta) can only be formed once, after which they must be machined (cut, milled, routed) to a new shape. Performance of Plastics The real-life performance of a plastic material can be predicted if we know the conditions under which it will operate.

Temperature - at what operating temperatures and for how long? Stress - what force or load will be applied, how often, and for what period of time? Impact – will there be sudden loading, or collision forces? Strain - in which way will the plastic be stressed, inducing a change in shape under

stress? When we look at how plastics will perform, we can measure typical performance under a range of conditions:

Tensile Strength / Elongation – pulling or stretching forces Compressive Strength – force of load / weight Shear Strength - surface forces in motion Flexural Strength – bending Torsional Strength – twisting forces

Plastics perform differently under different conditions such as temperature, moisture and time. They tend to creep, or continue to change in shape under load over time.


Plain Bearings – BEARLON

Product Information Standard Engineering Plastics

BEARLON 6 Cast Nylon 6

Description Nylon 6 G cast Natural (opaque yellow)

Key Properties BEARLON 6 is a stress-relieved cast nylon which is suitable for large volume and thin-walled machined parts.

Very easily machined High toughness even when dry High resistance to stress cracking Wear resistant, good sliding properties, shock absorbing Resistant to many oils, greases, diesel and petrol Nylon absorbs moisture at ~4-6%V

Product Range

Rods Diameters Std Lengths

50.0mm to 250.0mm 2000mm

Other Sheet Rods Tubes

1.00mm to 200 mm 4mm to 800mm OD 25mm to 710mm

Applications Mechanical engineering Bearings and rollers, e.g. conveyors Equipment components: textile, printing, packaging, agricultural

machinery Gears, couplings Building equipment

Also available: TECAST M® Charcoal grey

BEARLON GSM Cast Nylon 6 MoS2 filled

Description Nylon 6 G cast MoS2 filled Black

Key Properties BEARLON 6M is a stress-relieved cast nylon to which MoS2 has been added to increase the degree of crystallinity. Higher strengths are thus achieved without any loss in toughness. BEARLON 6M has higher impact strength than BEARLON 6. Key properties as for BEARLON 6 with increased surface hardness Not electrically insulating UV and weather resistant

Product Range Rods Diameters Std Lengths

50.0mm to 200.0mm 2000mm

Other Sheet Rods Tubes

1.00mm to 200 mm 4mm to 800mm OD 25mm to 710mm


Applications Mechanical engineering Bearings and rollers, e.g. conveyors Equipment components: textile, printing, packaging, agricultural

machinery Gears, couplings Building equipment

Also available: TECAST M® Charcoal grey

BEARLON 6 and BEARLON 66 extruded Nylons

Description Nylon 6 and Nylon 66 Extruded Natural (opaque yellow)

Key Properties Nylon 66 has higher mechanical strength, stiffness and toughness than extruded Nylon 6, although cast Nylon 6 has similar properties. BEARLON 66® has better heat, wear and creep resistance, but BEARLON 6® has better impact strength and mechanical damping properties. High mechanical strength and toughness Easily machined (BEARLON 66 is superior) Easily welded and bonded, good sliding properties Resistant to oils, greases, diesels, petrol


6.0mm to 70.0mm 3000mm

Other Sheet Tubes

0.5mm to 100 mm OD 25mm to 710mm

Applications Mechanical engineering, machined parts Gear wheels Friction bearings Conveyor screws Bushes Spindles Cam discs Rope pulleys Castors Impact plates Damping plates

Also available: Impact modified, Friction modified, Glass -filled and High heat versions

BEARLON LF oil-filled nylons

Description Nylon 6 oil-impregnated green Nylon 6 oil impregnated food grade white


Key properties

Nylon 6 rod with built-in oil lubrication Superior machinability and performance 45% lower coefficient of friction compared to standard nylon Reduced water absorption (maximum 4.5%) compared to standard cast nylons, promoting better dimensional stability Oil will not spin out, dry out or drain out under the harshest conditions Food grade is suitable for direct food contact Resistant to oils, greases, diesels, petrol

Product Range


40.0mm to 200.0mm 3000mm

Other Sheet Tubes

0.5mm to 100 mm OD 25mm to 710mm

Applications Gears Sleeves Bearings Bushes Sprockets Wear pads Sheaves Pulleys Guides Cams Feed Screws Wear rails Rollers Telescoping boom wear pads Star wheels Conveyor wheels Slipper blocks Wear rings Seals Scraper blades

BEARLON UH

Description Ultra-high Molecular Weight Polyethylene Natural

Key properties

Outstanding impact strength even at temperatures below -200 oC Excellent sliding wear and abrasion properties Low coefficient of friction-superior anti-stick properties Good chemical resistance Molecular weight > 5,000,000g/mol UV resistance poor Standard finish is planed, tolerance of ± 0.3mm Un -planed (press finish) sheet available on request

Product Range

Rods Diameters 20mm to 200mm

Other Also available in Sheets, Profiles and Wear Strips Custom cast upon request.


Applications UHMWPE 1000 is frequently used in high-wearing applications, from wear strips under conveyors to guide rails in bottling plants, or scraper blades on road rollers. UHMWPE sheets are used for lining bulk storage hoppers where low-friction, anti-stick and abrasion-resistant properties solve feed and wear problems.

Hopper linings Truck bed linings Chain guides and tensioners Screw conveyor linings Bottling, canning and packaging machinery Bulk handling materials

X-LUBE® Bushes

Description A range of self-lubricating bushes moulded in MoS2-filled Nylon

Key properties

X-LUBE® bushes are a cost effective alternative to metal or machined bearings and are precision moulded to close tolerances MoS2 additive reduces friction, improves wear resistance and reduces the need for lubricant Interference fit Available plain or shouldered Easy to install and maintain Good chemical resistance Excellent noise and vibration resistance Good insulation properties May be machined to finished dimensions

Product Range

Rods An extensive range of standard sizes is available in both metric and imperial sizes

Other Custom designed parts are available

Applications Door openers Cable drums Conveyor rollers Electrical insulators Agricultural, horticultural equipment Measuring equipment Meat processing Refrigerated cabinets Station isolators


LEXAN® Polycarbonate sheet

Description Clear polycarbonate sheet UV 2-sides Clear polycarbonate sheet mar-resistant 2 sides

Key properties LEXAN polycarbonate sheet is optically clear, impact, UV and fire resistant. Virtually unbreakable, it is an ideal material for safety and security glazing. UV2 has UV protection on both sides – 10 year warranty MR10 has a proprietary hard surface coating Both may be cut, routed, formed Can be cold -formed into gentle curves e.g. barrel vaults Follow glazing guidelines and always check chemical compatibility

Product Range Sheet Guage 1.0mm to 12.7mm

Other Ballistic Grades Rod and Tubes Thin films

Sheet - 9.5mm to 32.0mm

Textured sheet for low glare

Applications General purpose glazing Security screens Machine guards Specialty vehicle glazing Crane windows Appliance viewing panels Signs Bus shelters Lighting covers Riot shields

RALLOY® UHMWPE BR1000

Description Regenerated UHMWPE Black

Key properties UHMWPE BR grade is a special blend of ultrahigh molecular weight polyethylene which has been formulated for the Australian market Excellent UV resistance Exellent sliding wear and abrasion properties Low coefficient of friction - superior anti -stick properties Good chemical resistance Moplecular weight > 4,500,000g/mol Standard finish is planed, tolerance of ± 0.3mm Un-planed (press finish) sheet available on request

Product Range Sheet Gauge 8mm to 100mm

Sheet Sizes

1250mm x 3000mm


Applications With its very low coefficient of friction, Ralloy® BR1000 is the ideal liner material to prevent material hold-up and bridging in hoppers and silos.

Liners for bunkers and hoppers Under chain wear strips and machine guides Pump and valve components Star wheels

RALLOY® UHMWPE 8000

Description Ultra high molecular weight polyethylene with molecular weight >10mig/mol Blue Premium grade UHMWPE polymer which has been developed for use

Key properties Premium grade UHMWPE polymer which has been developed for use specifically in bulk material handling. It has an extremely low coefficient of friction which greatly assists in the bulk flow of cohesive or non free-flowing materials. High impact strength Excellent abrasion resistance Good chemical and corrosion resistance Standard finish is planed, tolerance of ± 0.3mm Un -planed (press finish) sheet available on request

Product Range Sheet Gauge 4mm to 25mm

Sheet Sizes

1250 x 3000

Applications Linings for storage bins Feeding chutes Hoppers Charging boxes Chain trough conveyors Vibrating chutes Self-unloading bulk carriers

Ralloy® UHMWPE 8000 is also available in anti-static, UV-protected and flame retardant grades, and with additional lubricating modifiers and glass-filled.


RALLOY® HDPE

Description Copolymer high density polyethylene Natural and Black

Key properties Lightweight and extremely tough Does not absorb water, and is resistant to odours and stains Easy to fabricate with standard woodworking tools May be machined and welded Natural is FDA approved for food contact Black is UV resistant High impact strength Good chemical and corrosion resistance

Product Range Sheet Gauges 1.5mm to 50mm

Sheet Sizes

1500mm x 3000mm 1000mm x 2000mm

Other – by special orderSheet 1.0mm to 100mm

Applications Chemical tanks Water tanks Linings for storage bins, silos and feeding chutes Wall linings Cutting boards Valves and pipes Bollards Dock fenders Rollers Washers Bushes

Ralloy® HDPE is also available in twin-colour sheet for playground and sign applications, and in marine board (UV stable, white).

RALLOY® Polypropylene

Description Homopolymer Polypropylene Grey - Beige

Key properties Highly resistant to chemicals across a wide range of acids, bases and solvents, even at elevated temperatures, Ralloy® Polypropylene is ideally suited to the manufacture of industrial containment tanks. Lightweight, with better physical strength than HDPE High surface hardness and gloss Negligible moisture absorption Easy to fabricate, form and weld High tensile strength and stiffness


Product Range Sheet Gauges 6.0mm to 30.0mm

Sheet sizes

1500mm x 3000mm

Other – by special order Sheet 1.0mm to 30.0mm

Applications Chemical tanks Structural tanks, acid tanks and plating modules Fittings for the chemical industry Laboratory equipment, fume hoods and ducts Chemical pipes Filter plates and frames Battery cases

TECAFORM AH® Acetal

Description Co-polymer Acetal (POM) White and Black

Key properties TECAFORM AH® Acetal is a hard engineering plastic which is highly suitable for automatic machining and precision mechanical parts. High tensile strength, hardness and impact resistance Low moisture absorption, good dimensional stability High resilience Physiologically inert – suitable for food contact Resistant to cleaning agents Good electrical insulating properties

Product Range Sheet Gauge Sheet sizes

6.0mm to 70.0mm 500mm x 3000mm


6.0mm to 200.0mm 3000mm

Other – by special order Sheet 1.0mm to 100mm Rods 3mm to 250mm Tubes OD 25mm to 505mm

Applications Heavily loaded bearings and roller, e.g. conveyors Gear wheels with small modules Bearings and gears with small tolerances Valve seats Snap-fit assemblies Insulating components in electrical and automotive engineering Cam followers Thrust washers Food technologies e.g. kneaders, rollers

Tool supports Also available as homo-polymer acetal TECAFORM AD® and in glass-filled, conductive, anti-static, and anti-microbial grades.


TECAPET® PET

Description Polyethylene terepthalate (Polyester) White (opaque)

Key properties TECAPET® is a rigid, hard-wearing material with a very low tendency to wear in damp environments. Wear resistant Low thermal expansion, high dimensional stability Suitable for parts with close tolerances Good dielectric properties, very good insulator FDA approved raw materials Easily machined, welded and bonded Good sliding properties

Product Range Sheet Gauges Sheet size

10.0mm to 50.0mm 500mm x 3000mm


10.0mm to 150.0mm 3000mm

Other – by special order Sheets 4.0mm to 100mm Rods 4mm to 200mm Tubes OD from 25mm to 300mm

Applications Transport and conveyor parts Food technology parts e.g. agitators, kneaders Plugs Friction plates Tool carriers Housing parts Rollers Plain bearings Gear wheels Insulators Seals

Also available: PBT modified for hardness TECADUR PBT® PBT and glass-filled TECADUR PBT GF30® Anti-microbial TECADUR PBT SAN®

RALLOY® PVC

Description PVC Grey


Key properties RALLOY® PVC has very high resistance to many chemicals including concentrated acids, alkalis and alcohols. Along with its excellent mechanical strength and ease of machining this makes RALLOY® PVC an ideal material for tanks and pipe fittings where chemicals are used.

Chemical resistance Excellent electrical insulation Easily bonded with solvent cement Low moisture absorption Good machining properties


6.0mm to 150.0mm 2000mm

Sheets 2.0mm to 15mm

Other – by special order Sheets 1.0mm to 100mm Rods 6.0mm to 350.0mm Welding Rods

Applications Rollers Spacers Pipe fittings Start wheels Pumps Insulators Chemical industry components

Polyurethane

Description Thermoset polyurethane elastomer Red PU40

Key properties Polyurethane is an extremely tough and durable material, available in a broad spectrum of different hardnesses, from eraser soft to golf ball hard. Remarkably resistant to abrasion and low temperature stiffening, and high load - bearing capacity. Outstanding abrasion resistance Good chemical resistance Harder grades can be machined Custom mouldings available

Product Range Sheet Gauge Sheet sizes

3.0mm to 50.0mm 1000mm x 1000 mm


10.0mm to 150.0mm 300mm

Other Custom parts, including tubes can be easily manufactured in a range of sizes and hardnesses.


Applications Industrial wheels Roller coatings Pump bushes and impellers Bearings and thrust pads Buffer rings and pads Gears and gear teeth Conveyor idlers and pulleys

PTFE

Description PTFE White

Key properties PTFE is a white, waxy-feeling industrial plastic with non-stick properties that are unmatched by any other plastic material. It is virtually inert and possesses useful electrical and mechanical properties. Lowest coefficient of friction (0.05 - 0.08) of any solid Upper temperature limit of 260°C Complete resistance to commonly-used chemicals May be modified by the introduction of fillers such as bronze, glass fibre, and carbon.

Product Range Sheet Gauge Sheet Sizes

5mm to 50.0mm 600mnm x 600mm

Rods Diameters td Lengths

3.0mm to 170.0mm 1000mm

Tubes OD from 20.0mm to 715.0mm

Applications Seals Gaskets Insulators Shrouds Ball valve seats Appliance parts


BSC Engineering Plastics Nomenclature

Plastic materials are identified by their;

MATERIAL TYPE e.g. Nylon, Acetal

SHAPE e.g. Sheet, Rod, Tube COLOUR SIZE

BSC will standardise product coding for plastic materials.

Each variation of material, shape, colour and size will have an abbreviation.

To create a product code, simply join the abbreviations for Product type, shape, colour and size - see table below. For example:

Nylon Oil-filled Rod Green 90mm NYLOFRODGRN90

Nylon Oil-filled Food Grade Sheet Beige 125mm

NYLFGSHTBGE125

Acetal Copolymer Custom / machined 310609

ACTLCPART310609


LIST OF ABBREVIATIONS FOR MATERIAL TYPE

Product Group Part Product Code Nylon 6 NYL6Nylon 66 NYL66Nylon Molybdenum-filled NYLMONylon Glass-filled NYLGFNylon Oil-filled NYLOFNylon Oil-filled Food Grade NYLFGNylon Solid lubricant NYLLX UHMWPE Standard grade UHPE1UHMWPE black repro UHPERUHMWPE Extra high wear UHPE8 Polypropylene POPR Acetal Copolymer ACTLCAcetal Homolymer ACTLH Polyurethane 60A hardness PU60Polyurethane 75A hardness PU75Polyurethane 80A hardness PU80Polyurethane 90A hardness PU90Polyurethane 95A hardness PU95Polyurethane 70DD hardness PU70DTooling TOOL PVC rigid PVC Polycarbonate Standard PCSTDPolycarbonate Abrasion resistant PCMRPolycarbonate Outdoor grade PC2UV Acrylic ACRY High Density Polyethylene HDPE Polyester PETP PEEK PEEKPTFE PTFEPVDF PVDF


List of abbreviations for product shape Rod Sheet Tube Custom/Machined

ROD SHT TBE PART*

* Plus a unique identifier for the job

List of abbreviations for common colours

Natural NAT Blue BLU

White WHT Clear CLR

Black BLK Opal OPL

Green GRN Orange OGE

Beige BGE Yellow YLW

Grey GRY Red RED

SIZES SHOULD ALWAYS BE IN METRIC

For sheet, specify thickness in mm For rod, specify diameter in mm For tube, specify OD and ID in mm

3mm 10mm 12.7mm 90mm 125mm 0.003mm Tube OD 90mm ID 50mm

3 10 12.7 90 125 0.003 9050

Ordering sizes – Units of measure (UOM)

In order to fit with BSC’s IT system, products can only be ordered in whole units.

Rod and Tube – the code will identify the diameter, the length of the rod is the unit of measure and must be in centimetres (cm = 10mm or 1/100th of a metre).

Sheet – the code will identify the thickness of sheet, the unit of measure will be piece or sheet, and in the product description, the dimensions of the sheet should be entered for each item. The dimensions may be in mm, cm or metres, but must be metric.


Plain Bearing - Bearlon - Sales Opportunities

LEXAN® MAR-RESISTANT POLYCARBONATE

FOR MACHINE GUARDS

Many sales opportunities exist in all areas of the industry for the use of Lexan Mar-Resistant Polycarbonate as Machine Guards. Here are some information provided by Milford plastics which highlights the features of this product.

Features:

Optical quality LEXAN® polycarbonate sheets -“water-clear” transparency

High impact strength

Dimensional stability at elevated temperatures

Flame resistant

FDA compliant

Light weight

Weatherable UV grade available

Formable

Also available in hard-coated MR grades to resist scuffs

Standard LEXAN® breakage warranty for 10 years

Large format sheets for all size barriers


SAFEGUARD PEOPLE AND ASSETS WITH THE ORIGINAL HARD-COATED POLYCARBONATE

In terms of where to look in developing applications for plastics, the team should be looking out for situations where the key properties of plastics are useful, or where there is a problem with traditional materials:

Eliminating metal-metal contact and the consequent wear and noise issues e.g. in conveying applications

Where chemical resistance or corrosion resistance would give better life e.g. where there are chemical clean-downs

Where Vibration or impact damping would be a benefit

To substitute for metals or non-FDA approved materials in food processing

Weight reduction – plastics are generally 5 times lighter than common metals such as stainless steel

Formable materials can be used to enhance design opportunities, to simplify parts

Where a transparent material would be useful

To provide electrical insulation properties e.g. as a separator or barrier material


Plain Bearing - ORKOT

"Orkot" is a laminated plastic material, made by impregnating cloths or fibres with thermosetting resins.

Originally developed for use as a roll-neck bearing material for steel rolling mills, the results were so excellent that they led to the development of "Orkot" as a general bearing material.

There are several grades of "Orkot", as can be seen in their catalogue, but as we only stock "TL" grade we shall only discuss this grade in this lesson.

The "TL" grade can be impregnated with either Graphite or Molybdenum Disulphide. If it is impregnated with graphite the material is call "TLG". and if impregnated with Molybdenum Disulphide it is called TLM.

These types can easily be identified on the shelf by their colour:

"TL" (Plain) White "TLG" (Graphite) Green "TLM" (Molybdenum Disulphide) Grey

TL grade is manufactured from a fine weave fabric and has excellent mechanical strength and exceptional dimensional stability when immersed in water, acids and chemical solutions.

PHYSICAL AND MECHANICAL PROPERTIES OF "ORKOT TL"

Tensile Strength 8 000 lb/sq.in. 563 kg/sq.cm. Compressive Strength 1. Flat Wise 50 000 lb/sq.in. 3 515 kg/sq.cm 2. Edge Wise 14 000 lb/sq.in. 985 kg/sq.cm. Flexural Strength 10 000 lb/sq.in 703 kg/sq.cm. Shear Strength 12 000 lb/sq.in. 844 lb/sq.cm Hardness Rockwell M 100 Density 1.25 gm/cc

Part Numbers

"Orkot" is available in rod, tube and flat sheet form. The part numbering system is based on the type and size in inches - thus:

TL 1 Rod is 1 inch solid rod in TL material TLG 4 x 2-1/4 is 4 inch OD by 2-1/4 inch ID tube in TLG material TLM 2 x 1-1/2 is. 2 inch OD x 1-1/2 inch id tube in TLM material. Orkot rod is supplied in 28 inch lengths as standard.


ADVANTAGES OF "ORKOT TL"

Chemical and Corrosion Resistance - "Orkot” does not corrode and is unaffected by many solvents, inorganic solutions, fats and weak acids. In fact water and chemical liquids often act as lubricants giving low co-efficient of friction.

"Orkot" is attacked by ketones, chlorinated solvents, strong alkalis and hot strong oxidising agents.

Very Low Moisture Absorption Rate - means that any increase in volume of ORKOT is restricted to 0.075% maximum.

Good Electrical Resistant - "Orkot" is an excellent insulating material. As bushes or washers, it is suitable for use in dynamos, electric motors, generators, etc. As flat laminate it can be used in heavy switchgear, transformers, insulating chassis and as a general constructional material. It is also non-magnetic and this property may often be exploited to advantage where interference with magnetic or electrical fields must be avoided.

Compressive Strength - "Orkot TL" has enormous compressive strength (see physical and mechanical properties) making it ideal for high load applications.

Natural Machining Properties - "Orkot TL" can be easily machined to fine finishes and tolerances.

Excellent Operating Temperature Range - "Orkot TL" has a wide operating temperature range as below.

Operating Temperature: - Maximum 130°C - Minimum -40°C - Maximum in water 100°C

Ability to Use a Wide Range of Lubricants - "Orkot' is resistant to most chemicals enabling many fluids being processed to act as the lubricant. The fibres in the surface of "Orkot" absorb slight amounts of lubricant and thus assist in the maintenance of a continuous film. Water is an excellent lubricant and tends to carry heat away from the bearing. Oils are at a disadvantage where heat is present because of the non-heat conducting nature of the material.

IMPORTANT NOTES ABOUT ORKOT

"Orkot" is susceptible to cutting wear when in contact with rough surfaces and consequently a fine machined finish, 32 CLA or better, should be given to mating metal parts. If this precaution is observed and lubrication is adequate the metal and the "orkot' will acquire highly polished surfaces in use thus prolonging life and reducing friction.

In common with other resin-bonded fabrics "Orkot” has low thermal conductivity and high co-efficient of thermal expansion. These factors must be taken into account in bearing designs particularly for high temperature applications.

"Orkot TLG" should not be used with stainless steel parts in contact with salt water as graphite will corrode stainless steel. This problem is well known to Marine Engineers and Naval Architects but care should be exercised when using TLG on stainless in city water which has a high saline content. The TLM grade is the one to use here.

The best lubricant is our BR2+ grease - Silicon greases must not be used with Orkot material.


A9020 - Questionnaire

Name: Branch (eg QAA)

Employee No (from Payslip):

Date:

Plain Bearings - BEARLON and Orkot

Questions Answers

Q1. The Engineering Plastic bearing material sold by BSC is called.. A. Nylon

B. Bearlon

C. Lubron

Q2. List 3 types of Monomer chains, described in the lesson as the real building blocks of plastics.

A. B. C.

Q3. Plastics where the chains of molecules are cooked like spaghetti in a bowl are called?

A. Crystallines

B. Amorphous

C. Morphous

Q4. What is the maximum water absorption of BEARLON LF oil-filled nylons?

A. 2.5%

B. 6.5%

C. 4.5%

Q5. Can PET plastic be easily bonded or welded? A. Yes

B. No

Q6. What is the maximum sheet size for PTFE sheet? A. 50 mm

B. 28 mm

C. 10 mm



Name: Branch (eg QAA)

Employee No (from Payslip):

Date:

Plain Bearings - BEARLON and Orkot

Q7. What is the part number for Clear Bearlon, Nylon Oil Filled, Food Grade Sheet, 5mm thick?

A. NYL66SCTNAT5

B. NYL66RODNAT05

C. NYLFGSCTCLR5

Q8. What lubricant would you recommend to be used with Orkot bearing material where heat is present?

A. Molykote BR2 Plus

B. Water

C. Thin Machine Oil

Q9 What grade of Orkot could be used on a Stainless steel shaft running in salt water?

A. TL

B. TLG

C. TLM

Q10. What is the part number for Molybdenum Disulphide impregnated Orkot tube size 3 inch OD by 2-1/2 inch ID?

A. TLM 3025

B. TLM 3X2-1/2

C. TLG 3X2-1/2


Lesson A9021


Rod Ends and Ball Bushings


Table of Contents Angular Contact 4 Ball Joints 9 Extended Inner Ring 5 Link Balls 8 Numbering System 5 Part Numbers, Metric 8 Part Numbers, Imperial 7 Rod Ends 6 Sealing 5 Spherical Plain Bearings 3 Stud Type Rod End 7 Thrust Type 5


This lesson is the twenty first of a series of Correspondence lessons in the BSC Structured Training Plan.

Objectives

The objective of this lesson is to explain ball bushings and rod ends to students so that they may be able to effectively handle customer’s requirements.

Pre-requisites


Methods


Assessment


LESSON A9021 – Rod Ends and Ball Bushings Series 90 Training page 2


Spherical Plain Bearings (Ball Bushings) The basic parts which make up a spherical plain bearing are the following:

1. Inner Ring 2. Outer ring

These bearings are often referred to in the trade as Ball Bushings. An offshoot of this type of bearing is the rod end which is basically a spherical plain bearing contained in a housing. It should be noted that spherical plain bearings and rod ends contain no rolling elements (Balls, Rollers). Movement is taken by the sliding action between the inner and outer ring, which have sliding contact surfaces. Because of this, spherical plain bearings and rod ends are only used where there are very slow rotation or oscillating (angular or not full rotation) movements. There are basically three different combinations of shifting surfaces in these bearings, which determines the application for which they are used. These are:

1. Hardened steel inner ring on Hardened steel outer ring. This type requires lubrication or maintenance.

2. Hardened steel inner ring on bronze outer ring - low maintenance type. 3. Chromium steel inner ring on PTFE or Teflon outer ring - Maintenance free type.

COMPONENTS We will now examine the basic parts of spherical plain bearings in more detail. 1) Inner Ring Imagine a slice taken from the centre of a solid steel ball, which then

has a hole drilled through the centre. This is the appearance of the inner ring of a spherical plain bearing. The inner ring is made from either hardened bearing steel or hardened chromium steel, depending on the sliding contact surface required.

2) Outer Ring The outer ring of a spherical plain bearing has a cylindrical or parallel

outside diameter and a spherical inside diameter into which the ball type inner ring fits. It is made from hardened steel which can be coated with bronze or PTFE depending on the sliding contact required.

It should be noted that due to the 'Ball and Socket' type arrangement of the inner and outer rings, these bearings can accept a certain amount of misalignment or tilting of the shaft relative to the housing, in much the same way as a spherical roller bearing.


Due to the large area of contact between the inner and outer rings, the bearing can accept very high radial loads and a certain amount of axial load at slow rotational or oscillating speeds.

DIAGRAM 1

In addition to the standard types, as shown in diagram 1, they also manufacture several types with special features:

DIAGRAM 2

Angular Contact - designed to take angular loads, it looks like a normal ball bushing sliced through the centre


Thrust Type - Designed to take thrust loads only.

DIAGRAM 3

Extended inner ring - the inner ring is extended to eliminate the use of spacers.

DIAGRAM 4

Sealing - many of the bearings can be supplied with a built in sealing arrangement.

Numbering System We carry INA Elges Brand plain bearings and consequently use their numbering system. The Numbers consist of a prefix, size designation and suffix.

Part No Explanation GE__DO Steel on steel types - standard type, available sealed with the additional

suffix 2RS GE__LO Steel on steel - extended inner ring GE__ZO Steel on steel - standard type - inch sizes GE__SX Steel on steel - angular contact typ GE__AX Steel on steel - thrust type GE__UK PTFE (Teflon) on hard chrome type - available sealed - suffix 2RS GE__SW PTFE on hard chrome - angular contact type GE__AW PTFE on hard chrome, thrust type GE__HO Similar to DO type but with extended inner ring


Numbers The numeric section of the part number for metric dimensioned bearings is the ID size in millimetres. For example GE 12 DO would fit a 12mm shaft. In inch dimensioned bearings (ZO) the number is derived from the nearest mm size after converting inches to millimetres. The table below gives examples. Shaft Size (inch) Shaft Size (mm) Part No 1/2 inch 12.7mm GE 12 ZO 7/8 inch 22.225mm GE 22 ZO 1 inch 25.4mm GE 25 ZO 1-1/2 inch 38.1mm GE 38 ZO

Rod Ends

Rod Ends are small size self aligning spherical plain bearings which can take radial loads and two directional thrust loads at the same time.

Rod Ends cater for applications such as control linkages in machine tool,, textile industry, farm equipment, packaging machinery, industrial robots and many other applications.

Male Rod Ends Female Rod Ends

The body is made from low carbon steel, cadmium or zinc plated to resist corrosion, and the ball is made of sintered steel which is oil impregnated during manufacture. They have good static load capacity but as a general guide the actual load should be limited to 1/3 to 1/2 of the load capacity listed in the rod end brochure to provide for long life of the rod end. An optional extra is the provision of a grease nipple for lubrication and BR2 Plus is the right type of grease to use in these parts. However, if grease lubrication is not used, they can be oil lubricated by hand. Rod ends are available with either a right hand or left hand thread on the shank. This is so that the rod end will resist unscrewing it's self in certain applications. Male and female threads are available and the female unit has either a wrench flat or formed nut to aid assembly.


Whilst the open style rod end is the norm, an alternative is the stud type shown to the right. The stud type is normally supplied on a female type rod end and may be listed as L type or L-Balls. The open type is sometimes referred to as INSERT type. In left hand thread types, the stud thread remains a standard right hand thread.

Part Numbers - Imperial We use the FK numbering system for imperial rod ends (see appendix A). This consists of a prefix, the hole size in 16ths of an inch, and a suffix if applicable. Economy Series (CM, CF) The economy series rod ends have a case hardened steel ball which has been hard chrome plated. The body is low carbon steel, zinc plated, chromate treated. Numbering System: CM Male Type Right Hand Thread CF Female Type Right Hand Thread CML Male Type Left Hand Thread CFL Female Type Left Hand Thread The above prefixes are followed by the size in 16ths of an inch. For Stud type add the suffix Y, eg. CM6Y. For grease nipple add the suffix Z (not all sizes can be supplied with this option), eg. CF8Z. A PTFE liner can also be supplied - add the prefix T, eg. CM12T. Commercial Series (M/F) The precision series rod ends have a low carbon steel ball which has been hand chrome plated. The race is sintered Phosphor bronze, oil impregnated, and the body is low carbon steel, zinc plated and chromate plated. Prefixes:

M Male - right hand thread ML Male - left hand thread F Female - right hand thread FL Female - left hand thread

Suffixes:

Y Stud type Z Grease nipple

Example: M4SBZ - male right hand threaded with grease nipple, 1/4 inch hole.


Part Numbers - Metric We use the THK numbering system for Metric rod ends (see Appendix B). This is similar to the Aurora system in having a suffix indicating type followed by the hole size in millimetres, and a suffix to indicate variations to the standard. Prefixes:

PHS Female Type POS Male type LHS Studded type (female only)

Suffixes:

Blank Right hand thread L Left hand thread

Example: PHS 8 L - Female left hand thread with 8mm hole. Link Balls (RBL, RBI, TBS, ABI)

RBL

RBI

TBS

ABS These are low priced rod-ends, manufactured by attaching a stud by friction welding, to a bearing steel ball and using this for movement in a diecast holder. The spherical slide part is finished to a mirror finish and they have excellent wear resistance. They have a large oscillation angle.


Numbering System The RBL + Size in mm. If a boot is added (as shown in the diagram above, add D. For left hand thread, add L). Example: RBL10DL - 10mm with boot and left hand thread. When supplied, the boot is Neoprene rubber. When the boot is added the inclination angle is reduced by 5%-10%. General Comments We rely on our customers to select the type and size of rod end for their particular job. The factors which they will have to consider include Dynamic and Static load, Rotational speed and operational conditions. Rod ends normally take radial loads but can take thrust loads and the proportion of thrust to radial load needs to be taken into account in the selection process. There is a limit to the operating speed which IKO sets at 30 m/min. There is also a limitation on the permissible angle of tilt and this is shown in the manufacturers catalogues. The threaded shanks of rod ends are comparatively long and this feature permits an adjustment to be made to the operating position of the rod end. However, the section of thread in contact with the mating rod should be at least 1.25 times the diameter of the thread. Ball Joint Assemblies Ball joint assemblies are used as part of a linkable system in industrial applications. The SPG type is a high strength design with good wear resistance suitable for heavy duty service. SPG type is fitted with a weather resistant dirt shield. Type SP is similar but without the dirt shield. These products are made from low carbon steel with the ball stud surface hardened for wear resistance. The ball cavity is packed with high wear lubricant. Part Numbers SPG - Shielded Type SP - Unshielded Type The numeric part of the number is not related to the size but is nearly a part number. For left hand thread add the suffix LH. Example: SPG100441 - Shielded type, 3/8.24 / left hand thread.


A9021 - Questionnaire Name: Branch (eg QAA)

Employee No (from Payslip): Date:


Questions Answers

Q1. List 3 types of shifting surfaces which may be found on plain bearings.

A. Hard steel inner ring on steel outer ring

B. Stainless steel inner ring on bronze outer

C. Hard steel ring on Bronze outer ring

D. Chromium steel inner ring on PTFE Outer.

E. Bronze inner ring on chromium steel outer

Q2. Which of the listed components are found in a plain bearing?

A. Inner Ring

B. Rolling Elements

C. Cage

D. Outer ring

Q3. Standard bushings are of a radial design. List 3 other types.

A. B. C.

Q4.

Diagnose the part number GE25UK 2RS by typing the numbers and letters into the box provided. For example, it you think that 25% is the pore size then type 25 in box A.

A. Bore size

B. Spherical Plain Bearing

C. Sealed both sides

D. PTFE on Hard Chrome

Q5. Which of the applications listed are possible uses of Rod Ends?

A. Control of linkages in machine tools

B. Control of linkages in Textile Industry

C. Farm Equipment

D. Industrial Robots

E. Packaging Machinery

Q6. Rod ends which have a bolt protruding instead of a hole are called…

A. Bolt Type

B. Stud Type

C. Standard type


A9021 – Questionnaire (cont.) Name: Branch (eg QAA)

Employee No (from Payslip): Date:


Q7. What does the suffix Y stand for in the part number CM6Y?

A. Stud Type

B. Grease Nipple

C. Male - left hand thread

Q8 Give the details requested for a RBL 10 DL Bearing.

A. RBL Hole type Stud Type

B. 10 10 mm 1 inch

C. D With Boot With Nut

D. L Extended Length

Left hand thread

Q9. Where would you look to find the permissible angle of tilt for a Rod End?

A. Stamped on product

B. Product packaging

C. Manufacturers Catalogue

Q10. How does a SP type ball joint differ from a SPG type?

A. SPG is Unshielded type.

B. SP is shielded type.

C. SP is unshielded type.

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