granite surface plates and accessoriesjwdonchin.com/starrett/catalog/pdf/481.pdf · 483 certified...

GRANITE SURFACE PLATESAND ACCESSORIES

J.W. DONCHIN CO. 4841-43 W. Chicago Ave. • Chicago, IL 60651-3224Ph: 773-261-2182 • Fax: 773-261-2867 • [email protected] • www.jwdonchin,com

GRANITE SURFACE PLATES AND ACCESSORIES

140 TEST INDICATORS AND HOLDERS Introduction

481 GRANITE SURFACE PLATES AND ACCESSORIES

482 Granite Surface Plates and Accessories

483 Technical Information

484 Custom Engineered Granite Solutions

485 Technical Capabilities, Examples of Custom Applications Capabilities, Assembly Integration

486 Crystal Pink Granite Surface Plates

487 Crystal Pink Granite Surface Plates (continued)

488 Crystal Pink Granite Surface Plates (continued)

489 Charcoal Black Granite Surface Plates

490 Surface Plate Stands, Surface Plate Cleaner

491 Cabinet Type Surface Plate Stands, Surface Plate Covers

492 Granite Metrology Accessory Products, Three-Face Granite Tri-Squares

493 Five-Face Master Squares, Granite Parallels

494 Accuracy Assurance Products & Services, Calibration Services

482

Granite Surface Plates andAccessories

In 2006, The L.S. Starrett Company acquired Tru-Stone Technologiesin Waite Park, MN. With this acquisition, a broad variety of newcapabilities are now available to Starrett customers.

OEM CapabilitiesOur Tru-Stone Technologies Division continues to provide solutionsto customers in precision granite, carbon fiber, ceramic, highprecision vacuum chucks and other materials. We offer granitemachine bases and surface plates to meet your requirements up to55 feet long and weighing 72 tions

Whether your application requires a simple standard surface plateor a large OEM assembly, the Tru-Stone Technologies Division willwork with you to fulfill those requirements.

Every linear measurement depends on an accurate referencesurface from which final dimensions are taken. Starrett PrecisionGranite Surface Plates provide this reference plane for workinspection and for work layout. Their high degree of flatness, overallquality and workmanship also make them ideal bases for mountingsophisticated mechanical, electronic and optical gaging systems.

MaterialThe granite for Starrett surface plates has been selected for thebest balance of physical properties, maximum resistance to wearand for deflection under load. Each plate has been lapped to a finemicroinch finish to minimize tool wear and drag.

The most important element in the performance and life of granitesurface plates is the percentage of quartz that is present in thestone. Quartz is more than twice as resistant to wear as the otherminerals in granite. It provides bearing points that are of a hard,highly polished, smooth character which protect the accuracy andfinish of both the surface plate and the tools and instruments usedon it.

Starrett Crystal Pink Granite has the highest percentage of quartz ofany granite. Our Charcoal Black Granite also contains quartz, thougha slightly lower content than our Crystal Pink, but higher than otherplates produced with black granite. Higher quartz content meansgreater wear resistance. The longer a surface plate holds itsaccuracy, the less often it will require resurfacing, ultimatelyproviding better value.

Selection Accuracy Under LoadStarrett Crystal Pink and Charcoal Black Granite plates have athickness capable of supporting a total normal load equal to 50 lb.for each square foot (24kg for each 1,000 sq. cm) of surface arealoaded in the center of the plate – without deflecting the plate alonga diagonal of more than one-half the flatness tolerance. This is theaccepted rating in the U.S. Federal Specification GGG-P-463c.

In the situations where abnormal loading conditions are anticipated,Starrett can engineer and modify surface plate thickness to meetvirtually any requirement.

Ledges and ClampingSurface plates without work clamping ledges are recommended forsustained accuracy and reliability. Ledges are for work clampingpurposes only. If excessive torque is used when applying clamps toledges, it can adversely affect measurements taken near the plateedges. If clamping is important, T-slots and threaded metal insertsmay be installed in the surface.

AccuracySpecificationsStarrett Granite Surface Plates meet or exceed U.S. FederalSpecification GGG-P-463c.

Starrett Tru-Stone Technologies Division1101 Prosper DriveP.O. Box 430Waite Park, MN 56387

Starrett Granite Surface Plate Calibration• Calibration of granite surface plates, granite parallels (2 and

4-sided), granite straight edges , granite tri-squares, granite angle plates and granite squares

• Surface plate re-lapping• Calibration Lab is accredited by A2LA to ISO/IEC 17025*


*The L.S. Starrett Company’s accreditations are site-specific andtool-specific. The scope of accreditation is available upon requestto each location.

483

Certified AccuracyBefore shipment, each surface plate must pass a critical finalinspection to prove that its entire surface is within the specifiedtolerance. The final inspection is done with an autocollimator in a controlled atmosphere. This instrument is checked and certifiedagainst standards traceable to the U.S. National Institute ofStandards and Technology (NIST). The instrument’s certification is on file at the Starrett Tru-Stone Technologies Division in WaitePark, MN.

All shipments of Starrett precision granite products include aCertificate of Inspection which verifies traceability to NIST as wellas certifying that the inspection requirements of U.S. MIL-I-45208Aand Federal Spec. GGG-P-463c have been met.

Periodic InspectionEvery surface plate in use should be frequently inspected,especially under shop conditions where abrasion is common. Aneffective inspection program should include regular checks with anautocollimator. If tolerance variations are excessive, the plate canbe transferred to work involving less accuracy or it can beresurfaced to restore its original level of accuracy.

Resurfacing ServicesResurfacing facilities for Starrett and other makes of granitesurface plates are available in our plant or yours. For details, referto the last page of this section.

Design AssistanceStarrett Tru-Stone Technologies Division engineers will provideprompt assistance on any problem related to surface plate design,installation or use. Our staff is available to assist in your design oflarger OEM projects.

To get the best service and value from any granite plate, contactStarrett Tru-Stone.

Technical Information

AccuracyStarrett Granite Surface Plates are manufactured in three grades of accuracy:

◆ Grade AA - Laboratory GradeThis is typically specified for precision operations in constanttemperature gaging rooms and metrology departments.

◆ Grade A – Inspection GradeThis is typically specified for general work in quality control.

◆ Grade B – Toolroom GradeThis is typically specified for production checking workthroughout the shop.

Unilateral Flatness ToleranceOverall flatness tolerance is based on unilateral measurement.All points on the work surface shall be contained between twoparallel planes separated at a distance no greater than the amount specified for each particular grade and size as shown in our listings.

Repeat Reading ToleranceRepeat reading tolerance is easily checked with Repeat ReadingGage. This gage detects local areas, not overall flatness

In addition to the overall flatness tolerance referred to above,Starrett provides repeat reading tolerances as follows:

Full Indicator Movement (F.I.M.)

Diagonal In Microinches and (Microns)

Inches (mm) Grade AA Grade A Grade B Obtained

Through 30� (750) 35 (.9) 60 (1.5) 110 (2.8)

Over 30-60�(750-1500)

45 (1.1) 70 (1.8) 120 (3)

Over 60-90�(1500-2250)

60 (1.5) 80 (2) 160 (4)

Over 90-120�(2250-3000)

75 (1.9) 100 (2.5) 200 (5)

Over 120-150�(3000-3800)

90 (2.3) 120 (3) 240 (6)

Over 150� (3800) 100 (2.5) 140 (3.6) 280 (7)

All Sizes 25 (.6) 50 (1.3) 100 (2.5)When Specified

A repeat reading gage detects minute variations of the surfacewithin the unilateral flatness tolerance of the whole surface.

Inspecting a granite plate with an autocollimator.

When NotSpecified


484


For Oversize Parts and AssemblingStarrett has unparalleled experience and expertise in building special,extra-large granite surface plates and custom products from graniteto meet specific requirements.

All Starrett special surface plates are made from single, solid slabs ofgranite quarried in one piece, machined in one piece and finished toyour specified dimensions and tolerances.

Above: Starrett offers unparalleled design expertise and experience towork with your engineers to create the ideal custom solution for yourapplication.

Special plates are usually requested in two different categories:

Inspecting oversize parts: The first category is for inspectingoversize parts and assemblies such as diesel engine blocks andcrankshafts, vehicle frames, missile components and ground supportequipment.

Inquiries for granite surface plates to accommodateoversize parts and assemblies should indicate:

1. Type of part to be staged

2. Distribution of weight

3. Degree of inspection accuracy required

4. Work holding requirements

5. Footing requirements, ceiling height andavailability of heavy-duty work-handling equipment

Modifying standard plates: The second general categoryrelates to modifying standard plates or building special surfaceplates for work-holding attachments of many different types.

Threaded and solid inserts, adaptor holes, T-slots, dovetails – almostanything added to conventional gaging fixtures can also be addedto Starrett surface plates, extending their accuracy andversatility for numerous applications. Precision edges, made squarewith the top surface and adjacent edges, as well as precisiongraduated rules can also be added.

We can build and assemblethis work-holding or specialgaging equipment to veryclose tolerance in eitherfractional, decimal inch ormetric dimensions. Allspecial plates are quotedon an individual basis,

Custom Engineered Granite Solutions

Left: We can build custom fixtureplates that provide exceptionalpositional accuracy for one orseveral of your applications.

Tru-Vac Vacuum & Air-lift Technology Starrett provides both standard and custom solutions forvacuum chucking, positioning or air-lift part transfer. Ourinnovative Tru-Vac technology integrates the stability andprecision flatness of granite with a porous medium, usuallyceramic.

Tru-Vac can eliminate the need for mechanical clamping withits inherent part distortion or damage risk by utilizing vacuumdraw at specific locations or distributed over the entire surfaceof your part.

Conversely, Tru-Vac technology can be utilized to providepositive pressure to allow your delicate parts to glide on acushion of air from which they can be safely lifted or transferredto the next operation.

Starrett engineerswill work with youto select thebest porousmedium for your applicationbased on surfacearea, flatness, wear,and desired airflowcharacteristics.

Tru-Vac technology can beutilized in air chucks smaller than ahockey puck or larger than a conference room table. Vacuumzones can be of nearly any shape by virtue of our CNC millingcapabilities.

Multiple zones can be utilized to accommodate a variety of partsizes or even to provide a combination of negative and positivepressure for controlled part movement.

Above: Tru-Vacvacuum chuck.

based on complexity and tolerance requirements. We will workwith you to give you the best, most economical solution for yourapplication.

The uses of Starrett special granite surface plates are limitedonly by the imagination of the creative tool designer. Inquiries forspecial surface plates like the type shown will be studied andrecommendations given without obligation.

485


Technical CapabilitiesStarrett has a variety of technicalcapabilities that, combined with ourexpertise, makes us theperfect choice for your customgranite requirements.

These capabilities include:

• Drilled and bored holes withprecise size and location (right)

• Inserts turned and inspectedin-house for quality control andcustom options

• T-slots and inserts bondedusing proprietary methods

• CNC milling of patternsof clearance areas

• Specialty slot milling capabilities

• Unsurpassed dimensionalcontrol of flat, square, andparallel surfaces

Examples of Custom Applications CapabilitiesTop/Left: Multi-plane baseswith precise insert accuracy.

Right: Laser verifiedgeometric accuracy.

Bottom/Left: Extremely large(or small) part capabilities.

Assembly IntegrationIn addition to collaborating on thedesign and building of yourmachine foundation, Starretttechnicians are skilled at value-added assembly.

Using precision equipment in ourassembly laboratories, we canprovide you with the next levelassembly, such as adding bearingrails, encoder rails, screw drives,stages, or vibration dampingdevices.

Having this assembly done at our factory provides accountability foraccurate performance.

486


Starrett Crystal Pink Granite Surface Platesare accurate for use in metrologylaboratories and wear resistant for use inabrasive shop environments.

Crystal Pink is the finest, most durable granite surface plate available to industrytoday. The name is derived from the factthat it has the highest crystalline quartzcontent of any granite surface plate.

Crystal Pink Granite Surface Plates

No Ledge Grade AA LaboratoryFlatness

Surface Size Thickness Unilateral Tolerance Weight

Inch mm Inch mm Inch mm Lb. kg EDP12� x 12� 300 x 300 55 25 80601

12� x 18� 300 x 450 4� 100 .000050� 0.0012 85 39 80610

18� x 18� 450 x 450 125 57 80619

18� x 24� 450 x 600 .000075� 0.0019

248 113 80628

24� x 24� 600 x 600 6� 150

330 150 80646

24� x 36� 600 x 900 .000100� 0.0025 495 225 80655

36� x 36� 900 x 900 .000150� 0.0038 745 338 80701

36� x 48� 900 x 1200 8� 200 .000200� 0.0050 1320 599 80710

36� x 60� 900 x 1500 10� 250 .000250� 0.0063 2065 937 80719

36� x 72� 900 x 1800 12� 300

.000300� 0.0076 2970 1347 80728

48� x 72� 1200 x 1800 .000350� 0.0088 3960 1796 80755

48� x 96� 1200 x 2400 16� 400 .000500� 0.0127 7040 3193 80773

No Ledge and Two Ledge are listed thispage and the following two pages. FourLedge available by request.

Continued on the following two pages.

NOTE: Other sizes available by request.

Surface FinishEven distribution of large quartz crystalsprovides a smooth finish, whichsignificantly reduces wear on the surfaceplate and the instruments used on it. Thisfine micro-finish, combined with the naturalvoids in thesurface, prevents wringing and provides avelvety-smooth tool action.

Wear LifeOur experience with surface plateperformance in customers’ plants showsthat non-quartz-bearing granite in averagedaily use requires resurfacing about once ayear. Crystal Pink plates used in thesesame plants have required resurfacing onlyonce every three to five years, on average.

487

Crystal Pink Granite Surface Plates (continued)


Starrett Crystal Pink:◆ Meets or exceeds U.S. Federal

Specification GGG-P-463c for flatness◆ Great surface hardness and wear

resistance – the highest percentage ofquartz crystals of any granite plate

◆ Smooth, jewel-like quartz bearing points protect accuracy and finish ofboth the surface and the tools used on it

◆ Quality and economy combined◆ Comparable to black granite plates while

outwearing them as much as 5 to 1◆ Meets or exceeds 50 lb. per square foot

(24kg per 1,000 sq. cm) load bearingspecifications. Available in 100 lb.(45kg) test series

Standard-size plates are mounted onresilient support pads, providing isolationfrom normal vibration and a non-distorting3-point suspension.

Packed one per crate with skids for forklifthandling.

No Ledge Grade A InspectionFlatness



12� x 18� 300 x 450 4� 100 .000100� 0.0025 85 39 80613

18� x 18� 450 x 450 125 57 80622

18� x 24� 450 x 600 .000150� 0.0038

248 113 80631

24� x 24� 600 x 600 6� 150

330 150 80649

24� x 36� 600 x 900 .000200� 0.0050 495 225 80658

36� x 36� 900 x 900 .000300� 0.0076 745 338 80704

36� x 48� 900 x 1200 8� 200 .000400� 0.0101 1320 599 80713

36� x 60� 900 x 1500 .000500� 0.0127 2065 937 80722

36� x 72� 900 x 1800 10� 250 .000600� 0.0152 2475 1123 80731

48� x 72� 1200 x 1800 .000700� 0.0177 3300 1497 80758

48� x 96� 1200 x 2400 12� 300 .001000� 0.0254 5280 2395 80776

No Ledge Grade B Toolroom12� x 12� 300 x 300 55 25 80607

12� x 18� 300 x 450 .000200� 0.0050 83 38 80616

18� x 18� 450 x 450 4� 100 125 57 80625

18� x 24� 450 x 600 .000300� 0.0076

165 75 80634

24� x 24� 600 x 600 220 100 80652

24� x 36� 600 x 900 .000400� 0.0101 495 225 80661

36� x 36� 900 x 900 6� 150 .000600� 0.0152 745 338 80707

36� x 48� 900 x 1200 .000800� 0.0125 990 449 80716

36� x 60� 900 x 1500 .001000� 0.0254 1650 749 80725

36� x 72� 900 x 1800 8� 200 .001200� 0.0304 1980 898 80734

48� x 72� 1200 x 1800 .001400� 0.0355 2640 1198 80761

48� x 96� 1200 x 2400 10� 250 .002000� 0.0508 4400 1996 80779

Continued on the following page.


Special RequirementsShould your application require somethingother than a standard surface plate, we canprovide you with custom options.

Starrett can produce your plate from pink,black or gray granite.

Custom sizes and thicknesses are availableupon request to meet your needs.

We can also add holes, counterbores,threaded or solid stainless steel inserts,and t-slots to your surface plate.

Contact Starrett Tru-Stone for assistance.

How to OrderSpecify: 1. Surface size of plate

2. Grade AA, A or B tolerance 3. Number of ledges – two

or none.

488


Crystal Pink GraniteSurface Plates (continued)Two Ledge Surface Plates

Two Ledge Grade AA LaboratoryFlatness



12� x 18� 300 x 450 4� 100 .000050� 0.0012 78 35 80611

18� x 18� 450 x 450 120 54 80620

18� x 24� 450 x 600 .000075� 0.0019

224 102 80629

24� x 24� 600 x 600 6� 150

306 139 80647

24� x 36� 600 x 900 .000100� 0.0025 460 209 80656

36� x 36� 900 x 900 .000150� 0.0038 710 322 80702

36� x 48� 900 x 1200 8� 200 .000200� 0.0050 1250 567 80711

36� x 60� 900 x 1500 10� 250 .000250� 0.0063 1950 885 80720

36� x 72� 900 x 1800 12� 300

.000300� 0.0076 2810 1275 80729

48� x 72� 1200 x 1800 .000350� 0.0088 3795 1721 80756

48� x 96� 1200 x 2400 16� 400 .000500� 0.0127 6750 3062 80774

Two Ledge Grade A Inspection12� x 12� 300 x 300 50 23 80605

12� x 18� 300 x 450 4� 100 .000100� 0.0025 78 35 80614

18� x 18� 450 x 450 120 54 80623

18� x 24� 450 x 600 .000150� 0.0038

224 102 80632

24� x 24� 600 x 600 6� 150

306 139 80650

24� x 36� 600 x 900 .000200� 0.0050 460 209 80659

36� x 36� 900 x 900 .000300� 0.0076 710 322 80705

36� x 48� 900 x 1200 8� 200 .000400� 0.0101 1250 567 80714

36� x 60� 900 x 1500 .000500� 0.0127 1950 885 80723

36� x 72� 900 x 1800 10� 250 .000600� 0.0152 2340 1061 80732

48� x 72� 1200 x 1800 .000700� 0.0177 3165 1436 80759

48� x 96� 1200 x 2400 12� 300 .001000� 0.0254 5060 2295 80777

Grade B Toolroom12� x 12� 300 x 300 50 23 80608

12� x 18� 300 x 450 .000200� 0.0050 76 34 80617

18� x 18� 450 x 450 4� 100 118 54 80626

18� x 24� 450 x 600 .000300� 0.0076

155 70 80635

24� x 24� 600 x 600 210 95 80653

24� x 36� 600 x 900 .000400� 0.0101 460 209 80662

36� x 36� 900 x 900 6� 150 .000600� 0.0152 710 322 80708

36� x 48� 900 x 1200 .000800� 0.0203 955 433 80717

36� x 60� 900 x 1500 .001000� 0.0254 1560 708 80726

36� x 72� 900 x 1800 8� 200 .001200� 0.0304 1870 848 80735

48� x 72� 1200 x 1800 .001400� 0.0355 2530 1148 80762

48� x 96� 1200 x 2400 10� 250 .002000� 0.0508 4215 1912 80780

Continued from the previous two pages.


While not listed, both pink and blackgranite Four Ledge Starrett SurfacePlates are available by request.



or none.

489


No Ledge Grade AA LaboratoryFlatness


Inch mm Inch mm Inch mm Lb. kg EDP12� x 12� 300 x 300

.000050� 0.0012 55 25 80900

12� x 18� 300 x 450 4� 100

85 39 80906

18� x 24� 450 x 600 .000075� 0.0019

248 113 80912

24� x 24� 600 x 600 330 150 80918

24� x 36� 600 x 900 6� 150

.000100� 0.0025 495 225 80924

36� x 36� 900 x 900 .000150� 0.0038 745 338 80936

36� x 48� 900 x 1200 8� 200 .000200� 0.0050 1320 599 80942

36� x 60� 900 x 1500 10� 250 .000250� 0.0063 2065 937 80948

36� x 72� 900 x 1800 12� 300 .000300� 0.0076 2970 1347 80954

No Ledge Grade A Inspection12� x 12� 300 x 300

.000100� 0.0025 55 25 80902

12� x 18� 300 x 450 4� 100

85 39 80908

18� x 24� 450 x 600 .000150� 0.0038

248 113 80914

24� x 24� 600 x 600 330 150 80920

24� x 36� 600 x 900 .000200� 0.0050 495 225 80926

36� x 36� 900 x 900 6� 150 .000300� 0.0076 745 338 80938

36� x 48� 900 x 1200 .000400� 0.0101 1320 599 80944

36� x 60� 900 x 1500 8� 200 .000500� 0.0127 2065 937 80950

36� x 72� 900 x 1800 10� 250 .000600� 0.0152 2475 1123 80956

No Ledge Grade B Toolroom12� x 12� 300 x 300

.000200� 0.0050 55 25 80904

12� x 18� 300 x 450 3� 75 83 38 80910

18� x 24� 450 x 600 .000300� 0.0076

165 75 80916

24� x 24� 600 x 600 4� 100

220 100 80922

24� x 36� 600 x 900 .000400� 0.0101 495 225 80928

36� x 36� 900 x 900 .000600� 0.0152 745 338 80940

36� x 48� 900 x 1200 6� 150 .000800� 0.0203 990 449 80946

36� x 60� 900 x 1500 .001000� 0.0254 1650 749 80952

36� x 72� 900 x 1800 8� 200

.001200� 0.0304 1980 898 80958

48� x 72� 1200 x 1800 .001400� 0.0355 2640 1198 80966

Special RequirementsShould your application requiresomething other than a standard surfaceplate, we can provide you with customoptions.

Starrett can produce your plate frompink, black or gray granite. Custom sizesand thicknesses are available uponrequest to meet your needs.

We can also add holes, counterbores,threaded or solid stainless steel inserts,and t-slots to your surface plate.

Contact Starrett Tru-Stone forassistance.

Charcoal Black GraniteSurface Plates

Our charcoal black granite has a highquartz content which provides greaterresistance to wear and damage than otherblack granite plates.

This material has low water absorptionrates, thus minimizing the possibility ofyour precision gages rusting while settingon the plates.

This black granite creates little glareresulting in less eyestrain for individualsusing the plates.

We have chosen our charcoal black granitewith the specific intent of keeping thermalexpansion to a minimum.



or none.

Listed are No Ledge Plates – Two Ledge andFour Ledge Plates available by request.

NOTE: Sizes other than those listed are availableby request.

490


Surface Plate Stands

Our stands are constructed from welded square steel tubing toprovide exceptional strength and durability. Steel crossbeams arelocated at the proper support points to ensure maximum surfaceplate accuracy.

Stands are supplied with a scratch and abrasion resistant industrialpowder coated finish. In addition to our standard beige gray color,other colors are available upon request and at an additional charge.

Stationary stands come with leveling adjustors with the typicaladjustment being 2�. Rolling stands are fabricated with twostationary and two swivel casters.

Stands require no assembly. Order by surface plate size.

Surface Plate CleanerTo keep surface plates and other precisiongranite products in top condition, theyshould be cleaned frequently with StarrettCleaner. This helps prevent abrasion oftools by dirt and other foreign particles.

The liquid cleaner, which also acts as adegreaser and rust inhibitor, should be usedwithout water to minimize the risk ofrusting tools.

Supplied in a variety of containers as listed.

Tube Steel Stands

Stationary RollingSurface Plate Size Weight Stand Stand

Inch mm Lb. kg EDP EDP

12� x 18� 300 x 450 50 23 82220 82221

18� x 18� 450 x 450 65 29 82222 82223

18� x 24� 450 x 600 75 34 82224 82225

24� x 24� 600 x 600 85 39 82226 82227

24� x 36� 600 x 900 95 43 82228 82229

24� x 48� 600 x 1200 145 66 82230 82231

36� x 36� 900 x 900 165 75 82232 82233

36� x 48� 900 x 1200 185 84 82234 82235

36� x 60� 900 x 1500 205 93 82236 82237

36� x 72� 900 x 1800 235 107 82238 82239

48� x 60� 1200 x 1500 255 116 82240 82241

48� x 72� 1200 x 1800 265 120 82242 82243

48� x 96� 1200 x 2400 345 156 82244 82245

Description EDP

55 gal. (250 liter) Drum 81820

1 gal. (4.5 liter) Case of Four

81822

1 Quart (4.5 liter) Case of 2

81824

Waterless Cleaner81828(Case of Twelve

32 oz. bottles)

491


NOTE: Granite Surface Plate is notincluded with stand – order separately.

Cabinet stands provide a strong, rigid support for standard plateslisted, plus a handy place to store frequently used inspection toolsand accessories.

The standard height is 36� (900mm) from the floor to top of thesurface plate.

All stands made from heavy-gauge welded steel, have locking doorson the front. The 48� (1200mm) wide stands are equipped withdoors front and back unless otherwise specified. Stands are suppliedwith leveling screws or casters as listed. Order by surface plate sizeand thickness.

Cabinet Type Surface Plate Stands

Stand With Leveling WithSurface Plate Size Weight Screws CastersInch mm Lb. kg EDP EDP

24� x 36� 600 x 900 190 86 81504 81506

36� x 36� 900 x 900 245 111 81516 81518

36� x 48� 900 x 1200 300 136 81513 81515

36� x 60� 900 x 1500 365 166 81519 81521

36� x 72� 900 x 1800 440 200 81522 81524

48� x 72� 1200 x 1800 660 299 81525 81527

Vinyl CoversFor Surface Size

Inch mm EDP

12� x 12� 300 x 300 83020

12� x 18� 300 x 450 83021

18� x 18� 450 x 450 83022

18� x 24� 450 x 600 83023

24� x 24� 600 x 600 83024

24� x 36� 600 x 900 83025

24� x 48� 600 x 1200 83026

36� x 36� 900 x 900 83027

36� x 48� 900 x 1200 83028

36� x 60� 900 x 1500 83029

36� x 72� 900 x 1800 83030

48� x 60� 900 x 1500 83031

48� x 72� 1200 x 1800 83032

48� x 96� 1200 x 2400 83033

Surface Plate CoversWe highly recommend the use of surface plate covers to protect yourprecision granite investment. Prevent abrasive build up on yourplates with our covers made from heavy gauge vinyl with a softinterior lining. Our covers provide a tough, durable, protective outsidewith a soft cushion inside.

492


Three-Face Granite Tri-Squares provide an excellent, economicalway for accurately checking the X-Y-Z axes on CNC machine toolsand coordinate measuring machines.

Lying in the horizontal position, with an indicator in the spindle, the X and Y axes can be checked for 90º squareness. With the square in

the vertical position, tracing along the vertical edge of the squarecan check the perpendicularity of the Z axis.

Granite tri-squares may also be used in the same manner that steelsquares would be used for the direct checking of squareness andstraightness.

Toolmakers’ FlatsThese handy flats are small precisionsurface plates that are ideal for manyinspection and checking uses throughout theplant.

They are especially well suited for layout workand offer an easy, portable reference for gagingsmall parts.

Offered in Crystal Pink Granite or Impala BlackGranite, Starrett Toolmakers’ Flats are 12� longx 8� wide x 2� thick (300 x 200 x 50mm) andfinished to an overall tolerance of .0001�(0.0025mm).

The shipping weight is 20 lbs. (9kg).

Description EDP

Crystal Pink Granite 81803

Impala Black Granite 81802

Three-Face Granite Tri-Squares

Granite Metrology Accessory Products

Accuracy Grade – EDP No.

Dimensions AA Laboratory A InspectionInch mm Weight .000025�/6� TIR .000050�/6� TIR

Base Height Thickness Base Height Thickness Lb. kg (0.0006/150mm) (0.0012/150mm)

9� 12� 3� 225 300 75 23 10 81961 81962

12� 18� 4� 300 450 100 60 27 81964 81965

18� 24� 4� 450 600 100 120 54 81967 81968

NOTE: Other sizes quoted on application.

493


Five-Face MasterSquaresFive-Face Granite Master Squares arepopular for accurately checking the X-Y-Zaxes on CNC machin2.253e tools andcoordinate measuring machines.

Lying in the horizontal position with anindicator in the spindle, the X and Y axescan be checked for 90º squareness. Withthe square in the vertical position, tracingalong the vertical edge of the square cancheck the perpendicularity of the Z axis. Bytracing along the top edge of the squarewhile in the vertical position, it will checkparallelism of the table in the X and Y axesto the spindle.

Five-face master squares may also be usedon any work that requires the checking ofsquareness or parallelism.

Granite ParallelsProduced in two sizes, Starrett GraniteParallels are useful in setting up work onsurface plates and machine tables.Available in matched pairs, finished on twoopposite faces or all four faces. Storagecases are available at extra cost.

Starrett GraniteGrade AA Laboratory Grade A Inspection

Length x Thickness Unilateral Unilateral x Height Tolerance (TIR) 2-Face 4-Face Tolerance (TIR) 2-Face 4-Face Weight Per Pair Case Only

Inch mm Inch mm EDP EDP Inch mm EDP No. EDP No. Lb. kg EDP

12 x 1 x 2 300 x 25 x 50 .000025 0.0012 81695 81696 .000050 0.0025 81697 81698 4 2 81708

24 x 2 x 4 600 x 50 x 100 .000050 0.0038 81703 81704 .000100 0.0076 81705 81706 36 16 81710

Accuracy Grade – EDP No.

Dimensions AA Laboratory A InspectionInch mm Weight .000025�/6� TIR .000050�/6� TIR

Base Height Thickness Base Height Thickness Lb. kg (0.0006/150mm) (0.0012/150mm)

12� 12� 3� 300 300 75 41 19 81919 81920

14� 14� 3� 350 350 75 56 25 81922 81923

16� 16� 4� 400 400 100 98 44 81925 81926

24� 24� 4� 600 600 100 220 100 81931 81932

494

Tolerances for Repeat Reading of MeasurementFull Indicator Movement (F.I.M.) in Microinches and (Microns)

Diagonal Inches (mm) Grade AA Grade A Grade B Obtained

Through 30� (750) 35 (.9) 60 (1.5) 110 (2.8)

30-60� (750-1500) 45 (1.1) 70 (1.8) 120 (3)

60-90� (1500-2250) 60 (1.5) 80 (2) 160 (4) When 90-120� (2250-3000) 75 (1.9) 100 (2.5) 200 (5) not Specified

120-150� (3000-3800) 90 (2.3) 120 (3) 240 (6)

Over 150� (3800) 100 (2.5) 140 (3.6) 280 (7)

All Sizes 25 (.6) 50 (1.3) 100 (2.5) When Specified

A repeat reading gage detects minute variations of the surface within the unilateralflatness tolerance of the whole surface.


When resurfacing is done in your plant,tolerances for repeat reading ofmeasurement will be per the table fromU.S. Federal Specification GGG-P-463c,paragraph 3.3.3. Closer repeat readingtolerances of 25, 50 and 100 millionths can

Repeat Reading GageThis high-precision instrument provides afast check on surface plate repeatabilitywith readings taken on a high magnificationelectronic amplifier. This gage detects local error, not overall flatness.

The base has an adjustment knob for zero-setting the cartridge-type gaging head, andall contact points resting on the granite,including the contact point of the gagingcartridge, are carbide and lapped to a finefinish.

The instrument also accommodates AGD indicators with .375� (9.5mm)diameter stems. Extra-length contact pointsmay be required.

Description EDP No.

Repeat Reading Gage Only 81815

Case 81818

Accuracy Assurance Products & Services

Calibration ServicesStarrett calibration and resurfacing servicesare available for all types and brands ofgranite surface plates. When certification ofsurface tolerance is required, recalibrationservice with an auto-collimator will beprovided with accuracy traceable to theU.S. National Institute of Standards andTechnology.

Plates that need resurfacing can beserviced at Waite Park, MN, Jedburgh,Scotland, and Itu, Brazil. Calibration andresurfacing of tri-squares, master squares,master angles, V-blocks, parallels andstraight edges is also available at our atWaite Park, MN location

Resurfacing can also be done in your plant,saving crating and shipping costs as wellas equipment down time. The cost is basedon a square foot plate area with additionalcharge for travel. For a quotation, send us alist of plates, their sizes and the flatnesstolerance required.

only be assured if the resurfacing is done atour facilities.

RecalibrationRecalibrations are provided by our CalibrationLab which is A2LA accredited.

J.W. DONCHIN CO.Precision Measuring Equipment and Industrial Supplies since 1924.

www.jwdonchin.com

4841 W. Chicago Ave. - Chicago, IL 60651 • Phone: 773-261-2182 • Fax: 773-261-2867 • [email protected]

J.W. DONCHIN CO.

J.W. Donchin Co. was established in 1924 and has been known world wide ever since. Customer Service is our Main Focus. We offerExpert Product Knowledge, Large Stocking Inventory and Competitive Pricing to assist you in locating and selecting the correcttool or product to fit your needs. (J.W. Donchin Co. is one of L.S. Starrett’s largest stocking distributors.)

Contact Information:

Phone: 773-261-2182

Fax: 773-261-2867

Email: [email protected]

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