gerald boggs' wood chisel · 2017-04-25 · gerald boggs' wood chisel wood chisel by:...

Gerald BoGGs' Wood ChiselWood ChiselBy: Gerald Boggs, Virginia

Acoupleofyearsago,IjourneyedovertotheWestCoasttospendsometimeworkingonwoodenboats.Iwasre-quiredtobringanumberofhandtoolswithme,thischiselwasoneofthem.Fig.1

Typically,thehandleofawoodchiselcanbeattachedtothebodybyatangorbyasocket.Iamshowingthetangmethodinthisarticle.

ThebodyofthechiselismadefrommildsteelwithapieceofO-1laminatedonfortheedgematerial.Fig.2

IprefertohavemyO-1mate-rialcutandreadytogobeforeIstartmakingthechisel.Thissavestimewhenitcomestimetodrawdownthebladeandweldonthetoolsteelpiece.

MybarofO-1is1-inchwideby¼-inchthick,andIuseabouta1-inchlengthofittolaminateontothebladeofthechiseltomaketheedgematerial.

HotcuttingtheO-1fromthebargivesmeachamferontheendofthebarwhichisincorporatedintothescarf

forforgeweldingontothemildsteelblade.Fig.3

OnceIhavecuttheO-1tolengthandhotraspedorgroundtheendtoananglethatIthinkwillhelpwiththeforgeweld(scarf )IliketokeepitwarmbythesideofthefireasIpreparetheotherpieceofthechisel.

Usea4½-inchlengthof¾-inchdiameterhotrolledsteelforthebasematerial.

Thefirstjobistoisolatethematerialtoformthetangforthehandle.Icomebackfromtheendofthebartothe½-inchmark,centerthefullerandneckthebartoabout5⁄16-inch(+).

IdislikesharpbutcheringdiesorhandtoolswhenImakeatenon,preferringtouserounddies.Idressthequarterroundrootofthedrawntenonlater,ratherthanriskcracksformingfromasharptransitionmadenow.

I'mshowingtheuseofaguillotinetoneckinforthetang,butavarietyofmethodsexistdependingonyourskillorinterestlevel.Fig.4

A 1-inch wide wood chisel made from mild steel with an O-1 tool steel edge

The O-1 block placed onto the mild steel body in prepa-ration for welding

A guillotine is being used to isolate the material for the tang of the chisel. Marks are ½˝ and 1½˝ from the end

Hot cutting the O-1 material from the bar starts to create the welding scarf

Thefinishedtenonshouldbeapproximately5⁄16squarewhenfinished.

Ineverfullertothefulldepthrequired,preferringtoreachmymeasurementobjectiveasIfinishthetang.Ful-leringtoodeepnowcanleadtocracksattherootoranundersizedtangwhenfinished.

Oncethematerialforthetanghasbeenisolated,Ineckinabout1-inchbeneaththeshoulderofthetangandreducethestocksizethere.Fig.5

Idon'tusuallymeasuretheresult,butItrytogetaround½-inchdiametermaterialwhenfinished.Iftheareastartstolookvisuallyweak,Istopforgingthere.

Unfortunately,frommyreadingatleast,thispartofthechiselcansometimesbecalledtheneck...whichmaycausealittleconfusion.Itisalsosometimesreferredtoastheshank.

Oncetheneckistomyliking,Idrawdownthetangtoasquarecrosssectionwithparallelsides,ashortpieceofsquarebarineffect.Figs.6&7

Delayingthefinalforgingofthetangmaterialandkeep-ingitasshortaspossibleforaslongaspossiblehelpstopreventcrackingatthetransitionbetweenthetangandtheshoulder.Crackingcanbecausedbytheinertiaofthetenonmaterialasyouforgeotherbitsalongthebar.

Abolsterplateorheadingblockisrequiredtosetanddresstheshoulderofthetang.Ihaveapieceof⅜-inchby2-inchbarwitha⅜-inchsquareholepunchedanddriftedononeface.Theedgesofthesquareholehavebeenrelieved,againtohelppreventcrackingatthebaseofthetang.Fig.8

Thebeautyofusingmildsteelasthebodyisthatyoucanisolatetheheattotheshoulderareawithquenching.Withthebolsterpositionedoverthehardyhole,drivetheshoul-derintotheplate.Figs.9&10

Thebolsterisnotmeanttoshapethetangmaterial.Usingthebolstertoshapethetangcancausetangmaterialtobeforcedbackintotheshoulderformingacoldshut.

Ifthetangisgettingcaughtinthebolster,refinethetangonthefaceoftheanvilwithyourhandorsethammerandtrythefitagain.Finishwithafileandthebolsteragain.

Gerald BoGGs'

Neck in at the 1½˝ mark using your rounding hammer over a suitable portion of the bick

Draw the tang material out to a uniform square cross section over a round edge of the anvil

Here is the result thus far

A bolster used to set the shoulder of the tang

Wood ChiselEithernow,orwhenyouhavedrawndownthebladema-

terial,dressthetaperfromtheshoulderofthetangdowntotheneck.Workwithyourhandhammerattheedgeoftheanvilandfinishwithyourhotrasptogetasmoothresult,somethingthatyoudon'tmindhandling.Fig.11

Nowitistimetoturnyourattentiontothebladeofthechisel.Mychiselis1-inchwide,¼-inchthickandmeasures6-incheswhenmeasuredfromcuttingedgetothemiddleoftheneck.Fig.12

Idrawthebladedownto1-inchwide,leavingitalittlethickofmydesired¼-inchdimension.LeavingthebladethicknowwillhelppreventthebladefromgettingtoothinwhentryingtoblendinthescarfoftheO-1toolsteelbit.

Bringthetoolsteelbitandthemildsteelbladetoanorangeheat.PlacetheO-1ontopofthemildsteelandfluxbothpieces.ReturntothefirewiththeO-1uppermost.Fig.13

Forgeweldingtoolsteeltoanythingrequiresalowerweldingheatthanistypicallyused.GettingtheO-1toohotcandestroyitsalloyproperties.

YoucannotturnthebladeinthefireortheO-1willfallofftheblade.

HavingthemildsteelbladelowerinthefireresultsinitgettingwarmerthantheO-1,agoodthinginthiscase.

WeldwhentheO-1reachesaniceorangecolor.JustaimtotacktheO-1tothemildsteelsothatyoucannowturnthepieceinthefireasyoutakeanother(low)weldingheat.

TheroundedgeoftheanvilfacecanbeusedtohelpblendinthescarfoftheO-1tothemildsteel.Holdthemildsteeluppermostandovertheoffsideedgeoftheanvil.PullthebladebackontotheanviluntiltheO-1iscaughtbytheroundedgeandthemildsteelraisedslightly.

UsehalffacedblowsfromyourhandhammertohelpsecuretheweldandblendinthetoeoftheO-1'sscarfintothemildsteel.

Theotherendofthechiselisnotsoimportantasanyuglinesscanbetrimmedawaywithyourhotcut,beginningthebevelofthecuttingedge.

The shoulder of the tang is driven into the bolster plate over the hardy hole. Work until all gaps are closed

Refine the material from the neck to the shoulder of the tang either now or after drawing down the blade

Draw the blade down to 1˝ wide by ¼˝ thick

The shoulder of the tang and the heading block that trued it up

The O-1 is placed on top of the mild steel and kept up-permost in the fire to prevent overheating

Draw the tang material down to a pyramid shaped taper of the required length

Drawdownthebladeuntilitis1-inchwideand¼-inchthick.Hammerfinishthebevelsontheedgeofthebladeasyouworkdownthematerial.Figs.14&15

"Aminuteattheforgenowwillsave10atthebenchlaterwithafile."Ofcoursethegrinderdidsomewhatlevelthatplayingfield,butitisstillagoodmaxim.

Excessmaterialisremovedwithahotcut.PositiontheO-1onthebottomofthelamination,placingthebevelfromthehotcutintherightorientation.

Oncethebladehasbeenroughedout,turnyouratten-tionbacktothetangmaterialanddrawthesquaretangouttoapyramidshapedtaper.Fig.16

Ensurethatthechiselisasstraightasyouneedittobe.Somechiselshaveabendatthenecktoofferclearanceforyourhandduringuse.

Grindorfilethecuttingedgeclosetoyourdesiredout-comeandthenheattreattheblade.Heattreatpriortoput-tingonthefinalperformanceedgetopreventacontamina-

The result of welding the O-1 onto the mild steel blade. The O-1 will be on the bottom of the finished chisel

The bevels on the edge were first placed with the ham-mer and then filed to suit

The lower ferrule prevents the handle material from splitting as you work

The upper ferrule prevents the struck end of the tool from splitting or being crushed

Gerald BoGGs'

tionoftheedgematerial."Ifablacksmithwillakeenedgewin,theymustforgethickandthenfilethin."

Theferrulesofthehandlearemadefrompipeorconduit.Theferruleattheshoulderofthetangis⅝-inchIDandtheferruleatthestruckendis¾-inchID.Figs17&18

Thetwodifferentmetalsareclearlyvisibleattheedgeoftheblade.TheO-1isplacedonthebottomoftheedgewiththemildsteeluppermost.Fig.19

The two different metals clearly visible at the edge of the chisel, with the O-1 on the bottom, at the cutting edge

The finished chisel ready for my tool box

Gerald Boggs owns and operates his own business as a black-smith (single occupation) and will be teaching at the 2016 ABANA conference in Salt Lake city next July.

Wood Chisel