CAIN , I j WORKSHOP PRACTICE SERIES from Argus Books I .
Hardenin& Tempering ilnd Hear Treatment Tubal Cain 2. Vertical
Milling in the Home Workshop Arnold Tnrop 3. Screwcutting in the
L.lthe Martin Cleeve 4. Foundrywork for tile Amateur B.T. Aspin 5.
Milling Operations in the Lathe Tubal Cain 6. Me,lSuring and
MarkinB Metals Ivan law 7. The Art of Weldmg W.A. Vau!te 8. Sheet
Metal Work R.E. Wakeford 9. Soldering iJnd Brazing Tubal Cain 10.
Saw's and Sclwing lan Bradley 1 1 ffee/rop/alioS J. Poyner 12.
Drills. Taps and Dies Tubal Cam 13 Workshop Drawing Tubal Cain I'
Making Small Workshop Tools S. Bray 15 . Workholding in the Lathe
Tubal Cain 16. ElectriC Motors V.l. Cox 17 . C e a r ~ and Gear
Cutting I. Law 18. Basic Benchwork les Oldtidge 19. Spring Des/g"
imd ManufiJcture Tubal Cain 20. Metalwork and Machining Hints and
Tips lan Bradley 1. Hardening, Tempering and Heat Treatment In this
valuable book Tubal Cain takes the reader beyond the superficial or
the simply practical with explanations of the composition of steel,
its additives, and the effects of different temperatures on its
constituents. With a grasp of what changes are actually taking
place in the metal the care needed in following the practical
processes described becomes under-standable and will lead to better
and more consistent results. Flame, salt bath and furnace heating
are detailed, with information on accurate measurement or
recognition of temperature levels. For the average small workshop
operative or model engineer the discourses on tool material ,
hardening and tempering will be of most use, and in this connection
this book replaces the earlier "Hardening and Tempering Engineers'
Tools", providing a broader-based, more detailed and Lip to date
examination of the subject. ISBN 0- 242-837-5 . . .. 9 I HARDENING,
TEMPERING AND HEAT TREATMENT for model engineers Tubal Cain ARGUS
BOOKS ArV"" 10U that. chunk of iron 0)1 22 inch cube will conlain
IS much car\xln as I of cokell The importanl thing 10 apprsCiete al
Ihi. Stage is lhat lhe iron and carbon lorm a sO/ulio:>n. jusl
like the wge' in \'Ur lea. Aft.r passlr>glhrough a paSIV stage
whit", cooling the iron $Olidifiss at about 1130 C. end we r>OW
have a so/id $Olulion 01 iron IFs"itel and carbon. bm wilh $Ome of
'he carbon r>OW combining 10 form an I,on carbide. How...,., .
85 lhe melal cool. funhe. It. capacily 10 diuolve carbon
diminishes. and $Ome 'Ir.s carbon appear, .1 Ihs grllin boundaries
as graph;'e. The final sla,e does depend some ..... h.t on IIow 1
... 1 flg. l 5_ ot ___ ... , -. ..... "' ... "' _ " ___ ot_",-the
melal ha. e oc:usional "'hard spot"" al Ihe cor"". 01 a thin ich
remOVad moll of lhe carbon from tha Iron made In the bl ,-furnllich
a .. .. nkad a. "ceobon ,001 .Iee"' ... In geAlf.' " M,'d" 11 1
will conl.in lram 0.05% up 10 0.2" ca,bQn and "M.cIium" caobon "HI
Up 10 pe,hapt 0 6'IC.. ThHe lasl c.n be lougt>enMI by heat tt
lmenl. bu, not haode,*, ... trociee effect of the carbon. EY.n in
Ih' c'" of t .... "high f4Hed" ,001 . ' H'I - "1oVI 01 iron,
lungs,...,. cob.Ilt .nd ca,bon _ 11 is I.... pr'Mnca of c.obon
which provid.n m .... V of lhei, propen .... It is Hkltary ..
flection lha. OUr ..-joy""'" 01 rr....a engtn,,"ng d'p,nd, .ntire'
y on Ih' m""I" found in .he core 01 YOU' IUd pencil I --CHAPTER 2
Principles of the Hardening Process Hardening hlgh-clrbon steel is
easy _ people have beln doing it for ti'toullndl of Y"'" Just his,
the metal to che,..,. ,eej .nd qu.nch in cold wate, and 11>1own
in Fig 10 The9 case. Fig IS. 8uI I must emphasise Ihstlhe ... con
sideralions all apply only 10 !Ieel which has been bOlh healed and
cooled SLOWLY. so thal 11>8 li1l1e al""'l have ,ime la find
Ihei' .ighl places. and Ihe cheml""l changes al lhe Iowe.
ctillcalline have I;me 10 cornp4e!e. 11 is wpical of a o STRENGTH
!tun 0. 0 11." CARBON frIIoRDNESS " "hol ,oiled ba." Which hu (0'
$hould have' bften no.mallsed when vou it from the me.chanl Cold
d!1lwing (e.g . Brighl Drawn Mild Sleel"! ..... ill nol aller lhe
type of struClure IPearlile-Ferrite. or Pearhle-Cementlte) lhough
il mav altel Ihe me8 ductility. because lhe fo,ming p,ocess has
diSIOtIoW Ihe g.aln . The stfllCl u,es found wl>8n the .,eel is
cooied loo quickly for lhe changes la occu, .,e Quite differ renl.
So. let u. now have 8 lOok sI Ihe effect 01 Olher lhan slow
cooling. EFFECT OF COOLI NG RATE Lel u. 8gain consider Out pie9m.
In addition. Ihe ""Sl enit' is compelled 10 relein fa. mo.e ""rbon
Ihal It can normally hold at Ihe lower lemper.ture. TI>8
AuSlen"e crySt811 .'" put under eno.mous intemal Slress . od is
JUSt Ihe C(l(Idilion which is associated ..... i,h hardness. In
addition. Ihe Cementite which Is p.esenl is unable 10 QYslallise
normally. but InllBed Is con-strained inlO a needle_like struclure
(known 8$ an all, in chap",. deal wi,h Ihis In more detail.
npeclally in relalion 10 lhe special nnds of tumer's tOOls. which
musl be btough, up to a vel'! fine poliSh and sharp .... ALLOY
STEELS yea,s ago. wl>en .h, Slandan:J Practices" of model
en{l,,,"r-lng wer, beilljj established, ca'bon 11881 Wh just 1tI,.
_ en IlIoy of c,rbon end .... I. True. I1 woutd con.ain a few
Imourtties, for Ihe days of charcoal-Imelted iron were over (.hough
Hoit:apfi,1 was ill u";ng Humsman crucible loolsteel made from
imoorted D.nf m.nuleel .. re 01 high Clmon lIeel invot-.", ots
hlI1inO in Ih. "" .... ne. of arbon. rh, took long lim., but if _
arry .... 1 N .... proc:ass for sheI. lime .h&n ,h. c .. ban ..
ill pen,,,,,. onlv Iho" dl""'ce. for mod,l. we onlV need. Ih'" I.y
... - pertlap ... ,m,1I IS 0.005in. woule .., ..... - and Ihi' "
whal il ;odIieved t>. 'CASEHAROENING' The re v lou waYlIn wtlich
il an be done, """'" wtl" don't Involved Mlylh'ng ""'" IIIIn. bIov.
I,mp and som, SPecial compound. bul ... QU'" "",clic.1 lot !h.
model.ng,n ... Onc. !h, ..... rll>C. I.V" h been ca. bu';,ed the
p'" Cln be healed aM Qu.rn:hed and. In motl Cite cIoe. no! need InV
!.mPlfitlg. The .... It is I CO'. which it SlfOfIII and I .... gh .
nd , ..... rI., which is .Imosl 111.... -111.(1. F .. r1hI:al lent
beSI 10 .eplOduc. lhen on pagtt 33 As a lu"her guide. I IInd that
,he I.'ger boiling ring (one 01 'he ,pI'll 'vptt) on ou, Cred. 90R
.leculc cooka eached and ., 78O"C efte< runf'llng full on .'" 15
wllh no pan _ It : .nd Ih, li.ebed 01 Coo.1ie< Type 8R ' ... d
s,ove burning Phufnae", " (the Itgg ..... ped things) lay be_
'OOOandl,OO'C ,fie< 'boul 15 m""'tet d,.w;ng "P Ihe /i ... 'he
r,.ebed being obou, 7 i"ch", ",,,. The ...... 'ew o'her guides. Thu
lowe, crllie.llempe,.'u .. ;' In oIlng rate (wi,h lhe same degrea
of agit8lion) ;1 ""IV linle diffe,enl from Ihal of wate,. Balow 400
C. however, Ihe oil cools tha work vary mucl't llower. Using" ,est
rig. It was fouod (wilh slill, unagltalad Huids) Ihel water would
take aboul 3., secOodl 10 riKIuce ,he lampemIU,. 01 a standard
probe fmm 10 and oil al>ods a Suitable_ For water, JUS! pr>u,
It away .nd ..... Irnll, Bri ... m.y be kltPl longer U" pI ,1C conI
......... no! m".1) ..-d l!>en fl ... shId -.. Itl' "nk wilh
pl,nrv 01 w.t,r. It Ihould IISI , long lime '''\''WIIY Oil I. more
predo ..... .-.cI eOllly, bul .impl, '''einer ca" be used to r,mOve
the dirt. KHP. lid on the oil-beth when not In ...... I Il.-.cl
Ihat even .fl" Iwo yeatS my own .. Idom I'IHdI cle'nlng. 1.-.cI I
.... 0;1 n'IOnI Ih." mosl model er9neers. The ",ope< oil should
be uled it " ,11 POMibIe There .re VIlioul IJI"ades. .nd .ltCh oil
eomp./lny .... It, own. I use fI.P Que.-.clila An". though Ihe'O
... el'd,l. 19" i. "mOSI as good .nd eheeper, h 1$ u"'onun.,, Ih"
the .. oil' ,r, no longer supplied In lhe old one gallon lins. bY!
25 I;". (about 5 gallonl drum can be sh"td bitw .... triendl - .nd
400 litre drum could be che.p .. l1ill lor club purell ... ,
failing 11 1PtC1" 011, good Oil" of .boul SAEIO 10 20 vlt.eoslrv
will serve. flul NOT mOIOr oil, whic:h blended fOf quile dillerenl
servic. and chlr,eteri.,ic.. and mOSI NOT "used' II'KIlor oil This
.. downrlllhl dlngoelUl: il can corm,;n up 10 25')(, of the tlNvi
.. IrltCtions 01 peuol end can Il.sh 011 ;"to. furlOU' fire if used
lor quenching hol m.lIl. The .1 .. 01 Ih. Quench balh muSl lICCOtd
wilh the si" I.nd qU'nlily) of the work p .... sing thr of hot
metal 11 0 ....,;d und ... t'mpe'.,Ur' .... A h.II_inc;h ,001 5
Inc"" long w.;g/tl about O.J5Ib. for lhe odd I;In", punch and
,imila, small cuu,' iolIIl kelP "GOIcIon SY'up" lin. " 'h'" hev.
good lids. bu, fo, serioul wo,k plastic "builde,', bult the wire,
;n lhe bud .. , be ... r In rollry II'KIlron I 11 ..... end yOU
should nor try ro get away with .n inadequ31e volume 01 coolant. In
Indu.,ry. of COUrN. lV5.em, 01 p'\Mlle".. underwater jels. 1.-.cI
so on r. uSlPOnl i, clean ' hold 1110 ,he light uOl il lhe colours
,un up 10 IIm"". lhe poinl. ThuI ,he poinl is hem lrod ' emperlld.
bul lhe main boop, and you ...... slill be able 10 oblain Ihe
wecial l60C. Again, you need a subll.anlial conlainer . and t use
.he oule. v8s.sel ' ,om an old-fashioned glue-pot, Fig 20 shows Ihe
sel Up; Ihe old boiling nng I picked up a. a sale for a few pence
finally gave up. Ind you ..... the pot here on 8 replace ment.
Ordinary mercury the,momelers. usually nitrOgen tilled, are
available which go up 1o 400C. and Ire nol e.pensive -lhey can De
had from labo.atory &Gulp-menl $YPIlliers, 0. o.dered Ih.ough
your local ph,rmaciSI. Alternatively thl well-known "Rotolherm"
dilll thermomeler. can De used. 8uI ",. mOSI of our wo .... an Oun
.hermomerer from a scrlPped cooke. will go up h;gh enough - lhough
11mev De marked in hhrenheit. The salt 5 ,.e markeled Ih,ough Edga.
Vaughan & Co. , Legge Shee. , 8ir-mingham and it may bft thal
t>y the liml Ihls book Is publi.hed Ihe usual model englnee'"
suppliers will mar1(e. Ihem ;n .a.he. s maller quantitoes. 100rect
$Ypply t,om Vaughans may involve "Club purchase"). There .r . 01
course. a numbflr 0' brands. bulthe only SO" I hl"l uHd I. Ihe
DEGUSSA type TSt50!ASt40. h COmll. es a powder m the consislency of
domestic ... n, bol must bfI kept dry, as il can absorb moisture
lairfy quickly. It is non_loole, and lhe only .... ious haza.d is
th.I, like some weedkillers, If absorbed inlO woodwork io. vour
overalll! it IUPport. combustion" I deal wilh "S.fety in hilt t
realment on PlIge 102. 1ft(! 01, will be suffid .. m n... piece can
I .lIowed 10 ,;'-lrle Slraw reaches Ihe 'egion of Ihe cunin.g edge
Ihe tool is quenched, poinl down. in wale. The vlnul of Ihis method
is, as I have a!ready suggesled, Ihel Ihe heat lravels down insjde
Ihe melal . and we can be lalMV sure Ih81 .he ,empering Ims
,e&aciangas in .he "" of bulning. N'turally, \'OU musl 'ccounl
yOUr ... ,roundltlQ. 11 IS \'OUt hearth' lint I1 will h .... cooled
IlIrough the critic.1 tinge ... '" "owly and cln be M' the .. hpen
to l ini"" 011 Some books ""liI\Illt l l>&tthe,e mlV D< a
lendlncy lo"""d, bolh scaling 1,-.1 dlcatbu,i'ltlon wllen uling Ihe
smilt, hearth. bul ,10,. need nol cau"" us 19Iou, ,nd some f .....
wrll ""'" "sh.tpeoIo: 1.Jme. Using 1hI - e ...... 11 can IHo
Ihronled down, Moreover, .. lhe will be heated la,geIy by radl.,lon
from hot Ii'ebtick it " Flo. 21" _ ... _. ___ " . .... _ T ......
___ ..... " .... __ ... ...., ... " ... ----_... ...---... be ....
l1ed more .... enty. And. finllly. ,\ we have _., pitcH ID h.,(len
' .... n_ Cln ....... .. bIa amount 01 illS The "uve" ill ,pity
.'i"" fu,n..::e. The intelligenl uSl 01 firebrick wiD bot' ""''''
01" and .""''' mor ......... "".tino use \h, .. type .. First.
ordinary fi"b,iCII, f,om I to 3 Inc ..... In thidness. These are
,ehaetory ,,,he, ,h.n hu, ins"lato,. Ihev ... 111 ... llh.,.nd verv
high t.mp.,.,,,.... Seeond. lighlweight "lnlWl.tinog B,k", 01 ...
hieh "Fossaki l and "Fol ... in" ... tvpic.1. These i0oi< feel
lik, con. Ind .re inteoGed lor .... at inwlltton behind will, of
Ii'ebrick in fuMIC ... They ean IHo 11 lOOOC., 01'>1 .nd .nd
deed cold I1 , .... 01 ...... _ and . " ..... bablt In I
............. ail" IS firebtid. 80lh IIfIbndt Ind insulat .....
bricks can be hid ffom most builder. men:h"n,$. The third tyf* ....
"HOt Fac." bric:Idlld - lhe Ak:ost Pon.bIt Forge. F'og 2S Intended
for " .. by 111o .... te f ...... IbroecI. il an filCh up to 11 5OC
Ind i, very ,,,pid in ""ating up. Onct up '0 tlmpe,"ure the supply
can be I"'UC'" - Ihl lull hut output i5 Iqulvl-lenl to .bout 1 6kw.
The,. i. no pv,omell'! Ind tempe tu,. must be Judged by c:okJfomblr
;. .bout 7 in 5 in x 7:i in .nd il can be fi,ed on N.Su 9i's.
P'OIHine, or BUllne Fig. 30 The,. I .. olhers. of eou .... In
vlrying dog,,,,,. olllOllhll1it8!ion ,nd si.e. ... ho P .. Clls.s
Ihs I" 01 en.mellinll lor IIDm. tvI)eI 01 pa"'ry. IOf th., matte,)
will hi'" I\>Ch lurn,c. whic:h cln u .... ltv be " f". :MI
'''''lM""''' , ,. in""'llng" Ilmesl BYI He Ch.lX. Tub40 Fu ..... c.
M051 01 mv own wa,k 11 done Ill"" In In old ,I.cltic muffle 0<
... 1'1 bath. but 1 do make hlMluenl UA of I rigged up .. r"ed l
uboo fu,,,-, shown in Ppg. 31 The tube il"" il pi,,, 01 '-I inch
UhlU11 pipe, relic of !h, dlyl w!>en 1 u5ed "p.ope." 11
'vlntlg.) mOloough .... ma. I.., ,he surface to Improve ,he
Ii.,;sh. W." thid ca... ,her. Cln be , dimentioe is cril,c.IIG
w,'",n 10C, The m.1I1 muSl be .... ated oIowtv Ihln "Io.ked 11 'h
nn lln\l tem"","y" 10' one I'rou, "", Inch of Ihickne.. In lhe
caS!! 01 recl8ngul., seCtions the ,mal ler dime"!ion is IIk.n,
11Il>oold Ih'" bor cooled ... lowIV" ctn boa COII!';ved, l!
heated ln a mulfl e wi,h good heat In.ull1ion '0 Ihe ch,mbe, 'I m.y
bor ,I!owed 10 cool down 11'1 lhe 'umace, OlherwiS!! ;1 mu", be n'
in ho, a.,," or -". 'im!hr, "'1I!eri.! which w,ft .. "in I ....
helt Thin. lIal saclion\l can be (0111. d belW"" rwo pre-lIl1,ed
1nsull '''"II The highe' the CllboI, conrenl , .... MOre imponanl
is ,he slow " .. 01 oooI'ng, F ... '"mild"" IIHI lhe piece mlV be
coolld in ,i, once It has dropped 10 .. ound C..bon. " T ..... p.C
B.lowO 1 0 1-03 0305 05-0,7 07_0.9 Abmr.0,9 92()"900 81()"830
850-800 B20-7BO BQO.780 790760 Sihr .. StHI' 770C " f ig 40 , __ '"
... " ..... ___ .. - " ............ , d ..... 4OO*C, but il f'
inadvi ... bIe 10 quench 11......, f,om Iow le"-llu, . No,. WOtiI
nw., be fully .".he.led beloIt llIe 1001 mull ,.m,in &ha", Ind
t.enc., III,d OVer , long penOd - and 'flY Iou of sharor- c.n be
1.1.1 10 llIe ,IIICI"'-&s of the won. 'fhes.e lWO rlQuireman,
s. !!nUI g,.,n ,ill .nll ml.imum hardneu. c,nnol be .chl ..... d
witll Ih' norm"1 carbon 1001 steels lend , ... ,n IISI 10 with
IIlgh-lOlliI and lhen hold I1 I ... the ft,m, III !he I.mp un1il
,he oil Ignlt .. , ..,gn .. it doe. 10 mow It IUnduclor. 10 Itlat
ampld A-B. .nd Ihe lize of . 11 is IefI thera 10< lenglh 01 time
which depends both on lhe rype 01 st ... Ind its thickness; 10
minute' whl ",me. "" even tile he""', lIOt'ng nd 30 minules is
.lIlket would be I'IHIded 01 hell t'"ling ........ largtl cranle
,ond ". upaclty of Ihe m,jO'ily of eno"-.... To begin with. lhef 11
co' side.able yari"ions in "toy .;:orll enl ',ngi"", from 0.5" 10
1.00Ii CIIrbon. 10 4.00Ii Ch.omium. 0 10 18% rungsl"" and oom. with
5" Cob.II -.nd Ihev m'Y vary.ng PlOpOnionl 01 Molyb-.nd Vanedium IS
well heh I ""aunenl ,nd an nol good enough - ,i,he, cr.ck Of it win
nol be herd '0 I .. nge by- I.ir!v ouick heating
Of 1300C depending on lhe MOSI Cln lhen be cooted in '". IOMI
'Oacl .n.lysis i.lr.nown, and lhe worto:shop has precise
lempe.llure control 01 lhe fu.n.tt. this WOfk is btrst ,,,11 10 Ih,
specl,Ii". Eyen h" will orobablv decline Ihl work unlus Ihe source.
IVpe. and gred. of metal I. "acTty known. " CHAPTER 8 The
Measurement of Hardness I, Is 'hi ' mlny model engineers will h.
con,.rnld w"h ,he .,lu.1 me'SUr,menl 01 hardness, 001 il 1I helpful
'0 know HOW 11 is donot w"-" faced wilh one or other 01 ,he
........ 1 "h,rdness numbers" uHd. The ml,n d,ff"tC\Ilty is in deHd
one wtrlch dilt'ibutn lhe ..... 1 sideways ,.th .. Ih,n ...ruc.11y
or ",t poin!"' The OII"I'j>Id mulfte referred Tp on Plge 57 it
normlllv uMd on Ihe Ulile brlzlng I>"rth_ which 1>.. I fi ..
a"ngle ptOPDne bu ...... il should not be tnOfl Ih,n 8 in. long
p.herwI .. IhI MI1'ng no. be unik>to f>OmIel twin pore ....
in jolnte,. Make su" tIIIt Iller. la no rislc 01 any PiOn of I""
bII., w"l touching .nything . nd sel ell on pieca 01 firebrick. Use
I)ILI\I wi.h 13 .mp fulll Ind swllch on. DONT TOUCH ANYTHING. Afl
sl>on while lhe lube IIhouId 111eed . ,nd Ih,..., make up c"sing
ollnsul'ting brick.! carved out. feedi"ll , he W"" OUIW''''"
belween twO bricks. Makp terminal bIocI< "om t in. Synd,nvo end
fill Ihit 10 one 01 the bricllll mull be earthed. '5 mU$! m.
PlOIKlive W/et .,.....,. ItIe lerminals if 01 .... 111). How you
'.LCIUM SILICATE l/4'mr.All ROUND 'I' 'f> 0 .. (KAOWOOl HIGH
DUTy) ,- 2.1/2Jedded in Ihe lace. AI fi'51 sighl Ihese woukl Mem 10
be Ih.lde.' module fOI Ih. of , Ima\l There II el ... a vitiation.
wi,h Ih' in lhe lorm 01. hollow IUt... mekl"lllhe basi' of Iubl:
fumlCe. The are 'W'O probIl"'. !he fltsl 11 thll lhe unilS ....
wound lot no mora Ih.n 60 IIOIts .... IhlI e;lhe' e helW I.e""orm"
11 needed. Of .,.,. musl u" four unilS. The 5ICOI'\d Is rhll lhe
hp, lace 01 lhe bnck!; will nol CI'IY "'V Iced VOU would need
auppor!ing end 'ne" ,,,n lIII.enl "00m .... , .. gI_ wm, Th.,. hII
.... little side--plec.s Ihlt 11011 thi"'" lrom comi"lllhal way.
arid can be worn ""'" .. They "SId be Quite hol. 1""-e ffective
cold Jut'>Ction can bI .nov.d 10 Ihe m.'I< .ltlle, by
usil'l\ll .1Ioy _ifI\lI c.tlllllcalled I .. compensati"ll IeMl")
CIf more limply by conl,nuing Ihe llIermocoupll ellment .we from ".
tighl t hrougl'110 M ,nd R, This is the mllhod I UH, lhe ""', ...
need not be .11 1"'1 I. aw.,. from lhe fumace . nd one h .. 10 buy
Ylld or SO of tt.ermocouple wire .nyw .,.. The /un, " A , , , " , ,
, " .. 202 258 202 "" ,,' '" 527 '''' '" ", 663 801 6.1 3 "'" ,
should be I fal"" cion fil on 1"-inwll lOB. Thi' will prolecl Ine
coupl. f.om knock nd llso (In 11>, c .... o' Ih, Nil poll from
ge ..... will ell''' I I,ma-tag in 11>. ifldicalionl I'0Il'
Indicato. wHl land 10 ",ad the l"ml1l"l u , It was J ow heavy I'"
lube it. There ;" no need. 10< our 1)1.1'1>11181. 10 1'"
II,inl..a 11 ... 1. Once ele'r of lhe 8etuII'um.,,, tl>' wir ..
mly be in,ul"ad wltl> ordinaoy 1l_lng. er , likely 10 11"1 hol.
Such 11""inll etn b" ob .. ,ned lor otdefed) 1h ...... 1l1>
radio ... rvice .hops. Th. Indicato, . Th. maximum .".ding "ling
Jron..conlt,n"n wdl be about 50 milll"oI". and lor 8$1827 Nie.-
NiAl, ,boul JS mY. 11 I'0Il ha", a "multimll'''' will> I
milliVOIt 1C,le. wall and 1I00'I. YOU C.n 1''' tl>il. Olh" rwi
... YOU muSt eilh buy _ or mike 0/11. T""I was a "m. when .....
rpI"'. micro-......... ten; Wlown as 7JS ohm. This Is whe" tha
."si'"nea "R" of Fig. 62 comes in. 11 _ "",k. this lCXlO - 7J5 ..
265 ohm. lhen w ....... a total .. listll". Finally, ca,bon steel
will 'the really ha,d stuff. Until quite recently I1 was used fOf
machining ,ha chilled C8St iron foil. used in Sleelworks (Ihe
aurfaca deliberalely made as hafd as Ihe hard SPOts you can"'
machine On your C8Stinglil and habitually cui hDrdened and lempe,ed
sleel pivots wi,h a carbon "eel graver_ The only dil8d'1antage
whiCh afflictS rhe matenalls thalli tempers a\ quire I low figure.
HSS 11. inillal ..... SoOfter Ihan carbon .teel. (Fig. 66) but
whe'eas Ihe 1811er would Sl8rt to lose some of ils cuning ha,dness
8' about 270 C al the 1001 point Ihe former can be oper.,1I'd 50
hot thar rhe cUl1ing 011 will smoka and. inde&d. I have .... en
SPeCi81 grades ,un for demonstration pUrpOse. cuning al a dull red
h08'. The same is I,ue of Tungslen Carbide: its virtue is 1'101 ils
i. is inlended as 8 FAST CUTTING TOOL perhaps 8"hre. lime. 'he
SPeed 01 HSS. This is Iha Crux of 'ha malte,. You can buv a couple
of feet of carbon 1001 Sleel fOf IM price of one short HSS loolbit
: you can file it. bend It. forge 11, and harden i"o cuI tough
allO'( steel. ""en hard cas' iron: and you can gel superb 1001
finish on rhe worIt . aur you MUST keep Ihe CUlling speed down and
keep the 1001 point cool. For roughing cuts ' ha speed ","",uld be
aboul one Ihird Ihal used for HSS I,hough if Ihe COOlanl supply is
good you can rry fasle,) and for normal finishing curs ,he machine
should be run at abou"w" ,hirds Ihat used for HSS. In facl. for
bfas. '" """-cutting mitd eel . laking modftl engineers' finishing
cuts. 'hera may be no '" "'" -8r SlIII; we rely enllrely on the ,,.
"1001 Iln;!IIl" I", the decoraliv. reflective SUrflCH whOch Ire 50
much admired. Ind ......., go to lhe 01 lapping lhe culIl"" edge
with rouge on In iron liP' Wilh Ihe ever-Increasing COSI 01 ,11
alloy lleelllend HSS in PIM!eular) il does some sense to reconside,
Ihe ollC' 01 Ih, 'oId flllllionl8 worllll. I would not of COO'H.
suggest Ih., w. aben!ion HSS wholeHle, Ih., would be foolish But
/of """at It is worth I wilt conclude thiS not, by wl:z,nring Ihll
Al l Ihe c nkshlft. I have made. end thlt is quill I lot. hive been
finished. In(! mo.t of them ,oughed. using clrbon 51"'looIs on the
crlnkpins. Ind mosl hive been lurned on lhe jou",," ''''1 wIlY IS
Why nol g;"'" I1 Itl,,/ APPENDIX 3 British Standard Steel
Specification Numbers The Old Brit ish SIIndard 97&1955
characII'io.ed by 11>8 "EN" numbers which many of uS 51ili UH.
wu ,epllced by Ihe ","w BS970 in 1972, h re.11y is t>mlllh't we
stifled 10 uM ,11 It h.. one gore" Idvantage. in thlf the BS numbe,
i,sell g;ve. u. ,h. cafbon conlent ' 0' many steel . The numbe,
COMprises Ih'H dig" . followed by I !ener. loIlowed by rwo mar.
digils. Th. fr"l 'h'" digit. "rv. twO purpo .... They lIiye b,oad
Indication 01 11>8 TYPE oI,teel. thus -000 10 199 '" all
--pl,in- cerbon .teel With some m.nea""' contenl 200 to 240 "e
"F,ee-cuning" "'e",ons 01 the above 300 10 '99 a,e III 'S'linleu"
0' "Hu' Reslsling "eeis 500 10 999 I,e In --Alloy" lleels and
wilhin Ih, number Ih. mlin .IIOVir.g ,'emenll cln be Id.nt,fI,d. W
.... concerned lfor ..... t".,men,! only wlUI the pI.in Clrbon
Iteel. .ncI, pemlpl. their I,u cunlng 8QyiVllenl. The first dillll
nn be ;gnorad; 0 .nd 1 "plaln" end 2 m .. n. "frH-CUlI ing". The
SKond lWO dlglts. Ipr&ceded by 0 0.- I J g;ve 1"- "'Ing'''"'
conlenl myl"plled by lOO; thu. 145 mIIanl 0.' 5" m.ng ......... If
preceded by 2. Ihne digits Indic81e th. sulp/>u, """tenl.
&{IlI,n, , 100.22. will be I O,2' !!Ii Iulphu, 5t ... 1 The ..
con!! group 01 IWO digi ls Indicl1es ,he c.fbo.-t conllnl
multiplied by 100. Th", '5 indicate 0, ' 5" ca8g8 I B Ih.tll thould
be "",m.,ised It.round 880C. The speCifit:lll_ doe. no. COW<
'Tool Steel.", with m",e Ih,n '" ca,bon. APPENOIX4 Approximate
Conversion of Hardness Scales (ASTM Conversion Tables) (FOI'
Sleels) SHORE VICKERS ROCKWElL "" No. '" "c" 1000 lbffSq.in. " 1030
" " '" " " '" " " '00 " " "''' 66.4 " '" 65.3 '" 820 64.7 "' '00 "
86 "" 62.5 SA '" 61.6 82 '" 60.5 '" ,'" 59.2 "" " '50 57.8 '" " ""
56.8 "" " '00 55.2 '" " ,SO 54, 1 28" '" "" 52.3 '" " "" 51.1 '" 86
'00 49.1 20" " '80 4 7.7 20" 82 "" 46. 1 "" " (For Sleels) SHORE
VICKERS ROCKWELL "" No '''' " C' 1000 lbl/Sq.ln, '" '" " '" " ""
43.6 ,,,, " "" 41 .8 '" " '" 40.2 '" " "" 38.8 "0 50 ,SO 36.6 "0 '8
'" 34.9 '" " '" 33.3 '" " '" 31.4 '" ., '00 29.8 '" ,,, 280 21. 1
'" " '" 25_6 '" " '50 22.2 '" " 200 20.3 '" Rockwell "C' is nOI "
220 15.71958) '" applicable below lhi. " ,,, 13.4193.4 81 " range.
Rockwen "8" 28 "0 8. 5189.581 " in br. ckelS 28 "" 6.0187. 181 SA
,. ,so 0 181.78) " 22 '50 178.781 " 20 '" 171 .281 " " '" 161.68) "
The .... conversions musl be u$OO wilh discretion. especi811v as
regards ... Ultimate Ten.Ho Snenglh column. TheV relale onlV 10
C.rbon and low alloy 11HI. and ... clude "Slain le"" sleell. '"
Glossary of Terms "-1.5.1 A.SM E. A.S.TM Acicular Alloy 5'H'
Arm"aling Arrnt point A".'empering Aulleni'e 8.SI. a,inna BiUet
Bodv Cemred Brine C.st St .. 1 '" ........ enc ... Iron and Steel
'ns','Ule. ""'_"" SocielV 01 MK"-nicI' Eng;neoers Ame
