A RT O F SA W- F ILIN G

S CIENTIFICALLYTREATED AN D E"PLAINE D N PHLOSOPHC LPR NC PLES O I I A I I .

WITH

AND E"PLICIT DIREOTIONS FO R PU TTING IN O RDER ’ ALL"IND O F W F RO M J WLL R S SA S, A E E E S S AWTO T M - MILL A S EA .

L TR T D BY F RTY- F R N IL U S A E O OU E GRAV INGS.

Y H . W. Z I O LL F , ’ ’ “ - " AU THOR OF THE OABPENTE P S AN D JOINDP S HAN D BO O ".

NEWYO R" J O HN WI LE Y

15 T OR PLA AS CE.

18 7 I . Ent acco d n t o Act of Con r ess in th e a 1 864 b ered r i g g , ye r , y J O HN WI LE Y

’ "n th e Cl erk s Offi ce of th e D istri ct Cour t Of t h e U n ited S t ate s for e ou th n D s t t O f N e w Yo k th S er i ric r . g zyga

RAI HEAD n. C G ,

S t er o t r a nd E l ec t r m Prim er , e ype , y per ,

G al l o n Bu l lh mg,

a 85 C en tr e S tr eet. 81 , 83 , d N S CO NTE T .

O rigin an d u tility Of th e saw First saW

h n t on O f th e Principle Of t e co struc i saw . Pri n ciple O f th e cross

Cro ss - cut saw for soft

- f r m d m oo d Cro ss cut saw o e iu W . Cross - out saw Pitch O f t h e Cross - cu t t imb er- saw Back Back- fo r The fle am

Bil l et or b uck - saws Billet or b uck- saws for hard

The t oo co mmon saw . .

Longcross - cut or log

Pat en t h O Ok - to ot h

Cross- cut circular - saws Cro ss- cut circular - saws for so ft Cross cu t circular saws for hard wo od Pr unin g- saws iv CONTENTS .

ol web an d om Scr l, , c pass ’

r aWS o o o o o . o Bu tChe S s O

’ Surgeon s saws .

k- s for n o b etc Hac aws , sawi gir n, rass , Prin ciple of the rip- saw Han d rip - saws V ertical mill- saws Circular rip - saws

f O f t t for - Di ference ee h circular saws . Ex t o O f th e d v o of to d plana i n i isi n a circle in egrees . S aw- settin g

he ot - n set T cr ch pu ch . Prin ci ple of th e Aiken se t The ol d way o f settin g Sel ection of saws an d o ther IV ERSI

A RT F A - F ILIN G O S W .

R G A ND L YO F THE S A O I IN U TI IT W.

THE S aw is an instrument O f somewhat an

e n cient origin . W cannot ascertai precisely when the first saw was made ; but it probably followed the more common and primitive tools

- the hatchet, the knife, and the . The in str u first saw was, no doubt, a very imperfect m ent in comparison to those Of the present day. S till, it seems incredible that such elaborate works Of art as we read O f among the ancients should have been constructed without the use

Of the saw. The Greeks ascribed the invention Of the saw Dcedal u s o r to , his pupil Talus ; but it is se o n certainly more ancient, for it is repre nted the s o f t Obeli ks Egypt. It is a tradition tha - 8 THE ART OF SAW FILING . the prophet Isaiah suffered martyrdom by th e

saw. “ There is an ancient book, called the As " en sion P c Of the rophet Isaiah . It says “ Then they seized and sawed Isaiah the so n sa Of Amos with a wooden w. And Manasseh

‘ M el akir a and the false prophets, the princes

o n . Bu t and the people, stood looking Isaiah ‘ O said to the prophets who were with him, g

t he O f S do n L ye to cities Tyre and y , for the ord ’ hath mixed this cup for me alone . Neither o r b ut did he cry out weep , continued to call o n the holy ghost until he was sawn asunder. It may be in reference to this circumstance “ t S t P hat . aul says Of the early martyrs, They were sawn asunder. o f S The ark, the temple olomon , and the o f ruins buried cities lately exhumed, would seem to have been impossible without the use o f w the saw, although we kno how much may be accomplished with very rude tools when time and patience are not spared . We do not find the saw used by savage n a it tions, as, without the tools and skill to keep in order, it soon becomes useless . - THE ART OF S AWFILING. 9

The knife and the hatchet, more barbarous o n weapons, can be sharpened a smooth stone ; ff but sharpening a saw is a very different a air.

saw- m il l o r The first , saw driven by power, o f which we have any account , was erected in the Island Of Madeira in 1 420 the next at h B 1 432 . reslau , in Austria, in T is was fol lowed by many others all over Europe .

The saw is now an indispensable instrument, an d is in more general use by all classes Of mechanics than any other . It is difficult to imagine how we could dis pense with it for a single day—from the burglar who cuts O ff the bars Of his cell with his watch 8 pring saw, to the builders Of navies and cities , and the busy mills which quickly fashion the huge monarchs Of the forest into shapes for the of dwellings and conveniences mankind .

THE PR C PL O F O RU C O IN I E C NS T TI N .

THE saw is a seri es Of knives set o n a line ; f every tooth is a kni e, and cuts a small portion

Of the material . Each is kept from cutting too deep by the tooth o n either side ; each tooth 1 ", - 1 0 THE ART OF SAW FILING . should cut its allotted chip or slice Of the n on material , carry it alo g, and drop it the outside . The perfection Of a saw is to cut the fastest o f and smoothest, with the least expenditure

is an d power. To do this, it evident that each every tooth should be so constructed as to do its o wn proportion Of work ; for if o n e tooth only is out o f shape o r o ut o f line with the t nl O hers, it is not o y useless, but a hindrance and disadvantage to the others . Every o n e who has occasion to u se a saw knows that many times it would be very con ven ien t if he knew how to put his o wn saw in order. To be sure to excel in this, as in every a an d thing else, requires practice, correct eye, Bu t steady hand . we contend that any person o f ordinary capacity can easily learn to file and o n set his w saw . There never has been any theory o r prin cipl e laid down by any good authority for this t par icular science . Each person has had a o r theory of his own , and followed that ; , more n o at likely, has had theory all, and did it at o n e wa random , sometimes y and sometimes - 1 THE ART OF SAW FILING. 1 a t no her, never twice alike, but generally very f unsatis actorily to himself and all concerned . Now there is always a right and a wron g way to do anything ; and if we can establish

in a theory this little book, and demonstrate its m correctness fro scientific principles , and a r trial shall corroborate the demonst ations, then the Object of the author will have bee n acco m l ish d p e . We find man y very good m echanics that h u n ave always sed saws, who fra kly acknow ledge that they never could file a saw satis il fact o r . y to themselves , at least The rea son probably is, they never studied the prin cipl e o f the action or working o f the in n m strument . There is no reaso why any an u se who knows enough to a saw, should not be able to put it in complete order ; although — it is more Of a science than man y imagine the u of p tting in order of all kinds saws, from the ’ delicate surgeon s saw with which he takes o ff

- your limb , to the monster six footer, with teeth d like a ragon , that screams in the depths of the forest, devouring trees and logs with insatiate r apacity . THE ART SAW- OF FILING.

When we consider that there are nearly o n e hundred different kinds o f saws of all sizes and shapes, it will not appear strange that we claim

- fil in for saw ga place among the sciences . It is astonishing what miserable saws are l m sometimes used by mechanics, or those c ai The ing to be such . only way they can be coaxed or driven through the is by hav u se o f ing an enormous set, a liberal Oil , and

n - a other lubricator called elbow grease . The dif ference between the work o f o n e o f these saws and o ne in proper order is about the same as that between a hole bored by a sharp auger and o n e gnawed by rats . It brings to mind t he remark of the wood ffi sawyer, who, pu ng and blowing from the “ n o f : Of exertio using a bad saw, said all the saw saws I ever saw saw, I never a saw saw as " this saw saws .

o the r oss- ut aw P r in ciple of the A ction f G G S . There are several different ways in which saws act in relation to the material cut ; the

- first we shall consider is the cross cut saw, by which we mean all saws that cut across the

h . grain . T is is illustrated by the figure THE - ART OF SAW FILING. 1 3

1 o f Fig. represents a log wood seen end o f h wise, looking at the ends the grain , whic consists Of more or less minute fibres or threads o f which constitute the tenacity the wood . O ur object with the cross - cut saw is to sever these fibres or threads ; and as the material is n on - o r u i ou t h elastic ny elding, we must eac e fibre in two twice, so as to leave a small groov o r loa f as we proceed , so that the material will n o t bind or pinch as the saw passes throu gh the stick, owing to any inequalities in the blade of the saw . 2 Fig. represents a section o f several saw

of ff w n ff t teeth di erent , sho i g the di eren - 14 THE ART OF SAW FILING .

depth to which each tooth cuts . The n ext tooth to each of t hese o n the saw being t he d ed the other way, will cut to same epth , and form . a as deep as the teeth reach

o n in into the wood, and so succession ; each of as pair teeth working independently, except they keep each other from taking to o deep a hold . A saw should be filed so truly that it will show an angu lar groove along its whole length o n the edge

. 3 fi n e l like Fig , so that a needle wil Slide t he whole length of the saw f without falling O f. A lthough the form of the edge of

Fig. 4.

3 the saw is like Fig . , it must cut the groove

4: n ot . 5 like Fig. and like Fig , the ’ shape of the saw s edge . The cutting is all done with the outside o f of edge the tooth , so the real Operation the 6 o ut tooth is like Fig. ; the wood crumbling - 15 THE ART OF SAW FILING .

i F g. 6. from point to point Of each tooth as the saw moves . — Now the sharper each tooth is that is, the

v o n at . 2 more be el the point, as shown Fig , the deeper it will cut ; but it must not ou t any deeper than will crumble o ut across to the point Of the other tooth . This is the difference between saws for soft o r hard wood ; if a saw to o o n for hard wood is much bevel the point, it will score deeper into the wood than it can o u t so carry the chip, that it will keep moving n o t up and down in the same scores, and accomplish an y thing. for It follows, then , that soft wood we may file the back edge o r point Of the tooth quite i o r beveling, wh le the harder tougher the wood the less bevel we must file the back o f th e tooth ; for we shall see that the bevel of the - 1 6 THE ART OF SAW FILING. back Of the tooth governs the bevel of the point . Let it be understood that the bevel O f the cutting edge o f the tooth is the same for all

- c t a bevel o the oin t cross u s ws . The f p is the i an d dea, is governed by the angle at which the file is held . This is illustrated by the fol

in low gfigures .

7 . Fig.

Fi a . 7 of , g , shows the position the file for a cr o s - saw o s cut for soft w od, such as , bass

W . ood, cedar, etc 1) S hows the shape of the tooth , and c the b evel o f o n the point, consequent the posi t O f of ion the file and bevel the back of the tooth. - THE ART OF SAW FILING. 1 7

There is no difference in the a ngle of a large o r small file ; all the difference is in the fine o r o e coarse cut f the file. W should prefer a f an d a o r good sized file, not less than our a h lf , " fi ve was inches, if it cut equally fine and sharp o n the corners .

- h In all the following diagrams Of saw teet , the point of the saw is supposed to be o n the e d l ft han .

a . 8 o f , Fig , shows the position the file for h saws for medium wood, such as c estnut, bay d l b woo , black wa nut, cherry, etc . ; shows the

h c s ape Of the tooth, and the bevel Of the point.

a . 9 , Fig , shows the position of the fil e for 18 - THE ART OF SAW FILING .

9. Fig.

o ak saws for hard wood, such as , ash , ,

. b the , , etc ; shows the shape of

c . tooth , and the bevel of the point It will be seen that the bevel o n the pitch o r cutting edge of the tooth is the same in all the above examples but the bevel o f the point f looking the length of saw is quite dif erent. The next thing to be considered is the angle o f the pitch or c utting edge Of the tooth Of a

- cross cut saw .

Let a . 1 0 , Fig , represent a board, across which we wish to make a deep m ark o r score S with the point of the knife . uppose we hold n o f er eiidicul ar b the edge the knife p p , as at , it

n ) t ut is evident that it will push harder, will c

20 - THE ART OF SAW FILING.

i to ou t relat on to the material be , also the pitch — o r inclinatio n Of t he cutting edge if we combine all these we shall have a perfect tooth .

n . 7 8 9 It will be see by Figs , , and , that we hold the point O f the file towards the point o f saw s the . Many will contend that a aw should be filed towards the handle, giving as a reason that it prevents the feather o n the cutting edge o f r O b ec the tooth . This feathe edge is no j tion for every saw after filing Should be laid down fl at and both sides jointed o r planed o f down , so that the cut every tooth shall be n exactly o a line . b e This should done with a long whetstone,

r fi n - o e cut file with straight sides . This takes O ff al l an d the feather, makes a finer edge more cutting surface ; for if a saw is newly o n set, and not jointed the sides after filing as above, all the cutting surface is the extreme

o f scr a tches point the tooth, which only and does n o t cut ; it is like markin g across a board with the point of a pin . a 1 1 of as , Fig. , shows the point the tooth it is left after filing ; b is the same p oint after - 2 1 THE ART OF SAW FILING .

1 Fig. 1 .

i - joint ng the sides, making a real knife edge, and not a mere scratching point .

And further, as regards filing towards the of e wa point the saw . W cannot any other y get the bevel of the teeth , as shown at Figs . 7 8 9 , , and , as will readily be seen ; and still u f rther, every one knows how much stiller, smoother, and with less vibration the file runs o f when filed to wards the point the saw.

The r oss u t Hn d- w C O a S a . This saw is more common and in more

o f general use than any other saw . They are v m - t o arious lengths, fro twelve to thirty w inches .

1 2 Fig. . THE ART A - OF S WFILING.

This saw for soft wood shou ld have about six teeth to the inch , and be filed about the 2 . 1 bevel shown in Fig . G ive the teeth a full set, and joint the sides thoroughly . We would say here that the first thi n g to be done in filing these saws is to see that

o n o r they are perfectly straight the edge, , if anything, a little the highest in the middle . This is very import ant ; for if any tooth is o f shorter than the rest, course that tooth does n not cut at all , and is worse tha useless, for it gives the next tooth more than its share of the to t work do, and consequently it is imperfec ly done . P the an d lace saw in the , with a fine

- n o t n t e n n single cut file, less tha inches lo g, file the teeth squarely down till every one is touched . Next comes the setting ; the princi ple o f setting and the best set will be cou si " “

t . dered hereaf er Fi nd /f w P a 5 0 f"5 S e e that every tooth is b ent to the full o f capacity the set, for some Of the teeth that off w t are filed a good deal in , ill wan - THE ART OF SAW FILING. 23 a much harder blow than those that are only just touched . saw n The should be placed in a stro g light, so that it will be easy to see when every toot h is brought to a point . Be careful and not give a single stroke Of the file after the tooth is brou gh t to a point ;

n s that would be worse tha useles . If you can not get the right shape Of every tooth in an old saw without filing too much , let it be till next time . It is better to let the imperfect o n e tooth wait its time, than to spoil a perfect in trying to make it correspond with the im

0r oss- 0 u t Han d- S a w or M ediu m ood f W .

i F g. 18.

This saw should have about eight teeth to 1 3 the inch , and the bevel shown in Fig . . This is abo ut the thing for mitering soft wood 21 ART - THE OF SAW FILING.

e o that is, the bevel . The t eth may be as c arse

. 1 as Fig 2 . It will pay to have a different saw for diffe r rent kinds of work, both in wear and tea o f patience , and excellence of workmanship . Those who attempt to do all kinds Of work o f with the same tool , will find most the time that they have not the right kind of tool for

any work .

I Out Han d- S aw for Har d n.

14 Fig. . h This should have ten teeth to the inc , and

the back Of the tooth filed square . It will

mitre soft or medium wood well . The bevel

o n c o f the pit h all these saws, it will be seen, f in s is the same . The dif erence is the sharpnes

o f the bevel on the point.

- b - Cr oss Ou t Tim er S aw.

an d This should have four teeth to the inch , - 5 THE ART OF SAW FILING. 2

. 1 3 filed about like Fig , and should have plenty of set for wet pine o r S pruce timber . i k- ws Bac S a .

A back- saw has no advantage over a hand o f saw, except in the thinness and lightness the plate ; the back keeping it from spring o r ing bending .

on They should be thinner the back, so as to need no setting.

Fig. 15.

1 5 of - Fig. shows the kind back saw for soft to e as wood, ten teeth the inch , sam bevel

Fig. 12 . 26 THE ART OF SAW- FILING

- . 1 6 Fig is the back saw for hard wood,

S . twelve teeth to the inch . ame bevel as Fig 4 R . 1 . ight for mitering soft or medium wood S ometimes a back - saw becomes crooked because the back is loose ; if so , driving the b o n ack firmly will straighten it again .

The F l ea - m Tooth S a w.

a;

This saw is filed extremely beveling, so fl at much so , that the saw must be laid down n to be filed . No set is eeded, and the blade must be thin and o f the best quality and tem per O f cast steel . The best way to alter an old saw to o n e of off ol d a these, is to take the teeth cle n, and begin new.

- 28 THE ART OF SAW FILING .

1 9 - or Fig . is the buck saw for hard dry

o r the wood, five six teeth to inch ; teeth

n square o the back .

B - uck saws should be well strained up, so as u to ring sharp and clear when str ck.

T e T o h o Com m on S aw.

o f t o o Fig . 20 shows the kind saw common to need a description . It is used in all part s e of the country . W cannot recommend its adoption .

- o - w LongGr oss Gut or LgS a .

saw co n This is to cut equally both ways, sequently the shape Of the teeth must be dif fe r n t e from anything we have seen . This saw o n t the too h edge is made the segment of a. o r n large circle ellipse, because the motio

t wo . easiest for men in sawing, is a rocking or - THE ART OF SAW FILING. 29

21. Fig.

i al l swaying motion , bringng the teeth suc essi el c v y into action . Fo r hard and dry wood , file the teeth less bevel see that every tooth is in line with the

m o r . others, whether the line is ore less curved " - The P a ten t Hook Tooth Ur oss Ou t S a w.

22 Fig. .

M anufactu db Wh l M add n n n M a d Cl m so ddl t o wn N.Y re y ee er, e e , i e , 30 - THE ART OF SAW FILING.

This saw is constructed o n common sense

. fi eam s a principles The two knives or , , to I) o r score into the wood ; , the hook little chisel" o u t follows and takes the chip or shaving, o n carries it along, and drops it the outside . t ’ " It ac s precisely like a s , only it acts both ways . The action o f the centre - bit also illustrates the principle of this saw .

It cuts very fast and easy, and is said to be rapidly superseding the Old kinds in the loca i l it es where it has been introduced . a e The cutting teeth , , are first filed up squar , b t h and the hooks, , are lef nearly a sixteent o f e shorter . After the length the cutt rs and u hooks is made j st right, file the cutters ex t r em el m y beveling, but bring the to an edge of and only at the extreme point the tooth , n t then o so as to leave a feather .

- Cr oss Ga l Cir cu la r S a ws . The same rule holds good in regard to th e bevel and pitch Of the tooth in t he circular

- or o f saw as in the . The fibre grain the wood to be divided is always at right n sa a gles to the face of the w. or A W- THE ART S FILING . 31

28 Fig. . To get the proper pitch of the tooth o f this saw o n e , describe a circle whose diameter is quarter the diameter o f the saw ; a line from t h e point o f the tooth touching the outside o f

. 23 this circle, as shown in Fig , will give the o f proper pitch the tooth .

Fig. 24. - 32 THE ART OF SAW FILING .

24 o f fo r Fig . shows the proper form tooth o f t or a large , for large sticks sof

green wood .

25 . Fig.

2 Fig. 5 shows the form o f teeth for hard

n and dry wood . The poi ts may be more bevel

~ than for hand saws . The greater velocity of sa o u t the circular w will throw the chip . O bserve the same rules for small circular

n - saws for finer work as for ha d saws at Figs . 1 2 1 3 14 , , and .

P r u n in ws gS a . These are required to cut very smoo th an d od keen , consequently the teeth must have a go of deal bevel , but about the same pitch as an

- 26 t ordinary cross cut . Fig . shows the bes - 33 THE ART or SAW FILING .

of to the form a pruning saw, seven teeth inch . or on These saws are, should be, made thin th e a so as t b ck, to require no setting ; but mus be well rubbed o r jointed on the sides to take off the feather edge made in filing.

S cr oll Web an d Com ass Saws . , , p

These saws are for a mixed business . They

to - have in turn cross cut, mitre, and rip , and

o r the question is, what is the best average m edium to accommodate all these requir e ments . Experience shows that they should be nearer

- cut - the cross than the rip , for a cross cut will r i -cu t - p, better than a rip will cross . A rip saw makes terrible rough work cutting across the

- grain , while a regular cross cut will cut length of wise the grain smooth but slower. THE AR AW- T OF S FILING.

7 F i g. 2 .

27 o f f Fig . shows the proper form tooth o r

r these saws, though they may be finer o coarser according to the material to be cut ;

finer teeth for hard wood . R h ather a short bevel on the pitch , whic t A l l should be a little less than a righ angle . o n web saws should be ground thin the back, so as to require no setting .

Bu tcher S a ws .

These are for sawing bones, and generally C very h ard and dense ones . utting these is ut of o the question , so that this saw should partake more of the nature of the file . The i n 2 . 8 form shown Fig is the best for this saw . The pitch should be not less than an angle of - fi ve forty degrees, and the back the same, o r nearly so . File the teeth perfectly square across o n the n pitch and o the back . Be very particular about jointing the edge,

- 36 THE ART o r SAW FILING .

28 u . b t the teeth about the same shape as Fig ,

. 29 about the bevel in Fig , the back being square . J o n oint these the side, as it is important to have the bone left perfectly smooth and clean .

Ha ck- ws or saw n r on Br ass etc S a i I . , f g , ,

80 Fig. .

. 28 as These should be the same as Fig , r of b u t egards shape tooth, pitch , and bevel , l b e fo r as the teeth shou d as fine as possible ; ,

of . 28 was said Fig , they must partake more of of n o the nature the file ; in fact, they are m o r ou t o n ore less than a thin file, the edge but not o n the side . These need not be joint ed o n the sides .

he Ri or hittin - a w T p S gS . Having considered the principle of the

- we cross cut saw, learn that its action in rela the al l s tion to the material cut is same in case , n of at that is, the grai the wood is always right an gles to the face of the saw - THE ART o r SAW FILING . 37

In the action of the rip - saw it is quite dif fer en t — - saw . There are three kinds the hand ,

o r - - the vertical mill saw , and the circular saw These all act differently in relation to the ma te r ial cut, that is, cut their way into the wood o n a different angle from the direction of the o r o f fibre grain the wood .

T Han d- w he S a .

i 1 F g. 3 .

a . 31 h , Fig , s ows the correct o f tooth 38 or - N THE ART SAW FILI G.

fo r - t t - f a rip saw for s raigh grained stu f. It will b e seen that each tooth is a small chisel , paring an dl eavin a regular shaving, ga groove behind w o f r b it the idth the chisel o tooth . shows the actual form and direction of the point and

‘ shaving. It is easy to imagine the ease with which such a saw would pas s through a board o f lengthwise . The whole being a succession sharp , would cut through a board with o f astonishing rapidity. The chips this saw

w . ill not be dust, but short shavings

82 Fig. .

2 h a . 3 , Fig , s ows the next best form of tooth “ - b an d or a hand rip saw . shows the true "

- THE ART or SAW FILING. 39 actual angle o f the point of the chisel that o f doe s the cutting . The pitch the tooth and the lin e of the p o in ts give the true angle of the cut n o t back o f , and the pitch and the the tooth , as would seem to be the case at first sight . We see a great difference between the cut

o f t b ting angle this ooth, shown at , and that

1 . at Fig . 3

This saw will work very well . The trouble is, the teeth are too slender at the points, and o r are apt to tremble chatter, especially if the h saw is crowded too ard . For straight- grained stuff this saw may be

filed square across, but as we are sure to come m ore or less in contact with cross - grain o r

is of a knots , it best to file the pitch the tooth t little beveling. For sof wood, after the saw n is set, hold the file at right a gles to the saw, and it will give a slight bevel to the points o f the teeth . For hard wood they should have a little m ore bevel still. 40 or - THE ART SAW FILING.

Fig. 38.

a . 33 an d et , Fig , shows the most common , y

of - saw b h s the worst form tooth for a rip . s ow

o f ab su r di the real cutting the tooth , and the ty of this shape . There is really no cutting about it . The wood is merely jammed o r scraped o u t with a very unnecessary exp en di ture of power . It seems strange that workmen will persist u of saw a in sing this kind , and yet, prob bly nine- tenths of the saws used are o f this fash io n ed tooth . — The Ver tica l M ll S a w. There are three different forms o f tooth used

- saw for the vertical mill saw. This must l e necessari y run perpendicularly, and therefor - THE ART or SAW FILING . 41 the action in contact with the grain of the

f - wood is di ferent from the hand saw . It is the same as the chisel in cutting down of the head a mortise .

Fig. 84.

a . 34 r of h , Fig , shows the correct fo m toot or - 42 THE ART SAW FILING . for a vertical mill - saw ; b is the shape o f the point o f the tooth set with the crotch - punch described hereafter ; 0 shows the actual shape o f o r action o f the cut the tooth . It is not enough that a saw cuts its chip or shaving. There must be space enough between the teeth to hold the shaving without crowd ing till it can be carried outside the stick and dropped . This reason alone sometimes causes a saw to run very badly, consequently large saws have ft o r a er a while to be gummed, more space made between the teeth . The saw- dust from this saw will be in square a m a blocks, like the chips from mortising chin e.

ART or - 44 THE SAW FILING.

s end of the wood . It is plain that thi shape o f tooth requires more power to cut its way l o n 4 . through the gthan that show at Fig. 3

Fig. 36. d a . 36 ol t , Fig , shows the , and still the mos ’ common shaped tooth for mill - saws ; b is t style o f setting o r bending the teeth ; 0 shows o f h the cutting angle the tooth . The s arp c r s n off al l a is o ner oo wears , and the s wing - 4 THE ART or AWFILING . 5 done by scraping and jamming with a great f waste o power.

- (fi r cu la r Rip S a ws .

The circular rip - saw has a still different

F i g. 87 .

in regard to the contact o f the teeth with the grain o f the wood . It will be seen by the figure that each tooth has a different bearing o n the grain o f the a wood as the saw revolves . shows the log and the direction o f the grain o r fibre of the b wood . It will be seen that the teeth at are o n cutting almost directly a line with the grain , while those at c are cutting almost at right

- angles, like the vertical mill saw . It requires much more power to cut with o r - 46 THE ART SAW FILING .

s these lower teeth than with the top ones . Thi is readily proved by sawing a plank with a.

aw R - large s . aise the saw table till the saw

an d just cuts through the top of the plank, perhaps the saw will run through it very easily ; while if you lower the table so that the plank will run as close to the centre o f t he saw as possible, it might be very likely to stop the saw, while it cut it at the top with ease . Almost every o n e who uses a slitting- saw

n ot of knows this fact, though perhaps aware o f f the philosophy the dif erence . It is merely the difference o f cutting o n a line with the

of n grain or across it, a stick to a lo g o r point cutting it square in two. We find three kinds of teeth in circular rip l saws, as well as the other kinds previous y de

. We o scribed should style them as g od, me diu m , and bad. - 4 THE ART or SAW FILING. 7

88 Fig. .

38 . . Fig. is the correct and proper form Fig

39 ll to o o n can s. wi do, but is light the points,

89 Fig. . in te gthe teeth to tremble o r chat r ; while Fig. 4 o r - 8 THE ART SAW FILING.

Fig. 40.

40 is the old scraper of which we have heard enough already . Almost any form o f too th can be drive n r through the wood by sheer force, but if powe of is any consequence, we shall study to adopt that kind which uses the least ; a circular- saw will last twice as long if made in the new way t of o l d ins ead the , because it will not get hot and thus warped and sprung o u t o f true so often . It is thought by good judges that the pitch of the tooth of a slitting - saw should n o t n f be less than a angle o sixty degrees . Perhaps it will be well to explai n here what n of is meant by an a gle sixty degrees .

Every circle, large or small , is divided into three hundred and sixty degrees ; a degree b e o r - 49 THE ART SAW FILING .

of e o f 360 ing the acuteness the angl s lines, radiating from the centre like the spokes o f w o f a heel , so that an angle sixty degrees is n the same o n a small circle as a large o e . The actual measurement of a degree o n the outside o f ff aff a circle is a di erent air. A degree on ’ the earth s surface is sixty - nine and a half

miles . 360 1 80 If a circle is , a half circle is , and a 90 quarter circle degrees . All we want for o u r purpose is a quarter circle.

iii 90

Fig. 41 .

Fig. 41 shows a half circle divided into o f angles ten degrees each . Co unting from d the horizontal , ninety degrees is perpen icular, o r n If a right a gle . we want to ascertain the 50 or - THE ART SAW FILING .

an gle of an y object from a certain line we call o n e n that line , and inety degrees from that is a

n right a gle . When the sun is half way u p to the meri

- five dian , we say it is forty degrees high ; when

t - a a quarter up , we say it is twen y two and

half degrees high , from the horizon .

To return to the saw, we want the pitch of the tooth an angle o f sixty degrees from the

n e u il at ~ horizontal . This a gle will form an q e

ral triangle, as will be seen by the figure . The same an gle is formed by describing a circle whose diameter is o n e half the diameter o f the saw, and drawing a line from the point o f s o f as the tooth , across the out ide the circle

“ M .

a w- ettin 7 S S g. "2 2 5 This is an important o f the work o f keeping a saw in order ; for a saw may be filed

very scientifically, and if badly set it will do its o r n o t work very poorly at all . The object o f setting is not to increase its

cutting power, for a saw will cut faster if not d set, provided it will pass through the woo

without pinching or binding.

2 o r S AW~ FI IN G 5 THE ART L .

d Many saws are being made latterly, groun thinner at the back , and we hope this practice will prevail ; for if a saw is ground thin at the back, and ground even and regular, and filed scientifically, it will need no setting. Many a is saw binds, not because it not set enough , but because it is filed so badly that it cuts ragged w and uneven , leaving the groove filled up ith

- o f the half severed fibres the wood, like sawing o f through a bale cotton . T he first consideration in setting is perfect u niformity . This is indispensable . The next i s the proper form of bending o r Opening the teeth .

o f - There are a great variety saw sets invented, m anufactured , sold, and used ; some are good ; a great proportion are good for nothing. Th e o l d way o f setting with a punch on a block o f

w is f . ood , very far rom the right way It is impossible to strike every blow alike, and the wood bein g the fulcrum over which the tooth

an d t he it s is bent, yields, tooth is bent clear to

saw. base, which is very likely to kink the

O n e - third of a tooth is all that should be set or f of turned out o line the blade. o - THE ART r SAW FILING . 53

A correct saw - set should be so constru cted mu st u that the tooth be bent just far eno gh,

can n ot and at the same time be bent too far, even O n of by repeated blows . a good piece steel on e f sometimes blow will have no ef ect, the tooth springing back again ; two o r three blows being necessary to make it stay where it should be . O n this account we think those sets that act o f n w like a pair plyers, bendi g the teeth ith the hand , quite objectionable, not being able to make the tooth stay set . o n e If or two teeth in a saw are bent too far, they only scratch and make the work rou gh and waste power ; while if n ot bent far enough they do nothing, and are drones in the hive . We believe the best saw - set to be found for ordinary sized teeth is that known as the “ " Fi . 43 Aiken set, represented by g . 54 ART or SA - THE WFILING.

48 Fig. .

Although this set was invented many years ago, it has never been superseded . Many spurious imitations of this set have been manufactured of poor material ; so it b e comes the buyer to be careful an d get the genu ine ; for if the material is not perfect, they are n worse than one at all . We believe the principle o f this set to be the correct one ; it is impossible to set the tooth too far. The steel is condensed , and the tooth is d o ut t n rawn , rather assis ing the file tha other

S ettin mil l an d other la r e saws as a t Fi s . g g , g

34 a nd 3 —L n o w 5 . arge and heavy saws are set - 55 THE ART or SAW FILING.

- h n a t with the crotch punc , which is represe ted

44 . Fig.

Fig. 44.

n of This pu ch is made steel , and very hard w in the fork, here it comes in contact with the of point the tooth . The teeth are not bent but S o u t o r 33 pread upset, as shown at Fig . . This is n o doubt the best way to set large it and heavy saws, being very difficult to bend G the teeth o f a thick saw regularly . reat care must be taken with this set to have the teeth 5 ART o r S A W- 6 THE FILING .

Spread even and regularly ; and they should be jointed o n both sides and tried with a o o n s t straight edge, and als the point , so tha every tooth shall be exactly in line with the o n e o u t others . If only tooth stands more than the others, it causes a waste of power and makes rough work besides .

o l d o f - The way setting mill saws, with an and hammer, is very bad . True, a saw will in this way by sheer force ; but if o n e - w set the right way, third less power ill

o n e - do the work, and consequently third more m a Speed y be obtained . n n In conclusio , we would say in selecti g as saws, in all other tools, always get the best, even at higher prices ; a good tool will always o ne give satisfaction to the buyer, while a poor is dear at any price .