Thread: Saw thickness and taper

The thing is ... my very limited concept of what a saw is ... was/is a pretty stiff piece of metal sheet, and the $10 D8 that got me started on all this saw stuff really backed up that picture.

Giving *it* the bend test, it barely deigned to flex at all. And I found that I had several non-champagne saws that fitted that same behaviour ... all exhibiting about the same reluctance to circle the wagons ... including a modern Irwin hardpoint that cuts like a demon.

On top of this, I have had for sometime a very rough 26" Disston handsaw 3.5tpi that on test cutting, and flexing in my hands, I figured had maybe been in a fire or something because it was so different to my picture of what a saw should be. I basically figured that it was unusable, particularly with that coarse tooth pitch.

Paul.

Edited - I had the wrong (rough) saw

As a result, I decided to make some measurements on the blade width of the #9. And realising that I now had 4 (in fact I think it is 7) visually similar saws that are quite different to each other, I want to measure them ... and then try to find out ... What's the Deal???

(Off to work now )

Cheers,
Paul.

Just a quick one Not so much as it turned out ...

Measuring out a tapered sawblade is not the simplest matter ... see the illustration I pinched from RayG.

With the #9 I bought I started off by measuring the width along the back and along the toothline.

The result (toe to the left, heel to the right, back uppermost) was
T 20 24 27 30 H back
. 27 31 32 32 . edge
(measured in thou's of an inch at roughly equal intervals)

Put the results together from another 4 or more saws and it starts looking like an ugly pile of numbers.

I want to roughly and simply characterise each saw. At first I thought of just estimating the width of the sawblade at the rough centre of the saw blade , by averaging the width halfway at the edge and the back, but then I thought it would be better expressed as the width at the edge plus the taper to the back.
So the #9 becomes: edge .031" + taper .006" (halfway along the toothline)

I was searching and searching online and back through this forum and ... you dig and you dig and sometimes ... you find gold.

Don't get me wrong ... it has been a rain of fantastic information since I first opened my ever-flapping gob on the handsaw, but here is some 'Old Gold' ... bloody Bob Smalser again ... the only info I have yet found about widths and tapers online.

https://www.woodworkforums.com/f152/h...tml#post255341

He expresses it differently as the taper along the back, and the taper at the heel, and the taper along the edge.

In any case I need to go back and read it properly - and I haven't looked yet in all the 1900s 'Treatise on Saws and Filing' etc that I have downloaded.

What I'd like to get a handle on - hopefully maybe from Chippy for example - is an understanding of what blade width is useful for what - what teeth can it reasonably support - how the hell do you use a flippy little big blade that you can curve around into a circle - etc.

Cya.
Paul.

i would caution against bending all your saws around in a circle, yes they can do it, all to varying degrees but if you arnt familiar with them or quite know what your doing then use a bit of caution, you dont want to take it too far and damage them, newer saws (when i say newer i mean anything made in your lifetime and then some) are quite easy to take too far and put a bend in it, do it on a saw in the shop to test it LOL, but use a little restraint on your own saw shouldn't really bend too much on a store saw really either (was a bit tongue in cheek), just enough to give you the feel, with the handle still attached its not ideal to bend too severely, also many modern saws are hardened at the tooth line which gives the saw a different character across its blade, bending it too severely on purpose is being a little reckless with your tools

having said that, yeah a good ol saw will have plenty of spring, so will a new one but the old ones are often better for various reasons...its the tension in the blade that gives it that spring so its not that it can bend so much as its ability to spring back thats important, when your sawing you dont aim to cut crooked and not follow through the cut, straight, with your arm, elbow and shoulder behind the line of the saw do you? so the spring isnt there so you can cut with the saw crooked and purposely bend the blade as you cut. if the tension and spring wasnt there then the blade would fold up as you cut like a concertina , as an exaggerated example imagine a saw made from thin sheet lead, it would instantly fold up eh!, if it was thin sheet steel that wasn't tensioned and sprung it would do the same, if it was very thick sheet steel it wouldn't fold up but the blade (and teeth) would be too wide to push through the timber and cut by hand, so having tension allows the blade to made thinner to be useful for hand saws (band saw etc as well when it comes to that)

it is possible to have too 'flippy' a saw, they can feel too fast or loose, but its not something you will likely need to worry about, generally that is sorted out long before it gets to your hands by the saw maker, possibly an old saw thats been tampered with might have a problem but chances are you will notice when you first pick it up to handle and test...think i mentioned to you before in the other thread but you pick up an old saw and first see how you like the handle fit, if you dont like dont proceed further, then feel how it hangs, it should feel balanced and fall at the correct angle to meet the timber with the teeth where you want, you can sight the blade for straight and give it a flip from side to side to feel the blade and how even it is, give it a bend each way to feel how it springs back, then sight it again to see if any bends have shown up (or disappeared), bending it can relax a point that was a little kinked before or show where it was kinked..oh and always try to play a tune on it see how it sings!

---
ground taper i think i mentioned early on in the other thread, thats one of things that makes the old saws better, new saws generally (if none at all) arnt taper ground, i think you are probably getting it now, i am sure with all those links you have found that it has been mentioned already but the taper grind of the saw benefits in a few ways, it allows the saw to cut through the timber without binding, allows a smaller set on the teeth to be used which obviously means the kerf is smaller which means you arnt having to push through as much timber as you cut, it also makes the saw lighter and makes the centre of gravity (for lack of a better phrase) down to the tooth line, makes the saw feel more balanced to me, its extra work and more involved than just grinding or perhaps it would be done nowadays, after grinding in the old days they did other steps to the blade like tensioning and such even though lots of work was done before grinding, so its not just a case of grinding a saw plate. also even on some of the old saws some might be ground in say three different steps whereas a more expensive saw plate might be ground in 5 steps, both work well and you should be grateful for the work compared to a new saw

thickness of the saw plate is a matter of metallurgy, hardness and tempering and such and what the saw is designed to do, and these things changed through the different centuries and decades so its not quite like comparing apples to apples, all things being equal better quality steel can be thinner to do the same job, things that might effect the choice are what forces are going to be placed on the teeth (hardwood or softwood how much bevel, set or whether no set at all e.g. acme 120, believe it or not even some old backsaws were made to be used with no set, they were taper ground but a bit different to a hand saw). generally though the thicker the plate the bigger the teeth it can support

$250 and upwards for london spring steel! gward! well thats probably due to threads like this all over the world and people going over the top, dont pay that much!!! the Disston company were nothing if not good at marketing but its just a marketing term, you would find not a lot of difference in other saw blades of the same comparable years (more so with later years, 1920 onwards for example, around turn of the century or before differences are prob greater), even among the disston line (within reason), sometimes it was extra work that made one saw better (more expensive) than another, some were highly polished, others not, but otherwise they are the same saw plate, both work well and chances are the polish on some has ,umm, kinda disappeared now anyway

btw, which saw are you calling a number 9 (#9) , i cant see it, not the bottom one on that group pic of four is it? that a D-8 (single grip) the other is a D-8 duel grip (w/thumbhole)...edit; i see now, the pic is higher up, looks like #9, with a skew back

the D-8 with just 3 1/2 teeth can sound decidedly dead and not curve/spring at all like a 5 1/2 tooth D-8, i dont know but i sometimes think they are made out of different stuff (maybe they are early saws) but they still cut like a demon (to pinch your phrase) if sharpened up, they can be quite deadly!, they are often thicker steel though so it has to feel different, i doubt many folk would have much use for them nowadays, they are more for cutting/ripping beams and thicker timber and i think most people would go to the power saw instead nowadays, 5 1/2 ppi and more are still quite useful though and easy to use...your modern Irwins and such probably have hardened teeth, they can cut like a demon, and if you dont use them all day every day they would probably last for years before needing resharpening, heck i reckon i have some old sandvik's, short sleek looking, slight skew back, shark nose point, panel saws here i used to buy quite often, many are worn and some have been retoothed but one in particular thats always been a bit modelcodled but used intermittently for decades still has some life in it yet, they arnt quite like using an old saw, lots of things about them isnt as good ( i think they use too much chromium in them sometimes too, makes them gummy /sticky to resharpen once you have gotten rid of the hardened steel tooth) but they do have some advantages, teeth that last for yonks and the blades dont bend under their own weight when you hold them at angles above your head, which is kinda handy for crawling around roofs and tight spaces, and cutting something overhead at a weird angle with your eyes closed, they cut PVC pipe too LOL

cheers
chippy

I was pleased to be able to gather some more data here:
Building the Super Sawbench, p. II - Roughing Sawbench Parts by Matthew Cianci

A Disston #7 : .032" at the toothline with an .008" taper , although that is not necessarily measured at the halfway point.

Back to my original 4 D8-type saws ... plus three more.

I've written the measurements + how flexible they were.

A: width .037" - taper .003". medium.
B: width .043" - taper .008". stiff.
C: width .036" - taper .005". flexible.
D: width .035" - taper .008". flexible.

(the rest haven't been pictured)
E: width .041" - taper .005". medium. [S&J Spearior 888]
F: width .044" - taper .002". stiff. [D8 1940s+]
G: width .035" - taper .004". flexible. [D8 1940s+]

Compare that to the sawbench guy ... his #7 is .032" so should be quite whippy, I'm thinking.

I've translated Bob Smalser's measurements and come up with ... (all Disston) ...
#7 : width .041" - taper .007" and described by him as "an exceptionally tough and stiff saw"
#16: width .032" - taper .006"
#12: width .034" - taper .008"

He goes on to say "What makes them cut easier than the #7, however, isn't the taper, as the #7 has even greater taper...it's significantly thinner blades that average around .0345 instead of .0413".

His stated averages agree with my calculated guesses, but I'm not sure he's right about the "greater taper".
The #7 is about the same vertical taper (7 thou) from toe to heel.
The vertical taper of the #16 is 9 thou at the toe to 3 at the heel.
The vertical taper of the #12 is 13 thou at the toe to 3 at the heel.

So ... I'm guessing the width of the blade at the toothline is a major factor in ease of cut, and taper ... maybe less so.

For one thing it is surprising (to me) the difference between a 45 thou width and a 35 thou width on the flexibility ... although I guess it is 30% more metal.

Also I guess I can accept the blade of my #9 as being what you should expect ... .032" toothline, vertical taper from 7 down to 2 thou, and 20 thou at the upper edge of the toe. (I calculate BS's #16 and #12 as 19 thou at the upper edge of the toe)

Paul.

Hi Paul,

One thing that comes to mind when looking at how saws are smithed (tensioned if you prefer) is that they make a different sounds, a well smithed hand saw has a particular sound, sort of clean "sawing" sound that's easy to recognize hard to describe...

In comparing those saws, try each one on the same timber and see how the sound compares...

Regards
Ray

Ok - well while all this may have confused - and bored - the hell out of anyone else ... I think I have learnt something ... and I like it when I can get an overall perspective on something ...

How thick is a handsaw blade?
Where does it taper, and how much?
What numbers make it flexible or stiff?

A couple more little tidbits.

The Irwin hard-point is an untapered 41 thou.

The medium two-man saw I have is 65 thou with 8 thou taper - at the mid-point ... but is pretty damn flexible.

One very much puzzles me. 26" Disston somethin-or-other. It tapers from 25-33 thou along the back, 26-36 thou along the front - and is very flexible.
But the teeth are 3.5tpi.
This is the one I thought of as unworkable.
Am I wrong? Does this arrangement make any sense?

Thanks very much for the reply Chippy. I can see myself using one of the stiff saws ... almost a no-brainer. What about the more flexible ones? Are they for specific purposes? Do they need to be used more carefully? Does it make sense to have a thin-bladed 4 or 5 tpi rip saw?

Thanks,
Paul.

The thickness and taper of a blade are only a small part of the equation, when determining "stiffness. The smithing of the blade, or tensioning, is what makes a saw fast or loose. You can make a thick blade loose and "whippy", and you can make a thin blade "stiff", and it will ring like a bell. A good quality spring steel blade can be bent around in a circle, and it will return to straight on it's own, if its been properly smithed. If the blade doesn't have a clear ring to it and you bend it, it will bend and retain some of the bend. Very old saws, or saws that have been resmithed, to repair a kink or other damage, probably shouldn't be tested in this way, for they could crack.

Toby

Originally Posted by RayG

Hi Paul,

One thing that comes to mind when looking at how saws are smithed (tensioned if you prefer) is that they make a different sounds, a well smithed hand saw has a particular sound, sort of clean "sawing" sound that's easy to recognize hard to describe...

In comparing those saws, try each one on the same timber and see how the sound compares...

Regards
Ray

I will certainly move on to sharpening and testing these saws now.
Thanks Ray,
Paul.

Coupla pics ...

From Simmonds 1916 How to File a Handsaw

and from Brent Beach ... a pic I would never have come across.

Originally Posted by pmcgee

...One very much puzzles me. 26" Disston somethin-or-other. It tapers from 25-33 thou along the back, 26-36 thou along the front - and is very flexible.
But the teeth are 3.5tpi.
This is the one I thought of as unworkable.
Am I wrong? Does this arrangement make any sense?......

From the pic I think the explanation is simply that this old girl has been sharpened to near-oblivion. The thickness of the saw plate should be pretty much the same all along the tooth line - it makes no sense to have it otherwise. Whoever owned this saw touched up the toe end more often & more heavily, with the result the toe has come down much more than the heel (it may have been breasted, too, but the tooth line looks pretty straight now).

Anyway, the result is that the toe end has shifted more into the taper compared with the heel, which has moved less (and also the taper is more gradual toward the heel as shown in the diagram you posted).

This saw is probably a candidate for painting & hanging over your bar (), because it's now a bit too thin for comfort (if it catches on a heavy stroke, it could kink badly). But maybe it could still be useful as a finer-toothed saw. What the old blokes of my dad's generation often did was to cut them down to 18-20" for a 'panel' saw. I've got one I picked up for a couple of $$s at a flea market, and a right useful little thing it is at times....

Cheers,

Originally Posted by IanW

From the pic I think the explanation is simply that this old girl has been sharpened to near-oblivion. The thickness of the saw plate should be pretty much the same all along the tooth line - it makes no sense to have it otherwise.

Yes, of course - thanks IanW - I should have picked up on that after all that posting!


Video - Daryl Weir with an ACME 120
woodnet :: DSCN3758.mp4 video by daryl_weir - Photobucket

and Wooo-hooo check out the saw vice ...
http://s279.photobucket.com/albums/k...3DDSC08565.jpg

Those Acme saw vices are really something. Here's a few more...

lh4.googleusercontent.com/-TQodwu5FQBM/SYMavsUaKEI/AAAAAAAADa0/arZuhedZG40/IMG_0196.JPG

lh5.googleusercontent.com/-0Gd15nuy79w/Tjvhuml_r1I/AAAAAAAAAEs/3mxjYGFifXM/s1280/110804%252520restored%

http://i250.photobucket.com/albums/g...t/DSC_3210.jpg

They are part of a saw filing machine like this...

http://3.bp.blogspot.com/_z4ZtNOMO56.../s400/acme.JPG

Here is a better picture. http://badaxetoolworks.com/images/ch...-saw-filer.jpg