Thread: Neat backsaw handle.

Originally Posted by IanW

Zero rake saws can be harder to start (particularly larger teeth), but it's their rougher action that puts me off. I'll accept that that's partly due to my less than perfect sharpening abilities, it only takes one or two slightly high tips to make a saw feel rough, but the more forward the rake, the more those small errors make themselves felt.

Cheers,

Ian

My own view is that sharpening abilities play little part compared to rake. As you have alluded, as the teeth become larger, the tendency towards zero rake becomes more obvious and smooth sawing becomes awkward at the least and painful at worst. If anybody doubts this they should try a 4ppi saw with zero rake. In times gone by this was partly alleviated with the progressive tooth. So a 5ppi saw started with 6ppi for a couple of inches and then 5½ppi for another couple before going to the nominated tooth count. A further refinement is to relax the rake over the same distance and I know of one saw sharpener who does this.

However, with the small teeth we are talking about all this is less noticeable and none of the foregoing is commonly seen on back saws. There is one exception which may have been Disston's No.77 "no set" (I will have to check this) ,which began with very fine teeth before going to 8ppi or 10ppi. As I think you have pointed out, at ppi of 15 and more there is not really any benefit in filing the teeth other than rip. I have found that cutting end grain (dovetails and lap joints) is more demanding than on the face of timber and any deficiencies manifest themselves more prominently.

I agree too that the majority of saws and tasks will be suited to rake angles between 5° and 7° for rip teeth.

I realise that we have lapsed into saw teeth instead of saw handles and must apologise to Planemaker for the digression. It seems we can't help ourselves.

Regards
Paul

Originally Posted by Bushmiller

....However, with the small teeth we are talking about all this is less noticeable and none of the foregoing is commonly seen on back saws. There is one exception which may have been Disston's No.77 "no set" (I will have to check this), which began with very fine teeth before going to 8ppi or 10ppi.

OK, I apologise to Stewie if this is hijacking, but we are talking handles & grip angles & effect on a saw's apparent aggressiveness so I think it's reasonable that tooth profiles have entered the discussion.

Paul, I think you will notice small changes in rake angles with small teeth, it was on a 15tpi saw that I first became aware that such small changes in rake had a noticable effect. However, I agree that it's even more noticeable with larger teeth.

There has been at least one "modern" backsaw offered with progressive pitch, but I've never heard of older backsaws having progressive pitch. Frankly, I think it's just a gimmick & quite unnecessary on a backsaw.

I've never seen a 77 handsaw, let alone used one, but have briefly had my hands on a 77 backsaw. It seems like both the rip & xcut versions of these were filed differently from "normal" saws The handsaws have 'extra' taper on their blades & the backsaws are also tapered. I can't find the thread where I described re-furbishing the 77 backsaw, but it was quite an education for me. I discovered that the saw simply wouldn't work without the 45 degree fleam. When it came into my hands it had been re-sharpened with a fleam angle more like 30 deg iirc, and on my first attempt to sharpen I simply followed what was there. The thing cut like a dog & bogged down about a half inch into a cut! In the entry for the 77 on the Disstonian site, it says "The teeth had no set, and the 45 degree bevel was meant to cut wood in a way that saw dust would fall easily from the teeth and keep the path clear for the blade to continue cutting".

Well, it certainly does something, after 'correcting' the fleam it was a different saw. Without set, it had zero steerability, so you had to start absolutely parallel to your cut line and use a light touch, but it would cut straight for the full depth of the blade. Not an aggressive cutter, but fast enough, and very smooth...

Cheers,

Paul & IanW; no need to apologise. Discussions on rake angle, hang angle, ppi/tpi, are all integral to saw making and sharpening.

cheers Stewie;

Originally Posted by planemaker

it may also be partly due to the zero rake angle.

The agressivness of a back saw is allways result of 4 factors:

Rake: the lower, the more aggressiv.
Weight of spine: the heavier the more agressive
handle position (part of that is the hang angel) the more downward pressure, the more agressive
Thicknes of blade: The thinner the more agressiv.

The same with backless saws, just without the back.

Cheers
Pedder

Pedder, I am reluctant to argue with someone who has a vastly higher profile in the saw world than I, but I question your assertion that "the thinner the plate, the more aggressive". Several years ago, I set out to confirm this bit of received wisdom, i.e., that all else being equal, the thinner the saw the quicker it cuts. I made three (rip) saws that were identical except for the plate thickness. I made multiple groups of the same number of strokes with each saw in different woods, changing the order in which I used the saws between each lot. I measured the the length of each cut & calculated the mean & standard deviation & did a t-test which showed no significant difference between saws. There was more variation in the length of the cuts each saw made for the same number of strokes than between them. Since I was trying to "prove" the opposite, I don't think I unconciously biased my sawing to favour the thicker saws, but you can never be sure when a human arm has to be the operating device & is controlled by a human brain. The quality of the data could be much improved if you had several people who did not know what we were trying to prove, with none of them knowing there was any difference between the saws.

On reflection, I decided the result I got is likely to be real, based on the following analysis. If the teeth are of equal pitch & rake angle, and subject to the same cutting pressure (given there was a difference of 0.010" between the thickest & thinnest plates, the difference in saw weight was tiny & unlikely to have any significant impact), each tooth should remove the same depth of wood as it traverses the cut regardless of its width. The only difference is that the thicker saw has to remove slightly wider chips. This will, of course, require a little more energy input per stroke, but the depth of cut for each stroke should be the same for all of the saws. With the smallish saws I used, I could not tell that the thicker saw was any harder to push, you'd need a more sensitive instrument than my arm to reliably measure that.

It is nearly impossible to remove subjectivity from any such comparison of tools - any tool we think is "better" even if we just like its appearance more, is liable to perform better in our hands than one we don't like, despite someone telling us it's more ergonomic or whatever. Viva la difference, but let's remain aware that our preferences are determined largely by subjective rather than objective criteria.

Cheers,

Originally Posted by IanW

Pedder, I am reluctant to argue with someone who has a vastly higher profile in the saw world than I, but I question your assertion that "the thinner the plate, the more aggressive".

Ian, i think we both make saw for 10years +x, so no need need to be reluctant. And please don't forget: I I want to have serious talk about saws, i can't use my mother tongue.

Originally Posted by IanW

The only difference is that the thicker saw has to remove slightly wider chips. This will, of course, require a little more energy input per stroke,

But that is what I would describe as agressivnes or speed.
Klaus and I made, now I make, the western saws with the thinnest blades.
0.3mm. I even make tiny 1saws with 0.2mm.
If you push them with the same energy you push a 0.5mm blade you will hurt yourself and the saw and the wood.
So you need less power to have the same depth of cut, I would say the saw is more aggressiv. Or faster, if you like that better.


The position of the handle and the weight of the spine are by fare more relevant.
They are the same thing: it is the proportion of forward energy to downward energy.

OK, I think we are approaching the same page. I can see the language barrier is not helping us, for sure. You seem to be using "aggressive" the way I'd use the word "bite" - both are a bit loose & vague which is causing us some misunderstanding. Let's define "aggressive" as the resistance of a saw to being pushed forward along the cut. This is quite different from what I mean by "speed of cut" which is how much the kerf deepens per stroke. A saw which is inappropriate for the task due to tooth pitch & form may offer more resistance to being pushed through the cut (i.e. it may feel more "aggesssive"), yet travel a shorter distance per stroke & use up more energy than a saw of the same size with a more appropriate tooth pitch & pattern, so I think the distinction is worth making.

There are several assumptions to be made in any comparison of saws & the biggest assumption is that the sawyer is using the saw in a way that gets optimum performance, i.e. the teeth are removing the maximum amount of wood consistent with clean cutting. This is a learnt skill, most beginners & even many moderately experienced sawyers I watch put far more pressure on the blade than they need (well, many are battling with dull saws, too!). If the saw is adequately sharp, excess pressure will cause the teeth to bite into the wood deeply, clogging the gullets and reducing efficiency. This is liable to lead to binding & erratic cutting (I'm sure you are well aware of this!). One of the reasons I labour this point is because at a very tender age, my father put me on the end of what appeared to my young eyes as a very large crosscut saw, & I cannot count the number of times he admonished me for "leaning on the saw", his term for applying too much pressure. I slowly got the hang of it & eventually developed a touch to match his with the result we'd saw through a log in half the time. Lessons learned at an early age tend to stick with us..

I absolutely agree that wider saws will take more energy to cut the same distance, it's axiomatic, you have to remove more wood to let the saw pass. But the difference is so small it would be hard to measure accurately. You could probably detect the difference with a couple of large handsaws of different plate thickness, but I somehow doubt you could do it reliably & consistently due to other confounding factors - the amount of taper on the blade or even its degree of polish can affect resistance at least as much as a very small increase in chip width. If I want a saw to cut quickly (i.e. move the maximum distance per stroke), I look to the tooth pitch & form rather than plate thickness because imo, over the range of typical plate thicknesses we use, it is a very minor factor in the equation.

Saws of 0.2mm plate are interesting! That's 8 thou (sorry, but for some reason I still can only think of some dimensions in Imperial units, so I have to convert mm to "thous" or thousandths of an inch to get a mental comparison of saw plate thicknesses). The thinnest saws I've made for other people were 15 thou, which is 0.38mm & significantly thicker, but the number of kinked & damaged old backsaws I've seen with even thicker plates (20 & 30 thou) does make me wonder what future some of these saws have if they fall into the wrong hands. Just for fun, I have made a few saws using 0.010" plate (not quite as fine as your 0.2mm!) but I fear they are a bit too delicate for all but the most careful users - they certainly don't come with a "lifetime guarantee".

Here's one compared with one of my "normal" D/T saws: 3.jpg

The blade is about 165mm long with a maximum blade exposure of about 25mm at the handle end & toothed at 24tpi (which is as fine as I can go with my ageing eyesight).

What sort of handles do you put on your little saws? I had difficulty with the little saws in keeping the handle in visual proportion, but of a size that can fit in a normal hand with sufficient comfort to make it usable. My hand is on the small end of medium, and this one only just fits: 4.jpg

I also tried a sort of knife handle, which is easy to hold, but it didn't feel as controllable as the pistol type above: Ultra thin 1.jpg

The 10 thou saws cut more slowly than my 15 thou D/T saws, due a little to the finer pitch, but mainly because they have a much shorter stroke (D/T saws have 225-230mm blades). They are suited for fine box making or model making but not practical tools for the average cabinet shop...

Cheers,
Ian

Originally Posted by planemaker

Derek; it may also be partly due to the zero rake angle.

regards Stewie;

Stewie, I checked the teeth yesterday, and they are a zero rake, which is far more vertical than I recalled. I agree that this makes for a hard-to-start saw. The combination with the high hang is unfortunate. I am tempted to alter one or the other, perhaps both.

Regards from Perth

Derek

Originally Posted by derekcohen

...... I am tempted to alter one or the other, perhaps both....

Derek, I would most definitely ease the rake back several degrees. Given the woods you typically use, I think you will find it makes a big difference both to ease of starting & the action of the saw and is unlikely to reduce the speed of cut significantly. You can admonish me if my predictions are wrong, but I'll take that chance....

Ian

Originally Posted by derekcohen

Stewie, I checked the teeth yesterday, and they are a zero rake, which is far more vertical than I recalled. I agree that this makes for a hard-to-start saw. The combination with the high hang is unfortunate. I am tempted to alter one or the other, perhaps both.

Regards from Perth

Derek

Hi Derek; appreciate the feedback. I wouldnt attempt making a change the hang angle. Youl'll end up having to elongate the holes on the saw plate to accomodate the change. Backing of the rake angle by 5* should make it a lot easier to start the saw. Good luck with the changes.

With regards; Stewie

Ian a tangent but if you ever sell off any of your saws again, price them for what they are worth, which I remember was much more than you asked for. Rob Cosman sells his for up to $300 USD.

Originally Posted by IanW

OK, I think we are approaching the same page. I can see the language barrier is not helping us, for sure. You seem to be using "aggressive" the way I'd use the word "bite" - both are a bit loose & vague which is causing us some misunderstanding. Let's define "aggressive" as the resistance of a saw to being pushed forward along the cut.

Hi Ian, I don't agree with your definition. But if that is the definition (As a lawer I am open for funny definitions), than I agree! Than a thicker blade is more agressive. (needs more joule to be pushed)

Originally Posted by IanW

Saws of 0.2mm plate are interesting! [...] What sort of handles do you put on your little saws?

They get a special gent's saw handle. More a kind of file handle


in the middle with fresh padauk handle

Theses saws are made to cut slim cuts. Best way to prepare a lambs tonge for carving, is to cut a tiny cerve.
The hole process:

Old Ladies: lammerzunge - lambs togue

Cheers
Pedder

1st batch of brass hardbacks have been cut to width, length, and stamped on the hydraulic press.

regards Stewie;

Cutting the slot on the router table to 0.020" for the dovetail saw hardbacks.

A big thanks to Paul (Bushmiller) for helping out with a replacement switch assembly on the Triton Router.

regards Stewie;