Thread: Anorexia saws

Originally Posted by Colin62

I can't agree with that. The reduction in sawdust generated is offset by the fact that the gullets also get narrower along with the blade, and if you're taking the same depth with each stroke, your gullet will need to be the same size (same depth).

Colin, I did the geometry/trigonometry in my head & got confused. There's less swarf, & the same section area (gullet), but I forgot the space is narrower, which I guess reduces the volume proportionately. Should've drawn myself a diagram!

Someone said that the thinner plate is easier to sharpen; less metal to remove and so the files will last longer. Not true, in my experience. The thin plate seems to be tougher on files, possibly because it catches on the teeth of the file more. It may be the hardness of the plate, but I've noticed this effect over several batches of plate. Again, it's relatively minor, and not a game-stopper.

So we're left with thinner saws requiring less effort (all things being equal, as Derek points out), and my observation is that the difference between say 15 & 20 thou plate is too small to be of concern, given that such saws are only used for shallow cuts & for a few minutes at a time. So as long as the plate thickness is appropriate to the length/width of the saw blade, the main effect of 'thick' or 'thin' is on perception. Which is an important effect - if you are happy with the way a tool feels in your hand, you are likely to do a better job with it....

Cheers,

For the sake of my answer, and I feel like for this argument in general, you should assume the same pitch and rake, with the saw plate being the only variable.

It's a matter of the effort required to push the saw through the wood. Thinner plate means less contact at any given time with the same amount of new cut created. One stroke on a 15tpi saw at 0.025" or 0.015" advances the cut the same amount, but the thinner plate is easier to push through the wood, same as a number 3 plane is easier to push than a 7. Easier to push means less large muscle engagement, less large muscle engagement means more control. At least that has been my experience.

Sharpening could be debated either way. I find it easier to oversharpen my thinner plate saws, so it requires a lighter touch. To say one is easier or harder is semantics, because, as usual, it depends on which factors you consider.

Cheers,
Luke

Originally Posted by ian

.......so, perhaps, the modern use of much thinner plate for high tpi saws is related in some way to the difficulty of applying set to small teeth cut into thick plate.......

Very true, I'd forgotten that point. I discovered very early in my saw-making that fine teeth & thick plate are not a happy marriage. You can put small teeth on thick plate, but it is much harder to set them consistently, using the pliers type sets, & the results are pretty ordinary (at least that was my experience). I'm talking putting more than 12 tpi on say, 30 thou plate, but if you're looking at 15 vs 20 thou plate, and 15tpi, the difference is insignificant.

Originally Posted by ian

....... and perhaps the real "advantage" of hammer setting is that it can be achieved with thicker plate.....

Never having hammer-set small teeth, I can't vouch for that, but intuition tells me it might be so. A sharp hit from a hammer should move the metal you are wanting to move, while inertia keeps the rest of the plate still. However, it wouldn't be the first time my intuition has been wild of the mark, & I still reckon the main advantage of hammer setting is speed - in the right hands, of course, I don't think the results would be very pretty if I tried hammer-setting a 15tpi saw!......

Cheers,

Originally Posted by IanW

Very true, I'd forgotten that point. I discovered very early in my saw-making that fine teeth & thick plate are not a happy marriage. You can put small teeth on thick plate, but it is much harder to set them consistently, using the pliers type sets, & the results are pretty ordinary (at least that was my experience). I'm talking putting more than 12 tpi on say, 30 thou plate, but if you're looking at 15 vs 20 thou plate, and 15tpi, the difference is insignificant.

I did 15 ppi toothing on this saw (Anatomy, Functional Analysis and Reproduction of the Disston Joiners Saw) @ #9 using 0.042" steel. The small teeth required more effort to set than the teeth on a thinner plate of course but still doable. Lubricating the bearing points of the saw set makes the job easier and much more consistent.

Never having hammer-set small teeth, I can't vouch for that, but intuition tells me it might be so. A sharp hit from a hammer should move the metal you are wanting to move, while inertia keeps the rest of the plate still. However, it wouldn't be the first time my intuition has been wild of the mark, & I still reckon the main advantage of hammer setting is speed - in the right hands, of course, I don't think the results would be very pretty if I tried hammer-setting a 15tpi saw!......

Cheers,

In this thread (Handsaw setting methods: Hammer vs. Pliers) I examined the differences between hammer and pliers set saws. The maker of the hammer set saw I looked at is very adamant that hammer setting is superior but his result, if the saw I have is typical, is not. The most consistent set I've measured is on a post-WW2 NIB Disston D-95, see the table in the last post of the linked thread.

I don't doubt that hammer-setting can be done well, I just haven't encountered an example of such.

Originally Posted by rob streeper

W= k_t X [Potatoes/(kerf width X kerf depth X kerf length)] where k_t is the 'wood factor' of the timber.

Coffee just went out my nose....

Originally Posted by rob streeper

I did 15 ppi toothing on this saw (Anatomy, Functional Analysis and Reproduction of the Disston Joiners Saw) @ #9 using 0.042" steel. The small teeth required more effort to set than the teeth on a thinner plate of course but still doable. Lubricating the bearing points of the saw set makes the job easier and much more consistent.....

As I said, do-able but rarely necessary, eh Rob? In my case it was early in my saw-making and I was scrabbling for suitable material to work with. The saw in question was quickly consigned to the 'scraper material' pile, because the thick plate not only made clunky teeth, it made the whole saw clumsy & nose-heavy. I made a few lemons when starting out, but fortunately, I'm a quick learner, I only make the same mistake 3 or 4 times, as a rule....

Haven't thought of lubricating the contact points, but now you mention it, it seems like a darn good idea. I'm thinking a thin smear of oil along the tooth-line before you begin might do the trick? It should help the tool slide along to the next position as well as easing the slide of the tooth against the plunger as it moves over...

Originally Posted by rob streeper

......I don't doubt that hammer-setting can be done well, I just haven't encountered an example of such.....

Like I said, "in the right hands..".
I've only used one hammer-set saw that I'm aware of (& didn't know it was hammer-set at the time). It was a perfectly good saw, but there was nothing special about it. I thought it was slightly dull & would have benefited from a light touch-up, but that was about it.

I reckon it would take far more time than I am prepared to devote, to achieve the hand-eye co-ordination you'd need to get a consistent set, particularly on smaller teeth. Even pliers-setting gets a lot better with practice (at least it did for me!). You develop a steady rhythm & consistent placing of the plunger & it gives a noticeably better result. If you want to become a full-time saw-doc, perhaps hammer-setting would be a skill worth acquiring, but for anyone who just wants to sharpen their own saws, I think you'll do much better sticking with pliers! If things don't go quite to plan, stoning can at least make your saw cut in a straight line......

Cheers,

Ian, Not the saw blade, lube the contact points inside the saw set. The Zamak (Eclipse/Somax type) saw sets seem to benefit from lithium grease.

As to hammer setting, the self-proclaimed expert that made the saw I looked at in the thread I linked above didn't do any better than I did with an Aiken style set.

The D95 I mentioned looks like it was hammer set as it has very nice and uniform flats on the 'pushed face' of each tooth, quite unlike the appearance of the pushed faces of pliers set teeth. Unfortunately I haven't found any information as to how the Disston saws were set.

Originally Posted by rob streeper

Ian, Not the saw blade, lube the contact points inside the saw set. The Zamak (Eclipse/Somax type) saw sets seem to benefit from lithium grease.....

OK, Rob - I misunderstood. As it is, I keep the plunger mechanism well-lubricated, which does, as you say, make a big difference to smooth operation. However, the thought of lubricating the saw metal as well has taken root in my mind, & I'm going to give it a go at some time. It may help to minimise the marking of the teeth you mentioned, & it might diminish the scratches under the tooth-line where the primary plunger of my Eclipse type sets grip the plate. A very easy thing to do, & worth a try, at any rate.....

Cheers,

Hmm, I've never had my Somax sets mark a saw as the 42X's do if not cleaned up. I tried setting a few lubed blades, simply because I neglected to wipe the blade clean, and found that my sets tended to slip off of the teeth. I have a few Disston Triumph sets but haven't had time to work much with them, interesting (to me) that nobody talks about them on-line.

The 95 was possibly done by machine, it's very uniform, more so than any of the modern boutique saw makers products in my collection. I've been meaning to try my Bemaco but it's been sitting neglected for some time as I've got too much on my plate at the moment.

Originally Posted by rob streeper

....Hmm, I've never had my Somax sets mark a saw as the 42X's do if not cleaned up....

Well this is what my Somax does: Set marks.jpg

Compare that with a no-set saw: No set saw.jpg

The marks are extremely shallow - you can barely see them looking straight on, I had to use very oblique lighting to get them to show in the photo. They are insignificant in the extreme as far as function goes, just a little annoying that they are there at all, on a brand-new saw!

I've got a Somax & two Eclipses, the Somax is the blue model (for finer teeth), all leave little marks. I've checked the plungers numerous times, they seem to be perfectly flat. They probably pick up a few very fine filings that I don't notice - they get everywhere on the bench during a heavy saw-sharpening session, as I subsequently discover when I put a tool that's a bit magnetised anywhere near where I was working (even after I think I've swept the surface well!).....

Hmmmm. I have a Somax and a 42X and I have to say I have never noticed those marks on the plate. However I have just been considering getting my eyes checked . I am just about to set another saw so I will pay particular attention to this aspect.

Regards
Paul

Ian,

Wow, that's bad. My Somax sets have never produced that kind of marking. I have two 42X's, out of the box one of them put two pin-prick marks on the plates at every tooth, the other didn't. I removed the marks from the saw using a yellow Diapad and dressed the face of the plunger of the set to stop the problem recurring.

Regards,
Rob

Originally Posted by rob streeper

.......Wow, that's bad. My Somax sets have never produced that kind of marking.....

It's not really as bad as it looks in the picture, Rob. That saw was the most obvious I could find & I've used the lighting to make it stand out as much as possible. In fact, the same lighting shows all sorts of faint scratches on the toe end of the un-set saw, which I wasn't even aware of. You don't see them at all if you just hold the saw up in 'normal' diffuse light...

The scratches aren't hard to remove if I really want to, they disappear with a pass or two of 400 W&D. I'd just accepted they were part of the process, but if no-one else gets them, I should make a proper effort to eliminate them altogether! Next time I set a saw I'll take great care to make sure the contact surface is squeaky-clean before I start....

Cheers,