Taper Grinding Panel Saw Blades?

[Niels Cosman]

Hey all,
I was wondering what sort of techniques can be used to taper grind the saw plates of panel saws without sophisticated equipment. I seem to recall seeing someone using a hand belt sander somewhere in on the interwebs. I have been trolling and googling and can't seem to find any answers.

I was thinking about using an adjustable speed waterfed-angle grinder with Silcon Carbide pads I normally use for grinding glass. I also have access to large wet beltsanders and a 36" SiC flat lapping machine. I imagine that any technique that generates excessive heat is not desirable.

Cheers,
Niels

[george wilson]

You had better generate NO heat,or you risk badly bulging the heated surface permanently. In the 18th.C.,they probably just scrubbed the saw blade with hand stones more on one side than the other if they wanted to make a tapered blade.

[Niels Cosman]

Hi George,
Thanks for the warning- I was hoping you would chime in. For the saws you made at Williamsburg did you taper the blades, or was this feature more modern feature that was omitted?
Cheers,
Niels

[David Weaver]

Neils, scrape or sand, have a way to measure progress. I heard wenzloff was stoning off metal with a tormek at one time (yeah, figure that out).

With some reasonable touch, you might be able to make progressively shorter strokes closer to the top of the toe to taper a saw. I'd absolutely count them and make them the same, and I'd try it on a chubby $2 flea market saw first. Could be interesting for the rest of us if you try it.

Disston had some ungodly setup of huge stones that's not even worth discussing for home users.

[Niels Cosman]

I'd try it on a chubby $2 flea market saw first. Could be interesting for the rest of us if you try it.

Hi David,
Sounds like a great idea, I have just the chubby saw for the task!
Cheers,
Niels

[george wilson]

A chubby saw sounds painful.

[Jim Paulson]

Guys,
I think you have scared me off from attempting to taper grind a saw blade. Truth be told I wasn't inclined to even try it.
But I appreciate the thread as great information. Again thanks George for providing some input here.

Take care,
Jim

[george wilson]

He could have been using the side of a Tormek's wheel to grind off blades. I can see that,though I wonder how long the side of the wheel lasted until it had to be dressed back flat.

I had planned to use a large cup wheel running on a track,with the blade laid below,before Jay Gaynor told me that he didn't think 18th.C. blades were tapered,or not tapered enough to worry about. I would have flooded the wheel and blade with coolant,just water,probably.

[Harlan Barnhart]

One of these days I'm gonna try to do this. I'll probably lay the saw on a flat surface use a belt sander, count the strokes, flip it over and do the same. If you go slow and monitor the progress with calipers, I think it should work. Of course I'll start with a saw I don't care much about.

[Niels Cosman]

Im going to give it a go on a junk pile saw this weekend with my alpha grinder working slowly and checking the work as I go. If grinder has no problem heating up glass then im confident I can make it work for steel. I'll report back the results.
ps. the pads on the left half are SiC the pads on the right half are diamond.
184830184831

[David Kuzdrall]

How did this turn out?

[Christian Castillo]

I know Japanese saw makers taper their saw plates by hand using a scraper called a sen. You can google more information on the scraper, as for how well it works, the Japanese make remarkable saws... but then they have years of practice with the sen tool.

[Chris Vandiver]

Some Japanese chisel and plane iron makers still use a sen to create the back hollow(ura)on their blades. I would think that Stuart(Tools From Japan) would be able to find any variety of sens, for anyone interested. They would probably work just fine on western saws, which are a bit softer than handmade Japanese saws. I'll bet a sen would work great for a backsaw, if one wanted to taper it like a Disston #77 no set saw.

[David Kuzdrall]

Some Japanese chisel and plane iron makers still use a sen to create the back hollow(ura)on their blades. I would think that Stuart(Tools From Japan) would be able to find any variety of sens, for anyone interested. They would probably work just fine on western saws, which are a bit softer than handmade Japanese saws. I'll bet a sen would work great for a backsaw, if one wanted to taper it like a Disston #77 no set saw.

Which Stuart? Thx

[Isaac Smith]

Some Japanese chisel and plane iron makers still use a sen to create the back hollow(ura)on their blades. I would think that Stuart(Tools From Japan) would be able to find any variety of sens, for anyone interested. They would probably work just fine on western saws, which are a bit softer than handmade Japanese saws. I'll bet a sen would work great for a backsaw, if one wanted to taper it like a Disston #77 no set saw.

I'd be really interested in seeing this done. Do you have any idea how long it takes them to scrape a blade? How much taper do they put into them, and what are the sizes of the blades they do this to? I am woefully ignorant on the subject of Japanese saws.

I made a patternmaker's saw a few years back. The blade is 0.032" thick spring steel, about 9" long and 1 1/2" deep. The originals I have seen all had tapered blades, so I decided to do the same. I tried it on a belt grinder, which did not work at all for me. I ended up scraping the blade with an old mill file whose tip I ground and sharpened. It worked very well, but took a couple of hours, if my memory is correct. Plus a fair amount of time sanding it afterwards. The blade tapers from 0.032" at the teeth to 0.025" at the back. It also tapers in thickness from the heel to the toe, although to a lesser extent.

I can't imagine tapering something the size of a panel saw, though. Not without feeling sore, that is.

http://www.blackburntools.com/woodnet-pictures/patternmakers-saw/pm-saw-4.jpg


http://www.blackburntools.com/woodnet-pictures/patternmakers-saw/pm-saw-6.jpg

[Chris Vandiver]

Which Stuart? Thx

It's Stuart Tierney at Tools From Japan

[Chris Vandiver]

Hey Issac,

Love the pattern maker's saw. Very tastefully executed. A real beauty!

All manner of handmade Japanese saws are hand scraped. From very small to quite large they are at least scraped for uniform thickness if not for taper. Ryoba saws(teeth on either side of the blade) are scraped for taper down the middle section of the blade. Handmade japanese saws are forged from carbon steel(white steel #2 mostly) and when they come out of the heat treatment, the blades look like a potato chip. They are then straighted and stretched with a hammer until perfectly straight and flat which puts a lot of tension in the blade. I just checked the taper on a standard quality handmade 210mm ryoba saw(this is a relatively small saw) and the taper was .0165 at the gullet line to .0130 at the center of the blade. This saw has very little set and it never binds in the cut. In fact it runs very smoothly both rip and x-cut.

There is a Japanese saw expert that lives in Vermont. His name is Mark Grable. He studied for awhile with a renown sawmaker in Japan. If your interested I can put you in contact with him. Just PM me and I'll send you his contact info.

[Jim Matthews]

What's the clearance sought between the tooth line and the "top" of the plate?

Aren't we talking about less than a thousandth of an inch?
It seems to me that should be manageable with a lapping plate.

Unless I'm dealing with a saw that has no set, what's the advantage of doing this?

[Steve Friedman]

I'd be really interested in seeing this done. Do you have any idea how long it takes them to scrape a blade? How much taper do they put into them, and what are the sizes of the blades they do this to? I am woefully ignorant on the subject of Japanese saws.

I made a patternmaker's saw a few years back. The blade is 0.032" thick spring steel, about 9" long and 1 1/2" deep. The originals I have seen all had tapered blades, so I decided to do the same. I tried it on a belt grinder, which did not work at all for me. I ended up scraping the blade with an old mill file whose tip I ground and sharpened. It worked very well, but took a couple of hours, if my memory is correct. Plus a fair amount of time sanding it afterwards. The blade tapers from 0.032" at the teeth to 0.025" at the back. It also tapers in thickness from the heel to the toe, although to a lesser extent.

I can't imagine tapering something the size of a panel saw, though. Not without feeling sore, that is.

http://www.blackburntools.com/woodnet-pictures/patternmakers-saw/pm-saw-4.jpg


http://www.blackburntools.com/woodnet-pictures/patternmakers-saw/pm-saw-6.jpg

Isaac,

Nice to see you posting on SMC. Does that mean you're not going to start making full sized hand saws in the near future? Given your incredible saw making skills and you knack for mechanical innovation, if anyone can figure out a way to make tapering saw blades commercially feasible, I would have thought it would be you.

Steve

Steve