Dovetail (rip) tpi - suggestions?

ivan · 26 May 2008

Some time ago I followed Bob Wearing's advice and recut a small tennon saw to 10 tpi rip for cutting tennon cheeks. More lately an Adria small tennon came my way, which is 15tpi rip, very nice, but a bit coarse for d/t in lighter work? (The Adria d/t saw is also 15 point rip). To what rip tpi should I recut an old d/t saw*, intended for thinner stuff? I don't want to waste steel by too much trial and error, so hints gratefully rec'd!!

* currently a blunt ~ 22 tpi overset x cut shape, filed 90 deg. (ie. straight across)

Harbo · 26 May 2008

If you are wanting a very fine cut and your saw is already 22TPI then I would stick to that. Rip is filed straight across (at right angles).
I do not envy the task at that TPI though!

My Wenzloff D/T with 15 TPI works fine. Though I also have a Crown one with 24TPI.

Rpd

bugbear · 27 May 2008

ivan":10qzqd0y said:
More lately an Adria small tennon came my way, which is 15tpi rip, very nice, but a bit coarse for d/t in lighter work?

Since rake and fleam are important factors (in addition to TPI), I'd try a couple of practice DT's with the Adria, to see how you go.

Since ease of cutting and starting are very personal, other peoples' advice may be suspect.

BugBear

ivan · 27 May 2008

The 15 tpi Adria seems a bit brutal on stuff under 10mm; it appears filed at somewhere around 10 deg, with no fleam. I've added about 10 deg of fleam at the toe which seems to make starting easier.

I was hoping when recutting the x cut 'peg' teeth of the worn but newly aquired d/t saw to a rip pattern, that I could get down to say 18tpi*, as I find the common manufacturers' usual tiny (20+tpi) teeth very hard to set! 15 to 18, enough of a change?

* convenient hacksaw blade template available, too

Anonymous · 28 May 2008

A rule of thumb is to have 6-8 teeth in the work for a good compromise between speed and finish. 10mm would be the thinnest stock you would want to try at 15 tpi.
For stock under 1/2" (sorry, we 'Muricans aren't up to date yet) I use a Crown 10" saw at 17 tpi. I can't do a very good job sharpening this, I'd hate to try to sharpen anything finer.
On saws with teeth finer than 15 tpi I do not set the teeth. You get a tiny bit of set from the filing. After all, if the stock is 10mm thick you are only cutting 10mm deep so how much could it bind?
I've never tried dovetailing anything thinner than 3/8" but if I did, I would try these Zona sawsand just scrap them when they got dull.

bugbear · 29 May 2008

Roger Nixon":34r1frld said:
I've never tried dovetailing anything thinner than 3/8" but if I did, I would try these Zona sawsand just scrap them when they got dull.

I dimly recall an article long ago in a UK magazine.

It described making small saw by fitting handles to a short section of a frame mitre saw blade;

http://www.axminster.co.uk/product-Nobe ... -22818.htm

(note range of blades available)

I don't recall wether the magazine design had a back, or wether it was push/pull cutting stroke.

BugBear