rip d/t tpi?

[ivan]

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? I have put a bit of fleam at the toe to make starting easier.(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? Copy an 18 tpi hacksaw blade? I don't want to waste steel by too much trial and error, so hints gratefully rec'd!!

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

[mel]

interesting thread Ivan
i would suggest that a lack of replys is due to people not sharpening there own saws . or recutting the teeth .
im affraid its an art form almost forgotten
i wonder if Alf has missed this thread , as i would have expected some contribution / input from her

mel

[dunbarhamlin]

All new New World DT saws seem to come at around 15tpi, presumably because they traditionally use heavier drawer sides.

The optimum configuration is often quoted as 8 teeth in the cut (balancing number of active cutting edges against volume of waste that the gullets can carry out of the cut)
So the ideal in any situation will depend on the length of cut - so if you gang drawer sides together, or want to use the saw for (thicker) casework DTs, or for sliding DTs, sparse may be better.

The other consideration is cleanliness of cut - certainly the way I sharpen at the mo, higher tpi does produce a finer finish (not sure of the logic behind this, as I do stone, so set shouldn't be uneven - though this difference isn't apparent to me with untouched Mike's teeth.)

Cheers
Steve

[Alf]

Sorry, I must have missed it. Not that my answer would be much help - I tend not to go below 15ppi simply because I absolutely loathe sharpening anything finer. I find too aggressive a rake on 15ppi more of an issue than lack of teeth.

Cheers, Alf

[joelmoskowitz]

Jun 25, 2008 13:11:12 GMT dunbarhamlin said:

All new New World DT saws seem to come at around 15tpi,

The Gramercy Tools Dovetail Saw (made in Brooklyn) is an exception at 18tpi, which is much more appropriate for thinner stock and cuts fine (and I think is more desirable) on thicker stock too.
If you do decided to file your own saw 18 or greater TPI use a needle file not a 4" xx the difference is that a saw file (4"xx included) has flats on each apex of the triangle and for fine pitched saws you end up with a very shallow gullet. If you use a needle file (which comes almost to a point at the apex of the file) you get much deeper gullets that allow you to cut fast even in 5/8" or 3/4" stock and for thinner stock it's a no-brainer

[paulchapman]

Welcome, Joel.

Cheers

Paul

[dunbarhamlin]

Oops - forgot that (it's a goodun too.) Thanks Joel
Steve

[joelmoskowitz]

Incidentally Ray Iles will be stocking the Gramercy saw in a week or so you don't have to order from the US.

[robo]

Oh dear I was hoping to visit you in November and take one back with me?

R

[joelmoskowitz]

Don't worry - we still welcome visitors and by November we will also have carcass saws.

joel

[ivan]

Belated thanks to all for your advice, delayed by 'er indoors' hospitalisation for keyhole surgery (not seious, revovering well) Will try a needlefile recut to 18tpi guided by hacksaw blade, with a bit less rake than my Adria. The gullets on this come to a point, so probably needle filed too.