Thread: Triangular needle files for sharpening dovetail and gent's handsaws

Looking at the Vallorbe files available via Jewellers Supplies it looks like the choice is between two files (both Cut 4 and 'Three Square') One is labelled 'needle file' and the other 'escapement file' The escapement files are roughly double the price of the needle file. The only dimension mentioned is the files overall length. Can I get by with using the Vallorbe needle file for a 21TPI dovetail sawblade ..??

Originally Posted by Ozymandiaz

Looking at the Vallorbe files available via Jewellers Supplies it looks like the choice is between two files (both Cut 4 and 'Three Square') One is labelled 'needle file' and the other 'escapement file' The escapement files are roughly double the price of the needle file. The only dimension mentioned is the files overall length. Can I get by with using the Vallorbe needle file for a 21TPI dovetail sawblade ..??

The Escapement files are 20mm shorter and that will all be in the most important part of the cutting area - reducing your stroke by 20mm. They are also a narrower body (see here), so would be a poor choice, especially at double the dough and less availability.

When you get it, you may want to snap or grind the tip off – they ain't called "needle" files for nuthin'! That point makes it rather tricky to hold with two hands (for an accurate stroke). Some people jam it into a small piece of hardwood to get a better grip on the tip end, or you could put a blob of epoxy on it.

As a Bahco dealer I found that your local Total Tools will get them in for you if you ask them. Back in April this year they ordered in for me 2 unhandled second cut Bahco 160mm Needle Three Square files (product code 2-302-16-2-0) for $9 each and I didn't have to pay for any shipping. Also 2 Bahco 150mm Double Extra Slim Taper files (4-188-06-2-0) for $9.50 each. I'm yet to get around to using them though...

Complete saw sharpening novice question coming so apologies in advance.

If i am looking to just refresh a couple of veritas carcass saws (tpi 12 -14), would I be needing the cut #4 bahco needle files assuming total tools can order them in?

I too am a complete novice to saw sharpening so some of our more experienced members may like to answer this, however it appears from here Bad Axe Saw Sharpening Files by Friedrich Dick that you would need a 4" double extra slim file for the 12tpi (13ppi) saw and a 160mm needle file for the 14tpi (15ppi) saw.

Bahco don't seem to make a 4" double extra slim file (see p.29 here https://media.bahco.com/media/media-...compressed.pdf) but perhaps a 5" would work, I'm not sure. 5" double extra slim files are available in Australia (product code 4-188-05-2-0) The Australian catalogue is here: https://media.bahco.com/media/media-...0Catalogue.pdf

The 160mm needle 3-square files are also available here with the product code 2-302-16-2-0. My local Total Tools were able to get these needle files in for me.

In needle files, Vallorbe (aka Glardon) are the benchmark.

Originally Posted by mannetje

I too am a complete novice to saw sharpening so some of our more experienced members may like to answer this, however it appears from here Bad Axe Saw Sharpening Files by Friedrich Dick that you would need a 4" double extra slim file for the 12tpi (13ppi) saw and a 160mm needle file for the 14tpi (15ppi) saw.

Bahco don't seem to make a 4" double extra slim file (see p.29 here https://media.bahco.com/media/media-...compressed.pdf) but perhaps a 5" would work, I'm not sure. 5" double extra slim files are available in Australia (product code 4-188-05-2-0) The Australian catalogue is here: https://media.bahco.com/media/media-...0Catalogue.pdf

The 160mm needle 3-square files are also available here with the product code 2-302-16-2-0. My local Total Tools were able to get these needle files in for me.

Thanks Mannetje,

That makes sense for the size of the file required.

From what people have been saying in the thread so far, the cut off the file needs to be considered. This ranges from 0 (rough) to 4 (extra fine), at least for woodworker's requirements.

I can understand using just #4 on the 18tpi and above dovetail saws due to the teeth size, but unsure on the slightly larger teeth I'm looking at touching up.

Regards,

Adam

Originally Posted by taz01

From what people have been saying in the thread so far, the cut off the file needs to be considered. This ranges from 0 (rough) to 4 (extra fine), at least for woodworker's requirements.

A #4 Needle file is fine for touching up - you would only want #0 or #2 for cutting new teeth, and then finish them with a #4.

Without trying to dive too deep:
Saw files are single cut, meaning the teeth of the file are cut in one direction only (at 72° to the side, from memory), so each tooth is like a chisel, and this results in a nice smooth finish on the saw tooth.
Engineer's files, and Needle files, are double cut with the second cut creating a cross-hatch pattern of teeth. The second cut of teeth is not usually as deep as the first. That cross-hatch pattern results in a less-smooth surface, because the teeth are more or less points, rather than chisels. If you look up near the shoulder of a double cut file you can see where the second cuts stop, and there is a small triangle of just the first cut.

From what I can tell Adam, it appears that second cut files are the way to go with saw sharpening, but someone experienced may need to advise on that.

Originally Posted by mannetje

From what I can tell Adam, it appears that second cut files are the way to go with saw sharpening, but someone experienced may need to advise on that.

It's a moot point mannetje, because about the only cut you'll easily get in most files suitable for saw sharpening will be 2nd cuts, i.e., intermediate between a "smooth" & "bastard". This is quite ok for saw sharpening. It seems logical that a finer file will leave a cleaner & 'sharper' edge, which is desirable, but in practice I could detect no difference between teeth sharpened with very fine files (in this case #6 needle files, which leave a very smooth surface despite being double-cut), either in apparent sharpness or durability of the edges.

And yes, the 5" Bahco XXS files are suitable for 12 tpi and even an XS would do (imo, 4"DES files would be unnecessarily fine for 12 tpi). It is not desirable to make gullets too "sharp", they should be radiused at the bottom and the radius should increase proportionally with size of tooth. If the gullet comes to a sharp point, it will become a stress point that could lead to cracking. I have never seen stress cracks in small saw teeth, but have certainly come across them in larger saws. That's not to say they won't ever occur, but for a couple of reasons I think stress cracking from too-sharp gullets is unlikely in small saws unless they are treated very roughly.

As I said previously, if you use a file that is somewhere close to the size recommended for the tpi of your saw, you will be fine. The table given on the Lie-Nielsen page or here are both close enough for all practical purposes....

That vintagesaws 'treatise' linked to is still one of the best introductions around for a beginner, imo - it explains things very clearly, & you should have few problems if you follow it to the letter. Down the track, as you gain experience & confidence, you can experiment & introduce different rake-angles & amount of set, etc., but I predict that in the long haul, you'll come back to something pretty close to what's recommended, for most of your saws.

Least that's how it all happened for me......
Cheers,

Thanks Ian, I was hoping you would weigh in.

OP here, I have a supplementary question.

What differences are there, if any, between a dovetail saw and a 'Gent's Saw' ... ??

Originally Posted by Ozymandiaz

OP here, I have a supplementary question.

What differences are there, if any, between a dovetail saw and a 'Gent's Saw' ... ??

You probably should have asked this one in a new thread, Oz, there could be a lot of opinions coming in!

Saw terminology is a very inexact science, so you'll get all sorts of arguments about what the "proper" names are depending on your country and the folks you learbt from. In a nutshell, a "gent's saw" is any small backsaw with a 'knife' handle. (OK, so I accept that roughly describes many Japanese style saws, but they cut on the pull stroke whereas "gent's" saws, being of British origin cut on the push stroke.)

You can use any saw you like for cutting dovetails, there is no universally agreed-on type, design or size. I've seen just about any saw you can think of used for the purpose. The Europeans prefer their frame saws (bowsaws) and one bloke I saw used a hacksaw!

Generally one would choose a smaller saw for cutting furniture-sized D/T's, say 200-250mm and toothed somewhere between 12 & 20 tpi (& generally "rip" profile), but if cutting dovetails for a workbench, say, you would be reaching for something a bit larger, longer & with larger fangs.

Years ago, when I first discovered the effect the angle of the handle grip ("hang angle"), can have, I thought I had discovered a universal law - that a "dovetail" saw, because it tends to be used at a level above normal bench height, should have a high hang angle (i.e. the grip part is more vertical wrt the tooth line), but I've since discovered there is very wide opinion on that score, too.

My most favouritist D/T saw has a 220mm long, ~0.4mm thick blade toothed at 15tpi, and a very high hang-angle:
9 yrs on.jpg

About half of the other folks I've canvassed prefer a less-vertical handle and/or finer teeth, like this saw modelled after a small saw by Kenyon:
Baby Kenyon 2.jpg

And one chap, who does very presentable reproduction work preferred a whopping 275mm blade with a huge handle to match (he has large hands): WW D_T.jpg

And so on......

Cheers,

I think Ian's reference to an inexact science is probably spot on.

Generally speaking today we think of a dovetail saw as being a small saw with multiple small teeth, but it need not be. I am not sure when the term "gentlemen's" saw came in. Consider this page from a 1916 Simonds catalogue:

Simonds dovetail saws 1916.jpg

The No.169 and the No.170 have identical specifications other than the handle (ignore the No.166 as that is another kettle of fish and if anything more mysterious). Note that although today we would call the No.166 a gentlemen's saw or gent's saw, it was not named that way back in 1916. Conventional handles used on small saws tended to be open as a closed handle is larger (actually just extends further down) and can get in the way of sawing operations. The blades on both these saws pictured were only 1½" deep: They were intended for fine work.

As Ian points out, large dovetails are better served by a bigger saw altogether.

Regards
Paul