Thread: Saw sharpening files 101

Here are the three Liogier Needle Files. Top - Bastard, middle - Medium, Bottom - Smooth (the files aren't bent - that's distortion from the camera lens a supermacro)




The faces are 4mm across.

The teeth per centimetre counts are (measured down the axis of the file, not perpendicular to the cuts):
Bastard 26 tpc
Medium 32 tpc
Smooth 32 tpc

What's that you say? How can a Medium and a Smooth be the same count?

Well clearly there is an upper limit on the number of tpc that can be cut, and if you look closely you can see that the angle of the teeth is steeper (to the axis of the file) on the smooth, therefore creating a smoother filing effect. I have demonstrated this to myself with a Float verses a Milled file for cutting finishing timber. The Float has teeth that are perpendicular to the file axis and therefore cut straight across the timber, but the milled file has the same 72* angled teeth as normal files, and so cut obliquely across the timber and yield a smoother effect.

So (and without having confirmed this with the manufacturer) the Medium Needle File is turned into a Smooth by simply making the angle of the teeth closer to the axis of the file, with the same tpc.

This picture shows it very clearly (Smooth at the top, Medium at the bottom):




I also counted the teeth on the 100mm EST file, and they are 22 tpc. Again this was measured down the axis. If I had measured them perpendicular to the teeth it would have been 26-27 tpc. I saw a diagram somewhere yesterday that said this is how they are supposed to be measured (perpendicular) but I'm buggered if I can find it again.This is in contrast to what Pferd say in the page I have quoted below, but I'm certain the other diagram I saw was in a Pferd publication, so I'm a bit confused on that one.

This is an extract from a post by IanW about 18 months ago:

I am less than impressed by the quality of small triangular files available these days. My main gripe is the corners. A 4" double-extra-slim (DEST) file is supposed to be good for teeth sizes down to around 18tpi, but the ones available now are most certainly NOT suitable.

Comparing 4 files: I marked out a strip of 19 tpi teeth and went at them with 4 different files

• Vallorbe needle file
• Liogier 100mm EST
• Nicholson 100mm DEST
• Grobet supplied by LV Aust as the equivalent of a 4” DEST

The results are pretty revealing, and I think these pictures demonstrate it very clearly. The Liogier cut perfect teeth (and leaves a clean surface because it is a single-cut as opposed to the double-cut needle file). The gullet is pretty much identical to that left by the needle file, and quite satisfactory. Both the Grobet & Nicholson gave an unsatisfactory result - all gullet & dinky little teeth. Worse, and this is more noticeable with the Nicholson, the corners are so irregularly cut, they repeatedly catch on the saw plate as you try to file, so it's extremely difficult to make the smooth, strokes you need to cut regular teeth, because no two strokes end up alike. Even with a fairly quick effort, the teeth cut with the Vallorbe & Liogier are reasonably accurate, because the corners on both are neat & regular and cut smoothly.

Vallorbe Needle File result:




Liogier 100mm EST result:




Nicholson 100mm DEST result:




Grobet equivalent of a 4” DEST:





The files themselves (missing the Grobet):
Left - Vallorbe, Middle - Liogier, right - Nicholson






You can read the whole story here.

I've looked at about a dozen sites of retailers carrying bahco files here, and only one of them (the first one) carries their Triangular Saw Files:
TOOLMART in Perth (they can post)

However, don't get too excited, as the range is:
150mm Slim Taper $12.95 with plastic handle
150mm Extra Slim Taper $12.95 wph
125mm Slim Taper $11.95 wph
125mm Extra Slim Taper $12.00 wph
100mm Slim Taper $11.50 wph

So no EST or DEST in 100mm.

However, looking at the Bahco parent site, they have (unhandled, in packs of 10 I think)
Slim 100, 112, 125, 150, 175, 200mm
Extra Slim 100, 112, 125, 150, 175mm
Double Extra Slim 125, 150mm

I think I may have found the Australian Distributor.

I have his card somewhere, I had a chat to him at the TWWS. I'll have a rummage.

I've just finished a conversation with the National Sales Manager of SNA Europe (Aust) and can confirm that the Bahco Triangular Taper files that are brought into Australia are as follows (either in packs of 10 without handles or as individuals with a fused on handle):

• Regular - 150, 175, 200, 250mm (6,7,8,10")
• Slim - 100, 125, 150, 175, 200mm (4,5,6,7,8")
• Extra Slim - 100,125,150, 175mm (4,5,6,7")
• Double Extra Slim - 125,150mm (5,6")

This is the entire range of TT files that Bahco make, so that's good news.

Still no 100mm DEST I'm afraid Derek, but Bahco don't make them anyway. It's starting to look like the only locally available solution there is Needle Files.

I'm about to send him an email.

Thanks for trying Brett. That info is very helpful. I wonder whether Paul Sellers, who raves about the Bahco, is using a 4" DEST? I must check.

Regards from Perth

Derek

He was using one of those double ended gizmos that come with a wooden handle. That may have changed since the blog entry. Bahco don't make 4" DEST at all (for some reason - it's the same face dimension as a needle).

EDIT: The face dimension of the Double ender is 6mm, so "Slim" at best.

This is an extract from the current Bahco Catalogue:



There are a couple of points to note:

• They are described as 3 Square (i.e. the edges are NOT toothed, and therefore not usually desirable for Saw Sharpening - a sharp "V" gullet is a stress point), HOWEVER, the diagram clearly shows that the edges are toothed - I suspect that the diagram is incorrect, not the fact that they are 3 Square.
• Confusion reigns absolutely supreme - you will see that they describe Cut 1 = Second Cut, but Cut 2 = Smooth. Best we stick with MEDIUM eh? Sheesh!
• This confusion is further exacerbated by 2 = Smooth, 4 = Dead Smooth. Ah, what happened to 3 = Something (and what's between Smooth and Dead Smooth - "Really Smooth, but not dead yet" perhaps? )

Other (good) points to note:

• They have supplied the teeth per centimetre count
• Face widths (depending on length) are 3.3, 3.8 and 4.3mm so are well suited to Dovetail Saws with high tpi count. The fact that they are Double Cut will be lessened by the very high file tooth count of 48 tpc for the Dead Smooths (to finish with).

Originally Posted by FenceFurniture

.....Still no 100mm DEST I'm afraid Derek, but Bahco don't make them anyway. It's starting to look like the only locally available solution there is Needle Files....

Brett - the slimness (face width) of the file isn't of itself the real issue for very small teeth. That matters only insofar as the width is tied to the sharpness of those corners. What I noticed with the Liogiers I tested (particularly the first lot), was that they were noticeably sharper than Nicholson equivalents (i.e. of similar lengths & face widths). So a BAHCO 100mm slim might be sharp enough to handle very small teeth. The 5" DEST might also be sharp enough to do the job. It's interesting that no manufacturer provides data on the corner radiuses of their files, at least not where I have been able to find, it. They must have internal standards & tolerances, but they don't seem to make this info public, which is a pity, 'cos it would save much uncertainty when trying to compare files within & between brands. Perhaps the best way to answer the questions is to get hold of a couple of Bahcos & give them a test run - that would soon settle the question in my mind, at least.

I was thinking that Bahco must cater for European small saw sharpeners, but maybe not - perhaps it's such a small market segment that their accountants have ruled them out....

Cheers,

Originally Posted by IanW

Brett - the slimness (face width) of the file isn't of itself the real issue for very small teeth. That matters only insofar as the width is tied to the sharpness of those corners.

Yes, understood. One is supposed to go with the other, but as you well and truly know.....

Originally Posted by IanW

Perhaps the best way to answer the questions is to get hold of a couple of Bahcos & give them a test run

I'm onto it


I was going to post this bit anyway:
I notice in your pic of the 19 tpi Teeth by Liogier that that are not quite as well formed as those by Vallorbe. I imagine that this is because of the same thing we're talking about above - looks to me like you just exceeded the tpi limit for the Liogier 100mm EST, but the Vallorbe teeth were still ok because of the narrower corners (tied in with the narrower face).

Perhaps the upper limit for the Liogier is about 17 tpi (still pretty good for a 100mm EST)?

Here is my reasoning on this:

At the top of the first pic is Smooth Engineer's File 100mm long (Double Cut as you can easily see)
In the middle is used 100mm Extra Slim Taper (Medium)
At the bottom is slightly used Smooth Needle File (Double Cut, but I can't see any evidence of more than one - that's the key point)

These are all Liogier files.

The important thing to note is that the edge of the Needle has been cut - it is NOT a 3 Square (maybe it was supposed to be - dunno - but it's cut on the edge).




In this next pic we have just the face of the 100mm EST (Single Cut)




And here we have the face of the Needle. Can you see any evidence of the second cut? I can't.




Both pics shown at the same magnification.

Also worth noting that the 100mm EST is cut at 22 tpc, and the Needle is 32 tpc (counting them with the point of a compass, so could be a little inaccurate), so the Needle *should* give a superior finish to the EST.


So maybe the Needle file will give Ian a result, as long as the edge teeth are up to the job.

Originally Posted by FenceFurniture

.....I notice in your pic of the 19 tpi Teeth by Liogier that that are not quite as well formed as those by Vallorbe. I imagine that this is because of the same thing we're talking about above - looks to me like you just exceeded the tpi limit for the Liogier 100mm EST, but the Vallorbe teeth were still ok because of the narrower corners (tied in with the narrower face).

Brett, I think the main difference in this instance is my filing - the corner radii of the Vallorbe & Liogier are too close for my eye to pick a difference. Blowing the pics up like you have done sure shows up the flaws, but I did all those demo sets very quickly, without the same degree of care I would apply to a 'real' set of teeth. What I was really interested in demonstrating was the differences in the radii of the files & hence the gullets they leave. But as it happened, it really showed how important it is for a file to cut smoothly & consistently, which is mainly why a couple of files left such erratic teeth.

I have to say that the Vallorbe needle files deliver the goods for me - they cut fast & they cut evenly, which makes the task of saw-sharpening sooo much easier. As to minimum size of tooth, I think both of the better files are ok up to at least 20tpi. The main problem I have is that over 18tpi is becoming increasingly difficult for me to see properly - I have to concentrate so hard on placing the file in the right gullet that I lose my rhytmn, and the quality of the job goes down accordingly.

Cheers,

I see.

To all:
Worth noting that I have made some changes to the list of brands (a couple got shifted to the top list). I can no longer edit that post, and will have to ask Ian to do it in future, but will consolidate the posts at an appropriate time anyway.

The only brand that may still go back to the "other" list is Grobet. If they are Suisse then they can probably stay where they are (pending getting a couple in from a supplier for testing). If the are Mexican etc, then they'll probably end up shifting (not just because they are Mexican or whatever - based upon performance).

Furthermore, I have previously stated that in a Double Cut file the second layer of cuts is the lighter one. I was thinking about this when I was looking at the magnified pics, and that may not be correct - I'll have to check with Noel Liogier. What made me doubt this was:
a) looking at the depth of the main cut
b) the fact that the tooth count is determined by the second cut layer. Surely the deeper cut is the most important, and therefore what would be counted for tpc.

Originally Posted by FenceFurniture

• Grobet - has been a great Swiss made file, not all production is in Switzerland now (Mexico does some, and maybe some Sub-Continent production) Available in Australia (part range) EDIT: some doubt as to whether the are actually available here (as Grobet),
  

I purchased some Groberts from Jim Davey last week , They where labeled as "Grobert USA", No made in information.