Thread: Saw file guide

Hi Ian

I will guarantee my saw will not be a world beater.....

Have started attempting to taper a hard point saw plate plate ..

Equipment for the grind

• 100mm deep corundum drum - set up on drill press
• A linear rail that I use for surface grinding with the said drum

Initial results - looks like the drum takes about 0.05mm off the plate for about 15 minutes of grinding

Statergy

• aiming (arbitary reasons) to reduce the top to 0.15 to 0.2mm thinner
• concept brand in 10 stages . 10mm deep
• each stage gets 3 minutes grind
• so the top is grinded for 30 minutes total the next level 27 minutes and so on

Then I guess see what happens -

I admire your ingenuity Martin - it's great how people think up ways around lack of "proper" machinery. Rob Streeper posted a method some years back, and subsequently posted again here. You might find these helpful.

Derek has also had a go with what he thought were mixed results.

I once tried to put a bit of taper on a plate by hand with coarse W&D but gave up when my shoulder & elbow screamed "enough!" and the amount of metal I'd removed didn't even register on my digital calipers! It was probably about the time of Derek's thread, which might explain my somewhat "sour grapes" post.

Anyway, it's a worthy experiment, & as RayG pointed out, we never fail, we just successfully find ways that don't work.
Keep us in the loop & show us a pic of your set-up sometime. Who knows? I may get the bug to re-visit saw tapering myself, some day.

Cheers,
Ian

Martin

Taper grinding was common, in fact almost obligatory, on the up market saws of the late 19th and early 20th centuries, but not often seen on backsaws. I think Disston's No.77 may have been the only taper ground backsaw. This will give you some idea of taper grinding on a back saw from a Simonds 1916 publication, but is typical.

Simonds taper grinding. Handsaw.jpg

On a back saw the grinding may go the full length of the plate, but then again it may not. Taper grinding taken all the way may lead to a sloppy fit of the handle as it would be difficult to make a tapered kerf in the handle.

Regards
Paul

I think you made a typo, Paul - your diagram looks to be for a handsaw, not a backsaw....?

Originally Posted by IanW

I think you made a typo, Paul - your diagram looks to be for a handsaw, not a backsaw....?

True. I should have said not a backsaw!

Thank you.

Regards
Paul

Hi Paul

Wouldn't the set cause some slop as well?

Images of the crude grinder setup. It is not ideal. Peferable to support the grinding wheel with bearing each side and shim so there is slight taper . That way the the whole plate could be ground strait to taper, easier.

The hammer was used make "fine" adjustments top block to ensure it parallel to the linear slide

As mentioned the setup was previously used to level the soles of planes.
IMG_5496.jpgIMG_5497 2.jpg

Ground at bit more after work but didn't believe may own measurements- too short time grinding and too much effort put into measuring.. Caliper suggests about 0.1mm taper, but would like more-another grind tomorrow...

Martin

An ideal set up would be no set and no taper grinding, but that would result in the saw being virtually immovable as soon as you pass the teeth. Set was the next step to enable the saw to cut, but this increases the width of the kerf. A wider kerf results in more wood wasted and more effort required to cut the kerf. To some extent a wider kerf allows minor corrections in direction as we saw.

Taper grinding allowed the set to be less than if the blade was not ground thinner towards the back. A typical 26" handsaw is .036" at the tooth line. It requires this thickness of plate to maintain a reasonable stiffness over the saw's length. taper grinding varies from manufacturer to manufacturer and indeed model to model. As the Simonds diagram above shows .025" at the top of the toes would be representative, but occasionally a saw like this might be ground to .021".

I don't have a Disston No.77 so I don't know what sort of taper was given to that. All the no set saws went out with strict instructions to only use them on seasoned timber. Green timber fluffs too much. The only no-set saws I have are Simonds. There is a little about them here ( post #314) and I should add my statement expecting .039" is wrong. I would expect .036" as I mentioned above. I only know what I have read about the other manufacturers' no-set saws. Disston, Atkins, Simonds and maybe Bishop (I would need to check that) all had one or two no-set saws.

Certainly sawing with no-set needs the start of the cut to be very accurate as it is difficult to make minor changes of course as there is virtually no "wiggle" room. Having said that, if you start straight and true the saw will tend to keep you on that line assuming your sharpening is good.

Your grinding method is interesting and I am looking forward to seeing the results.

Regards
Paul

Ps: What grit/grits are you using on the drum sander?

Morning Martin, I had a 77 that belongs to Fergiz01 in my hands for a while, so I went looking for the thread to see if I'd measured the plate thickness, but if I did I didn't mention it in the thread as far as I could see. That's a bit surprising, because I would have been very curious to know how much taper they had, so I'm sure I would have tried measuring it as soon as it came out of the packet. I only have a good set of digital calipers, not the long-reach mic. that Rob Streeper used to measure some saws with.

Anyway, here are a couple more threads on tapered backsaws starting with Zac's saw. A few posts in Pacman gave a link to a post on another site - the link is broken, but I think it linked to this on Wood.net. You'll have to register to see any pics. Further down the page Rob gives plate thickness measurements for a Wenzloff copy of the 77. While that's not the same as measuring the original, Wenzloff likely followed the 77 specs closely in that respect.

After sharpening Zac's saw I had to waste spend some more time fooling about with "extreme" fleam angles to satisfy my curiosity and reported on it here. In the chit-chat, Rob Streeper talks about adding slope to the bevel (bevel = fleam in Disston language) and I said I'd take a look at that sometime. I didn't try it on a saw, I just filed some teeth on a bit of scrap to see how it went. It didn't go well, I found it extremely difficult to maintain any consistency, and teeth filed with slope lack the fore/aft symmetry of teeth filed with the file kept level (mentioned by Daryl Weir, which I'd forgotten 'til I reread the thread). Disston explicitly says to keep the file level, btw, and I guess Henry's boys knew a thing or two about filing saws...

I should state that after some (limited) experimenting a few years back, I quit filing with "slope" on any saw. I could not demonstrate to my satisfaction that it had any noticeable beneficial effects on saw performance, and it was just one more darned angle to try & keep consistent. It does look 'interesting' when viewed from the side (if done well, like one of Paul's saws he showed me that was sharpened by an American pro), but for someone who doesn't file saws every day it just adds to the difficulty, imo...

Cheers,

Thanks Ian Paul


The grinding drums are coarsish.. But I took a look at some of the plane that I levelled and they are fairly smooth - maybe 150 grit sandpaper equivalent?? It a bit hard to be sure, as you grind "lightly" for a better finish....

The drum grinders are intended for fitting an 100mm angle grinder As such they have an M10 thread. Stacked a couple together to make a wider drum.

Progress..

The setup has taper the plate from 0.8mm to about 0.53mm if the caliper is to be believed... Read through the thread Ian suggested and this somewhat steeper taper than Mike Wenzloff saw, as measured..


For those interested in production times the time spent grinding total about 45 minutes.. Stopped at least 4 x to measured taper - that's where time went..

One problem passed...

Tried file new teeth to a 45 degree fleam and almost jagged it but....
At the start of the process I was clearing think about any problem other filing. Obliterated one tooth and had at least 4 too low on one side. Remaining 2/3's of the saw was fine, when I kept my mind on the job..

Many opinions at this point....

Started reforming. Concluded that reforming is tricky. Will try again maybe tomorrow with my wife's jewellery magnifiers and see if I have a hope of sorting it...

Martin, once I could easily see 12tpi to file it, but those days are long gone. About the only saw I would attempt to file without my headband magnifier these days is my 3-5tpi rip saw!

Just to clarify something - I assume you formed the teeth first before trying to file in the fleam? The way your post reads implies you might have been trying to form the teeth & file the fleam all at once. If that's what you did, I take my hat off to you for getting anything remotely like a decent set of teeth! I have seen a bloke in a u-tube video cleaning up an old saw with very uneven teeth - he was working along from one side doing every tooth, evening them up & twisting the file back & forth to the opposite fleam angles, whilst talking non-stop to the camera! I expected to see a right mess when he was finished, but he ended up with a perfect set of beautifully filed fangs. A very impressive display of skill that I could never hope to emulate!

You have bitten off a big chunk to chew by starting with these 'extreme fleam' teeth. Filing a regular crosscut is tricky enough for most beginners, but I reckon filing those 45* teeth to be the most difficult challenge I've met. Keeping them even each side was the hardest part, mostly because the file covers the gullet completely & makes it hard to see what's actually happening, so you have to rely on feel more than sight. I've done it too few times to develop any real knack, so can't give you any useful tips. A couple more goes & you'll be the "extreme fleam" authority on our forum.....

Cheers,

Yup a bit much too chew - but I have 4x nice sharp carcass saws so I cannot sharpen those again.....

Managed to get something sorted.

Reforming teeth is beyond my skill- abandoned that approach.

Shaved off the teeth, made a self indexing saw and recut new teeth. Filed and beveled the said teeth - aiming at 45 degree flem. The result is not 100% consistent but it does cut and pretty aggressive too...

Performance
The handle and back of the original hard point saw flexes quite a bit - well rather alot ,really.
My guess is that saw would cut faster again with stiff back and well connected handle, and would certainly feel nicer..

Off the saw there is a glassy finish. It looks "odd" as I rarely noticed glassy finishes on endgrain. The sheen repeated on couple of wood types
There are slight lines visible but I cannot feel them.
Rip cuts ok as well.... The rip cut had a planed surface look to it - (on sample size of one rip cut).. I did not notice lines on the rip cut..



PS : the freshly saw will not go into the annuals of the worlds finest sharping effort. All say about is it works, cuts fast, leaves clean surface but the teeth not pretty.

Well you done real good getting as far as you have, I reckon, but we need a pic or two! Especially your method for re-cutting the teeth - any & all methods for doing that accurately (& quickly!) are welcomed, especially if it saves precious file life. Filing a set of teeth on bare plate is a real file killer!. I wouldn't worry in the least if there are a few marks on the cut surface, they may be from a slight burr on a tooth or two, or even slight wobble or flexing of the saw. If it cuts straight & clean you've made a great leap forward.

The "back" on any of the hard-points I've recycled were next to useless, just decorations. They were hardly thicker than a typical jam tin and would have added very little to overall stiffness, they rely on their relatively thick plate (usually ~0.025") for stiffness. A back with a bit of weight to it gives the saw 'balance' as much as stiffening it. And apart from the yucky feel of plastic handles, they are usually placed a bit high for my likings, the saw feels like it wants to tip forward. I prefer them to be a bit lower down so I'm pushing more directly behind the mid point of the blade. I wrote up a bit of fun I had with a couple of hard-points that I re-purposed here.

If you want to pursue this, maybe I can help you organise a decent back for your 'new' saw....

Cheers,
Ian

Hi Ian

Taper backsaw useage comments

• the tapered saw is really smooth to use
• rip cuts in particular are very smooth and quite fast
• cross cuts are rapid
• plays well with saw guides, magnetic or block - kerf has a habit of messing with accuracy slightly when using guides..
  
  • Guides are a good thing IMO - I can cut pretty well but not at the accuracy that machines can be and guides help..
  
  
• the sides if the plate feel smoother then my other saws - result of grinding....
• As previously noted the surface finish is substantially improved

Pictures of finish of a rip cut , end cut and one of accuracy in rip..IMG_5511.jpgIMG_5508.jpg

Would I use this saw in preference to others - it is looking like the answer is yes, maybe strongly..

Next the indexing saw - these idea was introduced to me from this YouTube from would by wright Why I Have C Clamps On My Saw Cutting Teeth - YouTube . He has another video the following week on another idea for indexing..


The first version I made indexed accurately but depth control was imperfect.



I have provided photos of the next version.

• This version has two hacksaw blades on the support pin.
• One from Sutton and a black one from craftright.
• The craftright hole centres is tad shorter that the Sutton hole centres.
• With a round diamond file,moved the hole position, on a diagonal. This allows the non cutting side to sit at a tad lower than the Sutton on the far side of the saw.
• The craftwright is at slight taper angle to the Sutton and is lower on the far side of the saw.
• the craftright is guide only - hence why the non cutting side is facing down)
• Between the the two blades is timber shim to set TPI spacing.
• The shim also a cut depth stop.
• The whole thing is clamped together with "pegs"

To use

• Cut a notch where you like to start from.
• Place the low portion on the craftright blade in notch and with short strokes start the cut at this start the cut.
• Once the new cut is established move the cutting to the other end of saw and cut to depth..

The repeat on the newly cut notch...

Best to check the depth cut suits you file. Easy to go to deep...

IMG_5513.jpgIMG_5512.jpg

Happy to discuss a trade of tapered saw plate for saw parts, if your interested. Will talk to Boyne Springs to see if they can supply suitable 1095 plate...

OK Martin, gotcha. I was struggling to get the concept from your description, but the penny dropped once I saw the video. A good bit of lateral thinking and should certainly help get tooth spacing even. You might struggle a bit if making really fine teeth this way but should work well in the 8-12tpi range.

Interesting that after going to so much trouble to get the spacing perfect with his jig, the demonstrator used his file "free-hand" to form the teeth (& they looked pretty good in the brief view he gave us). Someone who has filed a lot of saws can do that easily, but when starting out, most people need some sort of guide to help maintain a constant rake angle. You can buy fancy saw-filing guides but a stick guide like I showed above works just as well & costs a lot less.

I'm intrigued you find your saw works so well for ripping. It's only ever mentioned in the context of cross-cutting in all the old blurbs on the 77. I never even tried it on a rip cut when I had Zac's saw in my hands. I would have thought it would not rip well at all with that tooth pattern, but there you go - things don't always follow what we expect.

I was briefly tempted by your offer of a swap, but I've sworn black & blue I'm not making any more saws. Still quite happy to slot you a back for cost & postage though, if you want...
Cheers,
Ian