Filing Brutalised Saw Teeth

I must have bought it years ago, this 1960s 14″ tenon saw. Probably a find in a car boot sale or something. Anyway, I pulled from my shelf of abused subjects and thought unkind thoughts about the brute that just wore it down to this condition. My first thought was did they cut concrete blocks with it, something like that, but there was no evidence of that. The teeth were the worn parts, not the sides of the plate.

This first picture leads me to think that there should be an abused saws support society but of course saws don’t have feelings and can’t feel pain. Truth is more that I feel the pain of such insensitivity. I wonder how a man can reach an age of adulthood and take a saw to this level of harm without questioning himself. What would you say if the bruiser who owned this saw asked if he could borrow yours? I imagine his conversations with the saw. “Why won’t this thing cut?”

I took the opening step and filed a single stroke through each gullet. This is a trick I have never heard anyone shout about so I claim it as my own and give it out freely. When you look at a saw to buy look first at the teeth with regards to the gullet positions. If they are even there is a good chance that the saw was never sharpened or it was sharpened professionally. You should start to pick up on something here. Usually the gullets are mostly damaged by incorrect sharpening. The result is what is commonly known as sergeants and sappers here in the UK and cows and calfs in the US. Simply put the teeth result in one oversized tooth at the expense of an adjacent tooth which is then filed low or out altogether. These are the ones to avoid when you are new to sharpening. Look for even wear on the teeth no matter how bad. Look at the teeth in this first picture and they are really badly work and rounded. There is no way even the man with the biggest muscles could make this cut any more. But the gullets are indeed evenly spaced even though the teeth are work at the tips to a well rounded round.

I place the saw file in the bottom of the gullets and take a 2 1/2″ long stroke through each gullet, maintaining the same hand weight for even pressure as I stroke the front and back of each tooth. As you can see the teeth are developing the same sizes despite the teeth are indeed so bad.

After that first filing I began to think about profiling the teeth. This step basically changes the pitch or rake of the teeth and by this I can make a saw more or less aggressive. This usually starts with topping (Jointing USA) the saw teeth lightly with a fine, 10″ flat file first.

Now I can see exactly which teeth are high and I can file to height according to the flat tops I introduced and can now see quite clearly.

Now it is simply a question of sharpening the front and back of one tooth gullet, pressing more into the wider flat top as needed until evened out the flats. Remember you must sharpen from both sides of the tooth as if you don’t you will be creating more sergeants or sappers. Also, I think it is important not to allow intimidation about sharpening. Often, usually, even a badly sharpened saw works quite well.

Final shaping is still on its way; usually with only one stroke to each tooth gullet. The process for this saw took just four strokes across the gullets of all the teeth which gave me a good, user saw. Fifteen minutes work or thereabouts. You can do this!

Only a little finessing now. I’ll finish it tomorrow when the light’s a little better.

18 thoughts on “Filing Brutalised Saw Teeth”

  1. Plenty of great advice here to put an abused saw back to work. Thanks Paul !
    I see many old saws – mostly panel and frame saws here in France, ancient backsaws are rare – that have been neglected in various ways.
    A lot of them have a concave along the length of the blade. The teeth are often relatively even, so it could mean that they have been decently filed but never topped.
    You made an awesome video 5 years ago about « recutting and resizing saw teeth ».
    But how to know if an old saw is of quality steel and if it is worth restoring it ?
    For my part, I would say let’s do it and we’ll know, but perhaps there’s a better answer …

  2. Any saw made before the 1960s will usually be good steel. Demand for cheap tools by the west in the 60s, together with unscrupulous sales outfits, the import of low cost replication of tools with extremely low grade and poor quality tools and equipment from the then GDR came in. With unification that is all in the dim and distant past.

  3. When dealing with tall teeth, would you estimate that you remove the flat equally from the top and front of the tooth?

    This post was an Aha! moment for me. Thank you! I’ve been jointing too heavily when fixing saws! I see now that, rather than going right for a nice flat profile and then dealing with sorting out how much to file each tooth, it may be much easier to take a moderate jointing pass, leaving some or even many teeth untouched, sort out the teeth that were hit, then repeat. This will naturally cause some teeth to be filed more as you repeat. That’ seems so much better than what I’ve been doing, which is to joint heavily and have various sized flats so that one must guess how much extra to give the wider ones vs. the medium and smaller flats.

    You remove a staggering amount of material in a single 2 1/2″ stroke based upon those two photos! That would have been half a dozen strokes for me. Maybe I need more hand pressure!

    Excellent blog post! Many thanks.

    1. It is a question of gently, stealthily approaching the enemy in the land of the giants.They don’t mean to stand out. File off the tops of the highest ones and take down the big giants first; less to be overwhelmed by. File the tooth from both sides but remember too that you may want some to take off the adjacent tooth with a final stroke or two.

  4. I’m curious how you might handle the first tooth at the leading tip of the saw. It appears the first tooth is pretty much gone. Should it matter at all or will subsequent sharpening correct the shape?

    1. Yes, you can just forget it for three or four sharpenings and let the unresolved teeth emerge, or indeed you can simply file into the curve and have smaller starter teeth, which is what I have now done.

  5. Nicholas Gaudiuso

    My first tennon saw has developed obvious cows and calves. How would you handle future sharpening of such a saw? As always then you!

  6. I have had a little Thomas Turner Encore brass backed saw for many years that I didn’t use as it was blunt. Recently, but before reading your blogs, I filed it at 90 degrees across more in ignorance. It then cut beautifully but possible with a tendency to go to slightly to the right (I am left-handed). Having now seen your advice (excellent, many thanks) I realise that sharpening it as a rip was a good accident. I have resharpened it. As far as I can see it has no set. I think it is about 8 tpi. I find the prospect of set such ( to me) fine teeth daunting.

  7. Hi Paul,
    You mentioned filing the teeth from both sides. Do you do this with rip cut as well, or just cross cut? I seem to recall with rip you can file each tooth from the same side, or am I reading this incorrectly?

    1. Crosscut saw teeth must be sharpened from both sides if the intent is the pinnacle point tooth as in standard crosscut saws. Ripcuts can still be sharpened from both sides but that’s not necessary as long as you hand is steady and dead square across. Some people can develop a bias of a few degrees out of square and that then creates a problem because of course there is a biased bevel to each tooth. Practice gets you dead square.

  8. I have a saw arriving that I think from the pictures is missing one tooth dead center of the saw. Will that matter? Can I just ignore it? It is supposed to be sharp otherwise.

    1. An odd tooth missing should not be a problem but it can depend on the tooth size. On a 4ppi saw it will but no one really uses that size of handsaw any more.6pp on up and you most likely will not feel a thing. Avoid using the saw file in the missing area and it will just emerge after a few sharpenings.

  9. Hi Paul
    I bought an American Disston in a second hand tool shop some time ago.unfortunately your article had not appeared then, but I now understand why I can’t get it sharp, the gullet depths are very uneven, some 2 mms deep some four.
    What should I do?

    1. This means one of two possibilities usually. One, the file is not ‘rolled’ to the correct angle consistently so that means that the top face of the file facing uppermost changes with the strokes taken. generally it is best to keep this between dead level on top or slightly tilted forwards towards the toe of the saw. Level will give you an easy cut that grabs less but is then ` little more passive than you might want. The amount of tilt forward determines the aggression of the cut. if you want a saw that crosscuts and rips in one saw then the level-across means you can use it for both cross- and rip-cut. On the shorter saws, say up to and including the 12″ saws consider starting out at this pitch so that you effectively create an equilateral triangular tooth pattern. Use it and see how you feel. If you feel it is too passive, reload the saw in the chocks and vise and tilt the file slightly forward. This then changes the pitch. Two, and this one is worse, the filer has used uneven pressure and filed more off one tooth than the adjacent one. This can be hard to correct but you must start somewhere. Take a flat file across the tops of the teeth and make a single light pass. This results in identifying the high teeth and then the wide ones too. To file these teeth take your time and file either side of the wide teeth without if possible filing the low or narrow points to start. Once done the teeth should look more evenly sized and spaced. Now go back through all of the gullets and file sensitively as evenly as possible but willing to take more of one side of a teeth as you alone can see necessary

  10. Hi!
    I cannot understand the “One file stroke only ” trick: what Is the advantage since teeth are so bad ?

  11. Paul-are you still using a hacksaw and taking a single pass in each gullet as you wrote about a few years ago? If not, why not?

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