Teething Troubles? Retoothing Your Tenon Saw

Recutting Teeth Commercially Can be Prohibitively Expensive – Do It Yourself

A tenon saw passed to me today showed sad neglect and poor sharpening resulting in some small teeth varying between 16-18-ppi in one section and then 12-ppi just three inches further on. Surprisingly the saw did cut, but with difficulty and with sporadic progression quality ranging from bad to worse. Correcting this type of flawed filing is about impossible with a saw file alone. It needs a recut and that means sending it off and having it recut by a saw recutting machine. This machine punches out the teeth mechanically and guillotine fashion with sheer cutting to whatever size you desire for the saw. On the other hand you could use a junior hacksaw with fine teeth, a Bahco XX slim 4” saw file and 14 ppi hard frame saw or hacksaw blade to guide you. Oh, you also need a 10” single cut mill file.

The Simplicity of DIY – Don’t be Intimidated
I have several methods for recutting teeth and they all work. This is one of the best I’ve come up with yet and you end up with a saw that cuts above the rest and up with the very best of the best without doubt.
Retoothing in a home shop usually takes about half an hour or so. That’s if you have no or little experience. Locking the saw in a vise that secures the saw near to the edge gives good support for confident strokes along the length of the saw across the topes of the teeth. it’s best and easiest to remove every tooth all the way down to the bottom of the lowest gullet; starting with a clean sheet. If the saw plate is rusted at all it is best to remove all rust now and not after recutting and sharpening. 250 grit is enough to remove it.

DSC_0008
With the plate anchored, file off the teeth until a straight and even edge remains.

 

DSC_0114

Clamp the 14-ppi saw blade alongside the plate with the guide saw teeth just barely protruding above the edge of the plate edge. The tips of these teeth serve to align the file and set the distance between teeth exactly.

 

DSC_0110DSC_0105

Take the junior hacksaw and run the blade against the front of the saw teeth with two or three strokes from one end of the saw to the other. The cuts should be square across. Even pressure and equal length strokes ensures evenness in depth of cut. It’s not necessary to go to the bottom of the gullet. Angling the saw a little will give a rake to the tooth that you want. 10-degrees or so works well. Filing will finalize actual shape and size soon.

DSC_0122With the teeth positions defined and the hacksawing done, remove the guide and place the file in the first saw kerf. The top face of the triangular file should be aligned level and flat. File down evenly and half way into the face of the first tooth. This will reduce the width of the top flat to for the first tooth. Do the same to the second kerf until the first tooth you just passed is almost formed and a narrower light band is reflecting off the top flat. This then continues for the first 14 kerfs; the first inch. For the next inch roll the file slightly so that the top face leans forward by a few degrees.

From here on you can roll the file forward slightly more and keep a consistent pitch all the way through to the end of the saw. This time you will be filing the back of the tooth and only glancing the front of the adjacent tooth to polish the face with lighter strokes.

DSC_0127

It is up to you whether you shape the whole tooth to the bottom of the gullet or not. I suggest you take only a couple of strokes rather than full depth. These file strokes are dead square across the plate and the file is always leveled across the edge too with every file stroke you take. Full forming can take place when the deeper depth is achieved.
The next stage is simply filing before and aft’ each tooth. If you file the front of the teeth perpendicular, that is upright, so that the face is vertical, then the cut from the tenon saw will be aggressive. A rake to the tooth front of 10-degrees gives a good balanced cut that’s progressive and effective without being difficult to push into and through the strokes in the cut. File either side of each tooth as equally as possible and close in on the flat top until the shine disappears with the final stroke. DSC_0122The tooth will be sized and uniform and the teeth will be sharp. All that’s left now is to set the teeth.

21 comments on “Teething Troubles? Retoothing Your Tenon Saw

  1. I bought a very sorry looking dovetail saw on ebay which has way too much set from its previous owner, but also too many teeth set one way. I have hammered off almost all the set with the hammer in the vice method, but am worried about breaking a tooth which has previously been set the wrong way. Do I need to file the teeth down past the bad setting?

    • Its more rare for a tooth to break than the norm even when you redirect to the tooth the opposite to its usual direction. That being the case you can carefully tap out set and reset and redirect the teeth regardless. It’s unnecessary to file off teeth. Usually the set reduction or removal makes the saw feel better in the cut. You must have some set and actually, if the steel is a good saw steel with spring in it it will be difficult to remove all of the set using the hammer in the vise method. Tap the teeth from both sides and there will likely be enough set for a functioning saw.

      • Hammering off the majority of the set, filing so the teeth are the same height and then sharpening and the saw cuts nicely. Glad I asked before creating a great deal of extra work! Thanks Paul

      • I seen a post from the bloke who makes the bad axe saws. The way he (sorry can’t re-call his name) In the post he puts paper to thickness over both sides of the saw blade. Then places it in a vice. Theory being the correct amount of paper will not compress, thus acheiving a uniform set. Can not personaly vouch, as I’ve not tried as yet. Though the theory and reputation of the individual are both of merit. cheers Peter

  2. Dear Paul,

    I just wanted to thank you for an excellent, and in my case, perfectly timed, post.

    You see, I own a wonderful old Tyzack tenon saw, which manages to work surprisingly well despite my past (poor) efforts to sharpen it, after following some other web guru’s web video. Let’s just say, I wish I’d seen your simple progressive rip cut sharpening video sooner!

    I came to resharpen it (properly) for the first time again yesterday only to find my previous efforts had nearly removed some teeth altogether, and the heights og the others were very inconsistent. It no longer cut straight. I nearly cried. This tool had belonged to my grandfather, a woodworker who, through his furniture business in Ipswich many decades ago built barley-twist gate-leg oak tables and beds and wardrobes for the public with traditional tools and traditional joinery…He died two years ago aged 101. I thought I had ruined his saw forever, and I’m so happy to know, now that I’m a little more clued up on sharpening, all is not lost thanks to this post. It’s just what I needed!

    Paul! A hugr thank you!

  3. Hi.

    You mentioned saw with no set the you use for softwoods.

    If you are sawing very little softwood but rather very hard wood – such as you might find in Australia – how would you alter the tooth angles, spacing or set for rip and crosscut saws?

    Cheers.

    • Some saws can be set with minimal or no set depending on the work you are involved in. You can reduce and remove set too.
      Hardwoods need set but only minimal. The least set the better but some woods need less if they are for instance oily woods that self lubricate in the cut, which I suspect is what you have. There are many perspectives on teeth types but most are impractical and put out by salespeople to sell more than one saw. Almost any saw can be sharpened to cut both rip and crosscut in one saw and especially when they have teeth smaller than say 10-ppi. Hit the search button on my blog and put in saw sharpening, saw set or similar and it works really well to get you where you want to be. Also, have you seen the YouTube video here. This will help too.

  4. Geat information, Paul. What product or methods do you find best for removing the rust. I have several saws that I have recently aquired that has some rust but not real pocking. What is the best way to clean it up?
    Thanks Jim

    • I use almost any abrasive paper. I light brush over with 150 to knock of thicker rust if that’s an issue and then 250-grit for rubbing down to steel. It’s the fastest and I get what i want. i look out for engravings in the plate as I wouldn’t want to abrade that out.

  5. Hi Paul,
    I have a nice old R. Groves & Sons 14″ tenon saw. The teeth (10-11 TPI) are pretty much uniform in height except for one broken tooth midway down. It’s broken at approximately the depth of the gullets on the other teeth. Would you recommend joining the other teeth down to this height and refiling, or leave it as is.
    Thanks and best regards,
    Gary Blair
    Lander, Wyoming

    • One missing tooth rarely causes a hiccup in the passage and I usually suggest leaving everything alone. When you come to sharpening ignore the spot and as you sharpen a tooth will emerge over the next year or so depending on how long you go between sharpenings.

  6. I recently retoothed a small tenon saw/dovetail saw. I used saw filing templates you can download for free at Norse Woodsmith. Here’s the link: http://norsewoodsmith.com/content/saw-filing-templates
    It turned out very handy, especially because you can choose every possible TPI.
    I had lots of fun filing the teeth, it wasn’t perfect at all, but I did manage to cut some dovetails afterwords.

    • Thanks I was going to make some templates like the ones you mentioned here, but looks like I won’t need to! These ones fit the bill perfectly, as I don’t have another saw blade to reference from.

  7. I just got an older Disston back saw. 12″ blade with 12 tpi. The blade was in pretty rough shape – black with rust – but a couple of hours with abrasive paper got it looking pretty good. The teeth looked to be in pretty good shape surprisingly though the emblem is 95% worn off. I feel like someone used it a lot and took very good care of it, but then it got left to rust for many years.

    I sharpened it with a rip pattern and a progressive angle the first couple of inches. And then set the teeth. All of which I learned from videos here. At this point, it rips fairly well. But it won’t crosscut for anything. It gets past that first couple inches and then just slams to a stop.

    I don’t think it’s not enough set. It’s not binding in the kerf. The teeth are just grabbing the wood and stopping the saw.

    So I’m beyond my basic knowledge now. Possibilities in my mind: 1. Not sharp enough. 2. Too much set. 3. I sharpened it to rip, it’s not going to crosscut.

    Hoping it’s not 3, as it’s a pretty nice saw right now. You indicate that sharpening a saw per your videos, it should rip and crosscut fairly well.

    • Keith, from my own limited experience, I suspect that you with have no set or too much set. As you think you have enough set (i.e. #2), I would suggest removing some set using the 2 hammers technique that Paul Sellers shows in his excellent videos. Worked for me, after cleaning, sharpening & setting my wife’s American back-saw (tenon saw) it didn’t cut well at all (it stuck, even when ripping) until I removed some of the set, now it’s good 🙂

  8. Hi Paul,
    I was cutting the tooth of my S&J 8″ with the frame saw and found that the frame saw blade is too thick for cutting 16tpi.
    So I filed the S&J flat again and was trying to cut 14tpi with a cheap junior hacksaw modified as mentioned in the tutorial video.
    The problem is each kerf took me about 100 strokes to get the depth. I was wondering what junior hacksaw with which blade were you using?

Leave a Reply

Your email address will not be published. Required fields are marked *