Saved Saw and Perfect Teeth

So I added another R Groves tenon saw to my collection of working Groves saws. The eBay find was a no brainer for me because it was one I’m yet missing from my saw gatherings. There are still two or three to come that I know of and there may be others I don’t know of yet, but I’m in no sweat. At the end of the day these saws really know no equal in my view, but that’s just my opinion. I like solid, well used and proven saws that have held up for a 100 years and are not so prissy as some. These have a fineness about them I like and you can really push them to the limits. Course for some reason they keep going up in price!

I’d checked the very ugly teeth for size and shape and decidedI would need to file them all off when and if I bought the saw before I bid for it. That’s what I’ve now done. Previously it looked as though it had been an 8TPI so I filed off and retoothed to the same size. Ripcut or crosscut it would be impossible to say except that 90% of all tenon saws were sharpened for ripcut. It took me under an hour. Originally the saw had a .5mm set to each side of the teeth, many times too much for me. And because the teeth were so irregular in size, shape and set, the cut looked like a rat chewed it; ten strokes took me only to a depth of 6mm or so. That’s how bad it was.

Repairing the Horn Cracks

If you read a previous post on this issue it will help you. This saw had been dropped also onto the horns of the handle and the had slight cracks (a common issue) but both points were still fully anchored in place. I used thin superglue first, to wick into the roots of the cracks, and then I used a thicker version for the larger openness. A wedge placed appropriately pushed it fully into place and a light misting of accelerator gave me total closure. Chisel, file and knife work followed by light sanding and colouring with a brown and black Sharpie mix did the final trick of colour matching.

Broken Off Teeth

There are two common reasons resulting in tooth breakage usually, lack of or uneven tempering of the plate, leaving part or all of the plate too brittle to set and even sharpen, or oversetting the teeth. More rarely, a tooth can catch something hard and the snagging breaks off a tooth. To determine which was the case, I ran the file across the top of the teeth first. I had had to do this anyway to top (joint USA) them and get them level.

Five teeth were missing at this point but the teeth did not seem overtly hard as I expected. My next test for breakage cause was to remove the set by hammering the teeth back to surface level and out of set.

Straightening the teeth often results in more breakage and this at first thought is frustrating. Ping! pop! pop! pop! Oh, no! What have I done!?So there I was, 11 teeth broke off leaving me with no choice but to file out the whole and recut. The reason for the added breakage was the over set teeth. They were really fractured already as a result of the previous over setting, but they were hanging on. My straightening them was more consequential and not the actual cause.

Filing Off the Teeth

By filing off the teeth, within the first few strokes, I knew the hardness was fine, perfect in fact. After 20 minutes I was down to level. I used my hacksaw trick with incremental 1/8″ cuts in wood as a guide. You can see this on my YT channel here.

With the notches cut, my file dropped into exact placement for filing and half a dozen strokes to each gullet took me down close to final depth. This will vary depending on the hardness of the steel, the file and the length of stroke. Not complicated.

Recutting and Filing Teeth

I started to recut the steel with a 5″ tapered file. With my wanting a pure, aggressive ripcut it was straightforward enough and very quick to do. Not tedious at all.

Setting Teeth

From here on it was just a question of setting the teeth and because they are large teeth I simply used a sawset on the shallowest set.

The Result is Incredible

My saw sliced through the wood remarkably for about an hour’s work. It’s a lifetime saw from the 1800s and with a full length plate 4″ deep it’s good for a few hundred years yet.

Here are my tenon saws that I use on a daily basis.

Here is my phone vid showing the saw in action:

 

 

17 comments on “Saved Saw and Perfect Teeth

  1. Beautifully and expertly done. Thank you for sharing this resurrection of another formerly-mistreated, quality tool. I have a collection of antique saws in various states of disrepair that I’ve picked up here and there for $10 or so per piece intended again for regular use, but for the most part I haven’t gotten around to restoring them. This post is inspiring, and I’ve been looking forward to using your hacksaw method. Cheers from the East Coast, USA.

  2. Thanks, Paul. I’ve restored a couple of saws following your instructions. Getting a clean, straight, fast cut from a freshly sharpened saw is one of the most gratifying parts of woodworking.

    Do you have any advice for a saw with a brittle plate? I have a beautiful Drabble and Sanderson which I have attempted to re-tooth twice, but a couple of dozen teeth pop off when I try to set it. I love this saw, it fits my hand better than any other I have held, and I really want to get it working again.

    • It sounds like uneven tempering but sometimes it can be along the tooth line. I don’t know enough about steel tempering but wondered if you take the plate out of the handle and load it into the oven at I think 350f. When the parts are brittle this way they really can’t be used. As I understand it and have had success with, returning the steel to heat for further cycle at a lower temperature reduces the hardness. I don’t think you will lose anything tempering the steel this way as the heat is quite low compared to hardening levels.Of core hardness will be dependent on the carbon content of the steel and we don’t know what the alloy content is. It’s this that dictates how deep the hardness goes into the steel and so affects the mechanical properties you might expect. It’s one thing achieving surface hardness and another the core hardness and tensile strength of the the finished plate.

      • Hi Paul, Michael,
        I’m a toolmaker by trade and have done a lot of heat treatment over the years. Unless you know the exact grade of steel in the saw, tempering it is risky – the temp range band for achieving a required hardness is quite narrow and very different for different types of steel. As suggested by Paul, start at 350f (176c) but in my experience, this is quite low. Work your way up maybe 30c at a time until you get the required result. The old fashioned way is to polish up the blade to shiny bare metal and heat with a torch until the edge turns ‘straw yellow’ – but it will go darker and softer very quickly.

  3. Could you explain your method of removing the handle? Usually it’s very difficult to unscrew old split nut screws, especially if you have this medallion, how do you do that?

    The problem mostly is a loose handle, because wood is very dry. Once removed I suppose the place where saw blade enters could be patched. Or I could keep the handle on and just treat wood with something to expand it back and have handle firmly attached to the blade.

    • They can be difficult because it’s is not just a question of making the split screwdriver as I have done from an old flat screwdriver. The main problem often is that the threads are bottomed out. Applying too much force then can then break the stem on the bolt aspect. So my tip is to not try tightening first but unscrewing so that you can first see the threads on the stem to see if indeed thy have been chased to create enough length for tightening. If the bolt part can be removed readily from the hole you can test the relationship between male and female parts to measure the distance to see if indeed the two outer flanges will see with thread to spare when in place. If the threads are not long enough it is easy enough to increase the length with a small triangular file like a saw file. You can also use a hacksaw to chase more thread. A second danger is that the stem is already weak and more exertion of pressure can indeed twist off the stem. Without making a replacement this is difficult to resolve. In this case you could use a small threaded nut and bolt with say a pan head that will serve to tighten the plate and close the sides of the handle and relocate the broken halves with superglue or some other. This would be purely aesthetic on the one hand and on the other will preserve some of the value. Where three or four bolts are used two or three may well be enough to cinch everything down. On the other hand you can choose to buy replacement split nuts whether new or secondhand. Lastly, you may consider shimming out the gap with something like sandpaper. This always works and the edge of the sandpaper can be coloured to match with felt tip.

  4. In your day to day of making furniture where do you see the large 16″ 8TPI Tenon saw being used in place of say your 14″ Groves. I was considering recently the Veritas Tenon saws and they are 16 ” / 8TPI also. As we always tidy up a tenon cut ( cheek ) with a chisel / router plane / shoulder plane the more aggressive surface left by the 8TPI wouldn’t be a concern I’d imagine.

    I suppose I am trying to find an excuse to own a 16″ Tenon alongside my old 14″ S+J 😉

    • Well, surprisingly, the 8TPI cuts surprisingly smoothly because of the rigid back and the short length. i never bought a Veritas version so can’t judge it but I am sure it will be fine in both senses of the word.

      • Although an abstract thought, I’m thinking the extra weight and size of the 16″ plate saw might result in a more accurate cut on a larger tenon….a bit like how I find the #6 has more stability than my #5 in some of my work. I don’t mean weight/ bulk just for the sake of it but a tangible and useful feel of the tool. Hard to describe really…..

  5. Hi Paul,

    When you recut saw teeth, do you always use the 1/8″ increment between each tooth? I’ve seen the video multiple times and still struggle with this method. I think it’s because I’ve tried to make saws with 10 or 12 tpi. The slots on my jig fail because their too close together. By fail I mean they break apart and become big slots instead of individual one. What type of wood do recommend for the jig? I’ve used only pine.

    Anthony

    • I’ve recut 16tpi gent saw like this, the sistem works. I used a wooden template, it worked for one time, probably if I would have more to cut, I’ll use a strip of aluminium or something else. Not perfect, but with a lot of attention, good eyes it is possible. For 16 tpi practice or another method should be developed. The problem is to make all uniform, there is no room for errors and corrections for small teeth.

      My blade is not very large, should I set the saw? It is cutting without any set. I don’t have a saw set. It will be nice to see other alternative saw setting methods, I tried using nail set on bigger tooth, it works, but knowing more methods is always useful. I’ve seen there are other traditional saw sets, basically is a piece of metal with a cut, I suppose it is easy to made, and I have just to put a tooth in the cut and bend it.

  6. Very inspirational.

    I’m sitting on an 1870’s 4 1/2 ppi Bishop number 7 rip saw that’s pristine but for the teeth. When I got the saw, they were actually filed backwards as a pull saw!

    I filed them off, and an now building up the courage to tackle such big teeth.

    Any hints for those massive dentures?

  7. Just for curiosity, I’ve looked for Richard Groves saws on eBay. The cheapest one I’ve found costs 50 pounds. Even with a lot of years of life, they have the look of the well-done-tools, but I’m afraid that I must go on with my S&J saws, at least for the moment!

    My wife bought me as a present a Pax tenon saw by Thomas Flinn last year and it is a absolutely fantastic tool, but these Groves have something special…

Leave a Reply

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