Well the rain finally stopped today and the sun came out. Looking out on my garden, the squirrels were making the most of it. I sat and watched this youngster somersaulting around the garden, before settling on a branch to devour his morning pine cone.
Following his lead, I took the opportunity to get outside and sharpen another saw. Next up is the W. Tyzack, Sons & Turner No.120. Fourteen inches long with a .030” thick plate and an extra heavy spine. This is by far the heaviest backsaw that I own. If you’ve been following this blog series, you’ll remember that this is the saw where I reshaped the handle and filed in a lamb’s tongue to give it a bit more character.
Originally, it was filled 11 TPI rip, but I decided to re-tooth it to 10 TPI with 4 degrees of rake and 5 degrees of fleam. Before I could do that though, I noticed that there was a slight wave in the toothline that had to be rectified before I could start filing.
There are basically two reasons for a wavy toothline. The first is that the saw plate has slipped in the spine and the second is that the spine is slightly bent. More often than not, old backsaws that you buy at flea markets or off ebay have one or both of these problems. Many of them have either fallen on the floor, been driven over, or trodden on. If you sight along the toothline and you can see a wave, always sight along the underside of the brass back to see if you can see a corresponding bend there. A bent back is the most common cause of a wavy toothline. Chances are it won’t be much, but you need to fix it if the saw is going to be of any use. There are a number of ways to go about it and this is the method I use.
Basically I just rest the back on two blocks of wood convex side up, hold it in place with one hand and hit it with a deadblow hammer at the point where it is bent the most. I start with a light blow then check it. If it isn’t straight, I hit it harder and harder until the bend is removed.
The nice thing about this method is that most of the time, you don’t need to remove the handle. You do need to sneak up on the right amount of force though as you don’t want to bend it too far the other way. This saw took quite a blow to straighten it out due to the extra heavy spine.
So I re-toothed the plate using my template method that I’ve gone over previously and then set the teeth and sharpened them.
After sharpening, I stood the saw up (teeth down) on a granite surface and tried to slide a very thin piece of paper under the teeth all along the plate. I’m pleased to say that this is the first saw I’ve sharpened where I couldn’t get the paper under any of the teeth. Hooray! Could this be progress or just a fluke I wonder? LOL.
I haven’t really said much about saw files in this series yet, so let’s talk about them for a minute. Both of the files in the next photo are 6” double extra slim tapered files. The top one is the one I bought first and is made by Bahco. I like these files a lot and would recommend them. Saw files don’t last forever though, especially if you are using them to file in new teeth from scratch and I now need to replace this file. So that I could sharpen my saw today, I bought a 6” double-ended saw file made by Nicholson at a local hardware store, together with the uncomfortable plastic handle that the file pushes into.
I don’t like these files much. I suppose they are Ok if all you want to do is touch up a saw in order to bring it back to sharp. If you are doing any re-toothing or heavy shaping however, they afford so little movement that it takes more than double the amount of strokes to file a new tooth. I noticed that the corners are slightly more rounded than the Bahco file too.
I hesitated to buy it when I saw it said Nicholson, because not so long ago Paul Sellers pointed out on his blog that they ain’t what they used to be. He reported that the edges were just crumbling after a few strokes. This one was fine though.
Funnily enough, when I sharpened my Disston No.5 with a Bahco 5” extra slim file, two of the three edges crumbled as soon as they touched steel, so maybe this issue isn’t just confined to Nicholson. You can see what this looks like in the following two photos.
I thought I’d mention this problem because it is pointless to continue filing when this happens. If the file feels like it is grating, stop and check the edge. If you don’t, your teeth will end up in a right old mess.
Anyhow, back to the No.120. Some people say that 10 TPI is too coarse for a 14” backsaw, but l believe Lie Nielsen’s large tenon saw is 10 TPI, so I wanted to see what it was like to use. It does take a bit of getting used to (and I’m not there yet), but I think I am going to like this filing with a bit more practice.
Here’s a little video of the saw cutting a tenon cheek so you can see how it cuts. Once again, please excuse the wobbly bench.
So this is where the journey started for this saw…
…and here it is reborn.
Since this is the last of my rip backsaws, I thought I’d leave you with a rip saw family shot.
-- Andy -- Old Chinese proverb say: "If you think something can't be done, don't interrupt man who is doing it."