In part 12 we left our intrepid sawster (Is that a word? It is now.) feeling very sorry for himself. If you haven’t read part 12, you should read that first as this is a continuation of that post.
Anyhow, you can’t keep a hand tool junkie down and suitably chastised by the saw gods, I picked myself up and worked the problem. I found out that I’d mistakenly thought the problem was what is known as ‘Cows and Calves’. However that is when the bottom of the gullets alternate between shallow and deep. I believe my problem is correctly called ‘crowding’ where the teeth are of unequal width. I believe I messed up for the following reasons:
- Rushing it and not paying enough attention to what I was doing
- Filing too aggressively.
- Not applying pressure in the right direction
Here’s how I fixed it.
I had to go back to the shaping stage again before I could try to resharpen the teeth. At first I was going to file the teeth off completely, stick a new template on the side of the plate and file in the new teeth. In the end though, I decided to try and fix the existing teeth and even out the spacing again. In this way, I wouldn’t waste any more saw plate than was absolutely necessary.
I started by jointing the teeth until the file had knocked off the top of each tooth. You can see in the following two photos that the ‘shiners’ vary in width and in the first photo, there is one tooth that the file barely touched. What a mess!
Because I’m working outside on uneven grass, I started by making sure that my Workmate was level in both directions with a spirit level. Then I clamped the saw plate in the vise and made sure that it was level using my set square as a depth gauge. This may sound a bit obsessive, but when I’m filing the teeth, I’m holding the file horizontally and my jig ensures I maintain a rake angle of 9 degrees. If the teeth aren’t level in the vise, for example they sloped down from left to right, I won’t be filing a 9 degree rake angle at all. It could be as much as 10 or 11 degrees.
Now I concentrated on each individual shiner. The idea here is to file each shiner evenly from the front of the tooth and the back of the tooth alternately until you meet in the middle. With each stroke the shiner will get thinner and thinner. As soon as it disappear, you stop filing that tooth and repeat the process on the next tooth.
When filing the front of each tooth, I applied light sideways pressure into the front face of the tooth.
When filing the back of each tooth, I applied slight downward pressure.
I kept alternating my stokes 1 – 2 – 1 – 2 etc, until each shiner just disappeared. Using this method, each tooth ended up the same width and depth irrespective of how wide each shiner was to start with.
Once I’d corrected all of the teeth, I lightly jointed them again so that each tooth had the tinniest of shiners. I then repeated the whole process to fine tune the teeth and ensure my toothline was perfectly straight.
Then I set the teeth and coloured the sides and tops of the teeth with a permanent marker.
Another light jointing and then I was ready to try sharpening them again. When sharpening, you are actually filing the front of each tooth that is leaning away from you and the back of each tooth that is leaning towards you, whilst applying slight downward pressure. If you are filing fleam into the teeth, you need to ensure that the file is kept parallel with the lines on your fleam template when sighting down over the file. Then you repeat the process from the other side of the plate. It only takes a couple of strokes on each tooth. Don’t press too hard and let the file do the work.
In what seemed like no time at all, I was done. I checked the toothline with a straightedge and blow me if it wasn’t straight. That’s more like it I thought.
So here’s the finished saw, made in 1887 and now given a new lease of life.
Now I know you guys will demand to see it cutting, so here’s a little video of me putting it though it’s paces.
All my tools have to earn their keep, so I wasted no time in putting this saw to work making a tooth guard for the saw.
First I ripped the kerf for the teeth.
Then I made a rip cut to separate the guard.
Cleaned up the sawn face with a block plane.
Chamfered all the edges.
P.S. – I used up 1/4” of saw plate by the time I’d finished with this saw, but the lessons learned are worth far more to me and I won’t make the same mistakes again in a hurry. Lesson well and truly learnt. :o)
-- Andy -- Old Chinese proverb say: "If you think something can't be done, don't interrupt man who is doing it."