Guess what? I finally got my Wenzloff & Sons, Seaton tennon saw and it was worth the wait! This is the 19” inch monster. When I first tried this saw it felt too tippy to use. Chris explained that this is an advantage that helps you saw plumb. The reason is that you can use the tippy-ness of the saw to tell you when you are plumb. When you balance the saw on the work, not tipping one side or other, the saw is plumb! It is simple physics. All you have to do is move it to and fro to get a perfect cut. I know that there is a story floating around that Newton discovered gravity by watching an apple fall, but I don’t believe it. It’s more likely that a woodworker already knew this because of his saw and told Newton about it.
Anyway, I have been practicing Chris’s sawing technique for sawing tennons. I marked out a couple of tennons and started to saw. In the first picture below you can see how I have the work clamped in the vise. This way I can advance on two lines at once. The important thing is to stop when you hit the shoulder line. The picture shows where I stopped sawing. Flip the work around in the vise and do the same technique on the other side stopping in the same place. The result is that both sides are cut down to the shoulder lines with a “hump” remaining in the middle of the work.
Now to saw the hump, clamp the work in the vertical position and roll the saw horizontal advancing down the hump (see the second picture). The third picture is the result. The tennon is ok. You can see there is some of the line left on one side and nothing on the opposite side. This problem is caused by our bodies. To explain, if you extend your arm away from your body it is easy to roll your palm down. When sawing I have noticed that us right hander’s push the saw plate out as we slightly and inadvertently roll our palms down. This problem shows as the cut travels away from the line or across the line, depending on which side of the tennon I am sawing. I think being aware of this tendency will help correct it. I have done six cuts so I think another 94 and I might actually make something.