I knew I had a label for it. Screw chasing, that's what it was. Took forever to find it though. So today's post returns us to March and April of last year. When summer comes I move outdoors so nothing got done since then. Well, I watched lot of thread-chasing videos on YouTube and I must say I admire the dexterity of these people, not to mention the fact that they put their knowledge out on the net for all to see. Generous to a fault. Anyway, you will recall that this label deals with cutting threads in wood. The methods range from ancient Greek techniques (cut thread with chisel) to wood taps and dies and finally chasing on a lathe. Since I want to use my Polecat this is not a trivial undertaking.
Tape the paper down to your cylinder really well. else it will slip and make hash out of your efforts. Now, just like the Greeks, take your mini-dozuki saw and saw out the lines, rotating the lathe by hand. Do not try to treadle.
When you get the groove deep enough you will find you can actually treadle; the tool will follow the groove all by itself. Not only that, the multi-tooth chase actually works! See previous posts. But you must treadle very slowly. This is hard to do. The temptation to bash the treadle down is overwhelming. Resist it. Any machinist knows that to cut a thread you put the lathe in backgear and take the slowest speed you have. I have no backgear, it's all my leg. It is all too easy to have the tool jump out of the groove, or dig in.
The above shots were staged for the blog. When I was working this out I had no thoughts of taking pictures. But at the end of the day I had cut a quite respectable thread on the left end of the turning.
And at last we have snow on the ground. Not much, about 2cm. Enough to ski on! I was so tired of walking.
Malone vs Berenson
2 days ago