I have not actually dropped off the face of the earth,
rather I've been busy screwing things up in the shop.
Recall those big screws I was cutting by hand?
2-1/2 inch 2-tpi they are, more or less.
I finished the cherry screw, then turned and carved a
second one from walnut. They looked okay, so I
began the next task, to build the tapping jig.
This is based on S24 Ep6 of the Woodwright's shop
where Roy cuts some threads. I found out that his
thread cutter is equivalent to what Heron of Alexandria
described in the 1st Century AD. I am standing on the
shoulders of giants, indeed.
This should be the 'false nut' that guides the tapping jig.
If the picture links don't work, I'll also give the album
link at the end.
Here is the cutter. It's a scraper, filed and honed from a
scrap of annealed O1. I don't think I'll bother hardening
it because I don't plan on tapping a lot of holes.
The cutter is held in place by a wedge.
I set the tapping jig up on a vise so I could access and
work it easily. In operation, you set the cutter with a
punch, like 1/64th of an inch or so, and run it through
the blank. The root diameter hole was bored at 1-3/4 inch.
The dross is knocked off at the other end, then you run it
through again. Repeat this procedure for an eternity.
This is the partially formed internal thread.
Eventually you end up with this:
Beautiful, isn't it?
Then I endured another tedious round of paring threads.
Of course my hamfisted attempts to cut a screw by
hand and eye left a little to be desired. But eventually
(You keep saying that word. I do not think it means
what you think it means) the nut fits and spins down
the screw quite nicely. Too bad I can't load videos here.
Here's the album the pictures live in.
Or go searching for "Darrell's Photogs"
So, now it's on to the second screw (the cherry one).
Once I have that fettled to fit the test nut I will have to
start making jaws.
I am altogether far too pleased with myself right now.
What was it Scrooge said?
"I am as merry as a schoolboy. I am as giddy as a drunken man."
Wood Hoarder, Blade Sharpener, and Occasional Tool User