Making Threads, was RE: [TheForge] Re: Vice repair

[Jeffrey Polaski]

On the subject of making threads, I just made two sets of square threads
for 3/4" pipe. They are going to join ramable refractory burner nozzles
to the pipe, so they are not real precise or high-strength or anything.
They just need to stand up to the high temperature and allow me to swap
out a nozzle occasionally.

This is how I did it:

1.) Take two pieces of 1/8" square stock (about 18" long) and weld the
ends together, along with spot welds every inch or so along the top. You
can do it without the spot welds, but the threads will match up much
better if you do. 

2.) Heat it up and wrap it around a piece of pipe, keeping the edges
next to each other as it wraps around the pipe.

3.) Cut the welds and unscrew to get two separate sets of "threads" 

4.) Weld the "threads" onto a piece of the same size pipe.

I don't know it the explanation make a lot of sense, but it's pretty
easy one you start. I read about it in an old Anvil's Ring, where the
same technique was used to make threading taps for woodworkers.




-----Original Message-----
From: theforge-bounces at mailman.qth.net
[mailto:theforge-bounces at mailman.qth.net] On Behalf Of Mike Spencer
Sent: Monday, August 22, 2005 11:32 PM
To: theforge at mailman.qth.net
Subject: [TheForge] Re: Vice repair


> ... a really close look at the thread box and discovered that it was
> just a piece of steel pipe that had been swaged around the screw.

You mean that it's just a piece of pipe, like, rudely mashed into the
male threads?  Yow.  That's a new one for me.

> ...I heated it up and repeated the process using a half round
> section on the block that was the closest fit.  Well it seemed to
> have worked.  The threads are tight again and seem to work just
> fine.

Amazing.

Recently I made a square-threaded tube for a woodworker's vise.  Filed
some
1/8" sq. to a kind of / \ cross section, hot-wrapped it on the male
thread
narrow edge in (to allow for the swelling on the inside of a bend).

Hammered it lightly all over and wound it off, slipped the little
pig-tail-like thread into a piece of pipe and brazed it in place.  Had
to grind out one blob of excess brass with a dental drill.  Then
lapped the male thread into it with abrasive paste.  Seems to be fine.

I got this idea from Dimitri Gerakaris year ago.  He did it with a leg
vise.  He later reported that it hadn't stood up to heavy use but I
don't recall that he elaborated on just how heavy the use was.

Let us know how your fix works out after a month or three.


- Mike
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