Not metal but Ivory and ivory substitutes i.e. plastics.
Repairing an older set of bagpipes, noted the ivory ferrules were threaded
on the wood sections (African blackwood) with a 24 tpi thread, not parallel
but tapered. These threads were probably cut on a (wood)lathe using a hand
chaser. That is an art that I do not have, but I do have a metal lathe with
screwcutting capability but no taper attachment.
So how can I turn a tapered thread?
The wooden sections are 10 inches long, so possibly between centres with the
tailstock offset. The ferrules are 1 inch long with internal thread ??
Bushings are 1/4 inch thick with external thread.
Would prefer to stay with tapered thread as these are usually restorations.
Any ideas?
Ray

honestly, the simplest thing to do would be to learn hand chasing - if you
cut the beginnings of the thread (even ignoring taper) on your metal lathe
you will make it easier
"Ray Field" wrote in message
news:4j5Di.12226$Pd4.11673@edtnps82...
Not metal but Ivory and ivory substitutes i.e. plastics.
Repairing an older set of bagpipes, noted the ivory ferrules were threaded
on the wood sections (African blackwood) with a 24 tpi thread, not
parallel but tapered. These threads were probably cut on a (wood)lathe
using a hand chaser. That is an art that I do not have, but I do have a
metal lathe with screwcutting capability but no taper attachment.
So how can I turn a tapered thread?
The wooden sections are 10 inches long, so possibly between centres with
the tailstock offset. The ferrules are 1 inch long with internal thread ??
Bushings are 1/4 inch thick with external thread.
Would prefer to stay with tapered thread as these are usually
restorations.
Any ideas?
Ray




--
Posted via a free Usenet account from http://www.teranews.com

"Ray Field" wrote:

Not metal but Ivory and ivory substitutes i.e. plastics.... 24 tpi thread, not parallel
but tapered. These threads were probably cut on a (wood)lathe using a hand
chaser. That is an art that I do not have, but I do have a metal lathe with
screwcutting capability but no taper attachment.
So how can I turn a tapered thread?
Ray

If you want workable rather than beautiful threads, cut the taper in
steps. You could make a spreadsheet that calculates where to end each
successive pass for perhaps 0.001 depth of cut, then clean up a little
with a thread-restoring file or the side of a tap. Put the actual
infeed value in a cell as a constant so you can easily change it.

I've made 3" cast-iron ball joints this way, stepping X and Y from a
spreadsheet and filing out the tool marks.

As another discussion pointed out, this is easier to do on an old
leather-belt-driven lathe which can be turned by hand to an exact dial
indicator reading.

jw

In article 4j5Di.12226$Pd4.11673@edtnps82,
"Ray Field" wrote:

Not metal but Ivory and ivory substitutes i.e. plastics.
Repairing an older set of bagpipes, noted the ivory ferrules were threaded
on the wood sections (African blackwood) with a 24 tpi thread, not parallel
but tapered. These threads were probably cut on a (wood)lathe using a hand
chaser. That is an art that I do not have, but I do have a metal lathe with
screwcutting capability but no taper attachment.
So how can I turn a tapered thread?
The wooden sections are 10 inches long, so possibly between centres with the
tailstock offset. The ferrules are 1 inch long with internal thread ??
Bushings are 1/4 inch thick with external thread.
Would prefer to stay with tapered thread as these are usually restorations.
Any ideas?
Ray

Make a steel tap using offset, make a die from the tap

Free men own guns - www(dot)geocities(dot)com/CapitolHill/5357/

On Tue, 04 Sep 2007 04:38:24 GMT, Ray Field wrote:

Not metal but Ivory and ivory substitutes i.e. plastics.
Repairing an older set of bagpipes, noted the ivory ferrules were threaded
on the wood sections (African blackwood) with a 24 tpi thread, not parallel
but tapered. These threads were probably cut on a (wood)lathe using a hand
chaser. That is an art that I do not have, but I do have a metal lathe with
screwcutting capability but no taper attachment.
So how can I turn a tapered thread?
The wooden sections are 10 inches long, so possibly between centres with the
tailstock offset. The ferrules are 1 inch long with internal thread ??
Bushings are 1/4 inch thick with external thread.
Would prefer to stay with tapered thread as these are usually restorations.
Any ideas?
Ray

It sort of depends on what you actually mean by "tapered threads".

If the thread is the same depth all the way and the id of the threaded
portion is a taper, that's one possibility. If the id remains the same,
and the thread depth decreases, that's another. I suppose there's another,
the combination of the two, but nevermind - if the material is soft and the
threaded portion is short, why can't you just set the compound to the
correct angle, and cut 'em? Set the tool at 90 degrees, and make passes
increasing the depth of cut with the cross slide.

On Tue, 04 Sep 2007 05:54:11 -0500, nick hull wrote:

In article 4j5Di.12226$Pd4.11673@edtnps82,
"Ray Field" wrote:

Not metal but Ivory and ivory substitutes i.e. plastics.
Repairing an older set of bagpipes, noted the ivory ferrules were threaded
on the wood sections (African blackwood) with a 24 tpi thread, not parallel
but tapered. These threads were probably cut on a (wood)lathe using a hand
chaser. That is an art that I do not have, but I do have a metal lathe with
screwcutting capability but no taper attachment.
So how can I turn a tapered thread?
The wooden sections are 10 inches long, so possibly between centres with the
tailstock offset. The ferrules are 1 inch long with internal thread ??
Bushings are 1/4 inch thick with external thread.
Would prefer to stay with tapered thread as these are usually restorations.
Any ideas?
Ray

Make a steel tap using offset, make a die from the tap
fe]]ubt
Free men own guns - www(dot)geocities(dot)com/CapitolHill/5357/

If your lathe has the capability of offsetting the tail stock you can
easily cut a tapered thread. Turn between centers and offset the tail
stock. It is just like making a straight thread.


Bruce in Bangkok
(brucepaigeATgmailDOTcom)

On Sep 4, 12:38 am, "Ray Field" wrote:
Not metal but Ivory and ivory substitutes i.e. plastics.
Repairing an older set of bagpipes, noted the ivory ferrules were threaded
on the wood sections (African blackwood) with a 24 tpi thread, not parallel
but tapered. These threads were probably cut on a (wood)lathe using a hand
chaser. That is an art that I do not have, but I do have a metal lathe with
screwcutting capability but no taper attachment.
So how can I turn a tapered thread?
The wooden sections are 10 inches long, so possibly between centres with the
tailstock offset. The ferrules are 1 inch long with internal thread ??
Bushings are 1/4 inch thick with external thread.
Would prefer to stay with tapered thread as these are usually restorations.
Any ideas?
Ray

External threads are easily done by offsetting the tailstock.

For the internally threaded ferrules, you could turn a taper thread by
mounting them on a longer shaft and then running that between the
headstock center and an offset steady rest. Hold the shaft on to the
center by lashing with rawhide or something similar.

A taper attachment would be easier.

John Martin

"William Noble" wrote:

honestly, the simplest thing to do would be to learn hand chasing - if you
cut the beginnings of the thread (even ignoring taper) on your metal lathe
you will make it easier


Ah, took a moment to figure out what you may mean. Straight cut gives guide
lines. Increasing / decreasing pressure using a hand single V tool
depending on which way OP is going.

Wes

On Sep 4, 3:15 pm, Wes wrote:
....
Ah, took a moment to figure out what you may mean. Straight cut gives guide
lines. Increasing / decreasing pressure using a hand single V tool
depending on which way OP is going.
Wes

You could make a multiple thread chasing tool from a broken 5/16- or
3/8-24 tap.

jw