reparing 14k v 18k

On Sun, 11 Apr 2004 00:28:42 -0700, in rec.crafts.jewelry Carl West
wrote:

I'm not a machinist and am using my terminology for an inherited tool. I'm
reasonably sure we are using different names for the same tool. Flat plate used
to thread a piece of wire.

There are two basic ways to create threads, cutting and 'rolling' or 'forming'
I think are the terms used. In the former, metal is removed from the shank
either on a screw-cutting lathe or with a thread-cutting die. In the latter,
the thread grooves are pressed in to the shank, the extra metal becomes the
high part of the thread. I was wondering if the 'threading plate' might be the
latter. The test: do 'shavings' come off when you use it?

Normal machinist style taps and dies use seperate threading dies for each
threat. A traditional style of threading die used by jewelers and watchmakers
employs a single piece of steel plate, with multiple dies formed into it. They
are available in a variety of qualities. Here are a couple sets sold by
Contenti. one is german, high quality, and costs $136.00. The second is a
similar, but lower quality tool from india, for twenty bucks.

http://www.contenti.com/products/drills/200-305.html
http://www.contenti.com/products/drills/200-302.html

Peter

How do you assure that the head is concentric and square with the shank?

Two ways. You can either leave the shank of the screw extra long and put it
in a third hand with the head resting on your soldering block(if its a flat
head), or leave the diameter of the head large enough to take it down with a
file after soldering. The second would probably work better if you needed a
rounded head.

I was wondering if the 'threading plate' might be the
latter. The test: do 'shavings' come off when you use it?

See Peters post. You just screw the wire down into the hole that
corresponds to the threads you want. Personally, I find that to be the hardest
part of the whole job. Picking the right hole.

NE333RO wrote:

How do you assure that the head is concentric and square with the shank?

Two ways. You can either leave the shank of the screw extra long and put it
in a third hand with the head resting on your soldering block(if its a flat
head), or leave the diameter of the head large enough to take it down with a
file after soldering. The second would probably work better if you needed a
rounded head.

Ah. By eye.


... Personally, I find that to be the hardest
part of the whole job. Picking the right hole.

That applies to so much of life...

Either you find a tap that fits the existing hole or a die that fits an
existing screw, that tells you the size. Then you need a wire that's just a
hair smaller than the tap for that size. or drill a hole somewhat smaller than
that.

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"Clutter"? This is an object-rich environment.

Ah. By eye.

I've yet to have one where that wasn't sufficient. You can do a perfectly
credible job by eye. The precision needed to make a balance staff or stem is
not needed.

Either you find a tap that fits the existing hole or a die that fits an
existing screw, that tells you the size. Then you need a wire that's just a
hair smaller than the tap for that size. or drill a hole somewhat smaller
than
that.

I'd be REAL careful running a hardened steel tap down a threaded gold hole.
Same with running a gold screw down a hardened steel thread plate. I usually
thread a small piece of scrap gf wire until I get the right size.

NE333RO wrote:

Ah. By eye.

I've yet to have one where that wasn't sufficient. You can do a perfectly
credible job by eye. The precision needed to make a balance staff or stem is
not needed.

Maybe I'm getting hung-up in "supposed to be". I'm used to screws being
machined items from head to tip.


Either you find a tap that fits the existing hole or a die that fits an
existing screw, that tells you the size. Then you need a wire that's just a
hair smaller than the tap for that size. or drill a hole somewhat smaller
than
that.

I'd be REAL careful running a hardened steel tap down a threaded gold hole.
Same with running a gold screw down a hardened steel thread plate. I usually
thread a small piece of scrap gf wire until I get the right size.

A fine plan. Do you count that into the ten minutes to make the screw?

I guess there'd be value in making a brass or silver testing plate for trying
screws in too.

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"Clutter"? This is an object-rich environment.

A fine plan. Do you count that into the ten minutes to make the screw?

Ok, maybe 11 minutes )

I guess there'd be value in making a brass or silver testing plate for trying
screws in too.

I wouldn't bother. Most screws a jeweler deals with are within the same
general three or four sizes. Like you said earlier you won't do THAT many of
them. If I don't have a piece of gf laying around I usually just thread the
gold wire the size I think it should be (by comparing to the hole its going in)
and if that doesnt fit, take it down to the next die. More chance of breaking
your wire, but I usually hit it the first or second time.