What would be my best bet for getting a relatively small quantity
(current requirement is 100 pieces) of machine screws (a couple of
sizes, like 6-32) made from 0.25" dia. metal rod. The material (Nb) is
soft like copper and generally nasty to machine. I'd like a Torx or
similar head so it's not as easy to screw up as a slot.

Ideas? Real screw-making machines - heading and thread forming- look
like a bit much for the purpose (thousands of pounds and many HP).

On Mon, 17 Aug 2009 12:17:03 -0400, Spehro Pefhany wrote:

What would be my best bet for getting a relatively small quantity
(current requirement is 100 pieces) of machine screws (a couple of
sizes, like 6-32) made from 0.25" dia. metal rod. The material (Nb) is
soft like copper and generally nasty to machine. I'd like a Torx or
similar head so it's not as easy to screw up as a slot.

Ideas? Real screw-making machines - heading and thread forming- look
like a bit much for the purpose (thousands of pounds and many HP).

AFAIK, anything but a slot means a forming or broaching operation, and
may push you into a screw machine.

Other than that, for 100ea it could probably be done on an NC lathe by
any competent prototype/small-run machine shop, if they were willing to
mess with the material. For a genuine 100, with soft material, you may
be able to form the top with a hand-made die and a mallet, but you'd
probably spend a lot of time dinking with the process before it worked.

Off the wall -- could they be cast with a simple die, as nylon screws are?

Why are you having screws made from depleted uranium, anyway? (:-)

--
www.wescottdesign.com

On Mon, 17 Aug 2009 11:21:32 -0500, Tim Wescott
wrote:

On Mon, 17 Aug 2009 12:17:03 -0400, Spehro Pefhany wrote:

What would be my best bet for getting a relatively small quantity
(current requirement is 100 pieces) of machine screws (a couple of
sizes, like 6-32) made from 0.25" dia. metal rod. The material (Nb) is
soft like copper and generally nasty to machine. I'd like a Torx or
similar head so it's not as easy to screw up as a slot.

Ideas? Real screw-making machines - heading and thread forming- look
like a bit much for the purpose (thousands of pounds and many HP).

AFAIK, anything but a slot means a forming or broaching operation, and
may push you into a screw machine.

EDM might be another possibility, but it would be expensive, of
course.

Other than that, for 100ea it could probably be done on an NC lathe by
any competent prototype/small-run machine shop, if they were willing to
mess with the material. For a genuine 100, with soft material, you may
be able to form the top with a hand-made die and a mallet, but you'd
probably spend a lot of time dinking with the process before it worked.

Off the wall -- could they be cast with a simple die, as nylon screws are?

Don't think so, the stuff melts at quite a high temperature.

Why are you having screws made from depleted uranium, anyway? (:-)

It has to be a superconductor, and reasonably closely matched CTE to
other "stuff" in the physics package. ;-)

On Aug 17, 9:17*am, Spehro Pefhany
wrote:
What would be my best bet for getting a relatively small quantity
(current requirement is 100 pieces) of machine screws (a couple of
sizes, like 6-32) made from 0.25" dia. metal rod. The material (Nb) is
soft like copper and generally nasty to machine. I'd like a Torx or
similar head so it's not as easy to screw up as a slot.

Ideas? Real screw-making machines - heading and thread forming- look
like a bit much for the purpose (thousands of pounds and many HP). *

Main idea: convert to rivets.

Lesser ideas: heads of the 12-point style are easily driven and
formed, might
give better strength than an internal socket. You can probably roll
threads
easily enough, the first size down from 0.25" rod is 1/4-28.

The table says yield strength is closer to stainless than to copper.

On Mon, 17 Aug 2009 13:47:49 -0400, Spehro Pefhany
wrote:

On Mon, 17 Aug 2009 11:21:32 -0500, Tim Wescott
wrote:

On Mon, 17 Aug 2009 12:17:03 -0400, Spehro Pefhany wrote:

What would be my best bet for getting a relatively small quantity
(current requirement is 100 pieces) of machine screws (a couple of
sizes, like 6-32) made from 0.25" dia. metal rod. The material (Nb) is
soft like copper and generally nasty to machine. I'd like a Torx or
similar head so it's not as easy to screw up as a slot.



Assuming that it's sufficiently unpleasant to machine. If you can manage to
find a way to cold form the heads, then roll forming the threads would be
relatively simple.

Mark Rand
RTFM

On Aug 17, 12:17*pm, Spehro Pefhany
wrote:
What would be my best bet for getting a relatively small quantity
(current requirement is 100 pieces) of machine screws (a couple of
sizes, like 6-32) made from 0.25" dia. metal rod. The material (Nb) is
soft like copper and generally nasty to machine. I'd like a Torx or
similar head so it's not as easy to screw up as a slot.

Ideas? Real screw-making machines - heading and thread forming- look
like a bit much for the purpose (thousands of pounds and many HP). *

Possible change in design: a threaded rod, a washer and a nut on top.

On Mon, 17 Aug 2009 15:17:03 -0700 (PDT), the renowned brakadabras
wrote:

On Aug 17, 12:17*pm, Spehro Pefhany
wrote:
What would be my best bet for getting a relatively small quantity
(current requirement is 100 pieces) of machine screws (a couple of
sizes, like 6-32) made from 0.25" dia. metal rod. The material (Nb) is
soft like copper and generally nasty to machine. I'd like a Torx or
similar head so it's not as easy to screw up as a slot.

Ideas? Real screw-making machines - heading and thread forming- look
like a bit much for the purpose (thousands of pounds and many HP). *

Possible change in design: a threaded rod, a washer and a nut on top.

Great, now I have to figure out how to make/get made special Nb nuts
and Nb washers, as well as Nb threaded rod.

;-) ;-)


Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com

On Mon, 17 Aug 2009 23:09:52 +0100, the renowned Mark Rand
wrote:

On Mon, 17 Aug 2009 13:47:49 -0400, Spehro Pefhany
wrote:

On Mon, 17 Aug 2009 11:21:32 -0500, Tim Wescott
wrote:

On Mon, 17 Aug 2009 12:17:03 -0400, Spehro Pefhany wrote:

What would be my best bet for getting a relatively small quantity
(current requirement is 100 pieces) of machine screws (a couple of
sizes, like 6-32) made from 0.25" dia. metal rod. The material (Nb) is
soft like copper and generally nasty to machine. I'd like a Torx or
similar head so it's not as easy to screw up as a slot.



Assuming that it's sufficiently unpleasant to machine. If you can manage to
find a way to cold form the heads, then roll forming the threads would be
relatively simple.

Mark Rand
RTFM

Thanks, Mark. That definitely sounds like a possibility. I see tooling
available for CNC thread rolling and rotary broaching of the hex/Torx.


Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com

On Mon, 17 Aug 2009 15:07:49 -0700 (PDT), the renowned whit3rd
wrote:

On Aug 17, 9:17*am, Spehro Pefhany
wrote:
What would be my best bet for getting a relatively small quantity
(current requirement is 100 pieces) of machine screws (a couple of
sizes, like 6-32) made from 0.25" dia. metal rod. The material (Nb) is
soft like copper and generally nasty to machine. I'd like a Torx or
similar head so it's not as easy to screw up as a slot.

Ideas? Real screw-making machines - heading and thread forming- look
like a bit much for the purpose (thousands of pounds and many HP). *

Main idea: convert to rivets.

Lesser ideas: heads of the 12-point style are easily driven and
formed, might
give better strength than an internal socket.

Have a design problem where the driver (but not the head) has to fit
through a relatively small hole in some cases (imagine putting the
screw into the internal side wall of a pocket, driven through a
smallish access hole), but it's certainly worth considering. Maybe a
two piece driver.

You can probably roll
threads
easily enough, the first size down from 0.25" rod is 1/4-28.

The table says yield strength is closer to stainless than to copper.

I'm told this stuff is very, very pure and annealed, and is softer and
gummier than copper. I see yields in the mid-fifties MPa on the net.
I'll try to get a chunk of rod and actually play with it.


Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com

On Aug 17, 6:17*am, Spehro Pefhany
wrote:
What would be my best bet for getting a relatively small quantity
(current requirement is 100 pieces) of machine screws (a couple of
sizes, like 6-32) made from 0.25" dia. metal rod. The material (Nb) is
soft like copper and generally nasty to machine. I'd like a Torx or
similar head so it's not as easy to screw up as a slot.

Ideas? Real screw-making machines - heading and thread forming- look
like a bit much for the purpose (thousands of pounds and many HP). *

Is this for jewelry? Niobium jewelry is becoming popular. I'd check
the finding suppliers to see if there's anything being made you can
use.
Karl

On Tue, 18 Aug 2009 04:22:33 -0700 (PDT), kfvorwerk
wrote:

On Aug 17, 6:17*am, Spehro Pefhany
wrote:
What would be my best bet for getting a relatively small quantity
(current requirement is 100 pieces) of machine screws (a couple of
sizes, like 6-32) made from 0.25" dia. metal rod. The material (Nb) is
soft like copper and generally nasty to machine. I'd like a Torx or
similar head so it's not as easy to screw up as a slot.

Ideas? Real screw-making machines - heading and thread forming- look
like a bit much for the purpose (thousands of pounds and many HP). *

Is this for jewelry?

Only indirectly. Among other things, it helps find certain kinds of
very hard glittery objects under the ground that typically get made
into jewellery.

Niobium jewelry is becoming popular. I'd check
the finding suppliers to see if there's anything being made you can
use.
Karl

Thanks, Karl, I've asked for a piece of the real stuff. They say the
really pure annealed stuff is gummy, soft *and* abrasive and requires
large rake angles to turn.

With the right tooling it should be feasible to do this on a CNC
lathe, but I think it might cost a couple thousand for the tools (not
a problem, if it works).

In article ,
Spehro Pefhany wrote:

On Tue, 18 Aug 2009 04:22:33 -0700 (PDT), kfvorwerk
wrote:

On Aug 17, 6:17*am, Spehro Pefhany
wrote:
What would be my best bet for getting a relatively small quantity
(current requirement is 100 pieces) of machine screws (a couple of
sizes, like 6-32) made from 0.25" dia. metal rod. The material (Nb) is
soft like copper and generally nasty to machine. I'd like a Torx or
similar head so it's not as easy to screw up as a slot.

Ideas? Real screw-making machines - heading and thread forming- look
like a bit much for the purpose (thousands of pounds and many HP). *

Is this for jewelry?

Only indirectly. Among other things, it helps find certain kinds of
very hard glittery objects under the ground that typically get made
into jewellery.

Niobium jewelry is becoming popular. I'd check
the finding suppliers to see if there's anything being made you can
use.
Karl

Thanks, Karl, I've asked for a piece of the real stuff. They say the
really pure annealed stuff is gummy, soft *and* abrasive and requires
large rake angles to turn.

With the right tooling it should be feasible to do this on a CNC
lathe, but I think it might cost a couple thousand for the tools (not
a problem, if it works).

Does it need to be solid niobium? I've been reading articles from CERN
about their success in using niobium plated components in accelerators.

Joe Gwinn

On Tue, 18 Aug 2009 22:38:37 -0400, the renowned Joseph Gwinn
wrote:

In article ,
Spehro Pefhany wrote:

On Tue, 18 Aug 2009 04:22:33 -0700 (PDT), kfvorwerk
wrote:

On Aug 17, 6:17*am, Spehro Pefhany
wrote:
What would be my best bet for getting a relatively small quantity
(current requirement is 100 pieces) of machine screws (a couple of
sizes, like 6-32) made from 0.25" dia. metal rod. The material (Nb) is
soft like copper and generally nasty to machine. I'd like a Torx or
similar head so it's not as easy to screw up as a slot.

Ideas? Real screw-making machines - heading and thread forming- look
like a bit much for the purpose (thousands of pounds and many HP). *

Is this for jewelry?

Only indirectly. Among other things, it helps find certain kinds of
very hard glittery objects under the ground that typically get made
into jewellery.

Niobium jewelry is becoming popular. I'd check
the finding suppliers to see if there's anything being made you can
use.
Karl

Thanks, Karl, I've asked for a piece of the real stuff. They say the
really pure annealed stuff is gummy, soft *and* abrasive and requires
large rake angles to turn.

With the right tooling it should be feasible to do this on a CNC
lathe, but I think it might cost a couple thousand for the tools (not
a problem, if it works).

Does it need to be solid niobium? I've been reading articles from CERN
about their success in using niobium plated components in accelerators.

Joe Gwinn

Hi, Joe--

You're right, it probably doesn't have to be from a superconducting
pov, but there's some worry about the CTE match with almost 300°C
temperature swings-- could make it fail or work loose.


Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com

In article ,
Spehro Pefhany wrote:

On Tue, 18 Aug 2009 22:38:37 -0400, the renowned Joseph Gwinn
wrote:

In article ,
Spehro Pefhany wrote:

On Tue, 18 Aug 2009 04:22:33 -0700 (PDT), kfvorwerk
wrote:

On Aug 17, 6:17*am, Spehro Pefhany
wrote:
What would be my best bet for getting a relatively small quantity
(current requirement is 100 pieces) of machine screws (a couple of
sizes, like 6-32) made from 0.25" dia. metal rod. The material (Nb) is
soft like copper and generally nasty to machine. I'd like a Torx or
similar head so it's not as easy to screw up as a slot.

Ideas? Real screw-making machines - heading and thread forming- look
like a bit much for the purpose (thousands of pounds and many HP). *

Is this for jewelry?

Only indirectly. Among other things, it helps find certain kinds of
very hard glittery objects under the ground that typically get made
into jewellery.

Niobium jewelry is becoming popular. I'd check
the finding suppliers to see if there's anything being made you can
use.
Karl

Thanks, Karl, I've asked for a piece of the real stuff. They say the
really pure annealed stuff is gummy, soft *and* abrasive and requires
large rake angles to turn.

With the right tooling it should be feasible to do this on a CNC
lathe, but I think it might cost a couple thousand for the tools (not
a problem, if it works).

Does it need to be solid niobium? I've been reading articles from CERN
about their success in using niobium plated components in accelerators.

Joe Gwinn

Hi, Joe--

You're right, it probably doesn't have to be from a superconducting
pov, but there's some worry about the CTE match with almost 300°C
temperature swings-- could make it fail or work loose.

I'd google around the CERN website. They have to have dealt with this
issue too. I'm guessing that the base metal upon which the niobium is
plated has about the same CTE, if only so the plating doesn't peel off.

CERN did it for the money - the base metal was far easier to fabricate
than niobium, and plating saved on material costs as well.

Joe Gwinn

On Aug 18, 5:15*am, Spehro Pefhany
wrote:
On Mon, 17 Aug 2009 15:07:49 -0700 (PDT), the renowned whit3rd





wrote:
On Aug 17, 9:17*am, Spehro Pefhany
wrote:
What would be my best bet for getting a relatively small quantity
(current requirement is 100 pieces) of machine screws (a couple of
sizes, like 6-32) made from 0.25" dia. metal rod. The material (Nb) is
soft like copper and generally nasty to machine. I'd like a Torx or
similar head so it's not as easy to screw up as a slot.

Ideas?...

Have a design problem where the driver (but not the head) has to fit
through a relatively small hole in some cases (imagine putting the
screw into the internal side wall of a pocket, driven through a
smallish access hole), but it's certainly worth considering. Maybe a
two piece driver.

Try milling two crossed slots and then pounding a Phillips bit into
the center to swage out a Phillips recess.

jsw