Eyetalian Threads, ca. 1950
 

There was a thread here about a month ago about restoring an Italian
espresso machine that had metric diameter parts with 'merican thread
pitches.

So I was visiting my sister, and my nephew asks if I can make him a part
for an accordion and hands we a little bent piece of wire that -- shoot
me if I'm wrong -- is threaded with 3mm x 40TPI at the ends.

Cool.

I started talking about this and my sister accused me of not really
belonging in the family seeing as how I'm one of those _restorer_ freaks,
and not the least bit a hot rodder.

So of course then I had to start talking about getting just the right
alloy of 3mm brass stock, and finding a plater, and about how maybe it
would be a crime to fix the damn thing AT ALL because that would mess up
it's provenance.

Fun fun. (the part is made, with 1/8" drill rod and 4-40 threads).

--
http://www.wescottdesign.com

Eyetalian Threads, ca. 1950
 

On Tue, 04 Aug 2009 23:38:38 -0500, Tim Wescott
wrote:

There was a thread here about a month ago about restoring an Italian
espresso machine that had metric diameter parts with 'merican thread
pitches.

So I was visiting my sister, and my nephew asks if I can make him a part
for an accordion and hands we a little bent piece of wire that -- shoot
me if I'm wrong -- is threaded with 3mm x 40TPI at the ends.

Cool.

I started talking about this and my sister accused me of not really
belonging in the family seeing as how I'm one of those _restorer_ freaks,
and not the least bit a hot rodder.

So of course then I had to start talking about getting just the right
alloy of 3mm brass stock, and finding a plater, and about how maybe it
would be a crime to fix the damn thing AT ALL because that would mess up
it's provenance.

Fun fun. (the part is made, with 1/8" drill rod and 4-40 threads).

are the threads 55degree angle or 60 degree angle?

eighth inch whitworth is 40 tpi

Eyetalian Threads, ca. 1950
 

Stealth Pilot wrote:


Fun fun. (the part is made, with 1/8" drill rod and 4-40 threads).

are the threads 55degree angle or 60 degree angle?

eighth inch whitworth is 40 tpi

1/8" British Standard Cycle thread is also 40 tpi, but is 60 degree
rather than Whitworth's 55 deg thread form.

Jordan

Eyetalian Threads, ca. 1950
 

On Wed, 05 Aug 2009 06:43:29 +0000, Stealth Pilot wrote:

On Tue, 04 Aug 2009 23:38:38 -0500, Tim Wescott
wrote:

There was a thread here about a month ago about restoring an Italian
espresso machine that had metric diameter parts with 'merican thread
pitches.

So I was visiting my sister, and my nephew asks if I can make him a part
for an accordion and hands we a little bent piece of wire that -- shoot
me if I'm wrong -- is threaded with 3mm x 40TPI at the ends.

Cool.

I started talking about this and my sister accused me of not really
belonging in the family seeing as how I'm one of those _restorer_
freaks, and not the least bit a hot rodder.

So of course then I had to start talking about getting just the right
alloy of 3mm brass stock, and finding a plater, and about how maybe it
would be a crime to fix the damn thing AT ALL because that would mess up
it's provenance.

Fun fun. (the part is made, with 1/8" drill rod and 4-40 threads).

are the threads 55degree angle or 60 degree angle?

eighth inch whitworth is 40 tpi

They may be 55 degrees, but they sure as heck aren't 1/8" OD -- the shaft
measured too close to 3mm to be anything else, and the OD of the threads
was definitely 3mm, too.

--
http://www.wescottdesign.com

Eyetalian Threads, ca. 1950
 

On Wed, 05 Aug 2009 20:53:04 -0500, Tim Wescott
wrote:


They may be 55 degrees, but they sure as heck aren't 1/8" OD -- the shaft
measured too close to 3mm to be anything else, and the OD of the threads
was definitely 3mm, too.

The limits on the major diameter of a 5-40 UNC-2A thread are
..1242/.1191 -- within .001 of 3mm.

--
Ned Simmons

Eyetalian Threads, ca. 1950
 

On Wed, 05 Aug 2009 22:24:52 -0400, Ned Simmons wrote:

On Wed, 05 Aug 2009 20:53:04 -0500, Tim Wescott
wrote:


They may be 55 degrees, but they sure as heck aren't 1/8" OD -- the
shaft measured too close to 3mm to be anything else, and the OD of the
threads was definitely 3mm, too.

The limits on the major diameter of a 5-40 UNC-2A thread are .1242/.1191
-- within .001 of 3mm.

Hmm. Clearance hole for 5-40 is 1/8, this is definitely smaller than
that.

--
www.wescottdesign.com

Eyetalian Threads, ca. 1950
 

On Thu, 06 Aug 2009 11:15:50 -0500, Tim Wescott
wrote:

On Wed, 05 Aug 2009 22:24:52 -0400, Ned Simmons wrote:

On Wed, 05 Aug 2009 20:53:04 -0500, Tim Wescott
wrote:


They may be 55 degrees, but they sure as heck aren't 1/8" OD -- the
shaft measured too close to 3mm to be anything else, and the OD of the
threads was definitely 3mm, too.

The limits on the major diameter of a 5-40 UNC-2A thread are .1242/.1191
-- within .001 of 3mm.

Hmm. Clearance hole for 5-40 is 1/8, this is definitely smaller than
that.

dont you just hate it when you cant identify a thread. I mean it sits
there bare naked before you, no pretences, and all it fits is the
thread it was mated to. none of the taps and dies of supposedly the
same size come within cooeee of it :-)

"you know love there are just times when it makes more sense to buy a
new one....."

Stealth Pilot

Eyetalian Threads, ca. 1950
 

On Thu, 06 Aug 2009 11:15:50 -0500, Tim Wescott
wrote:

On Wed, 05 Aug 2009 22:24:52 -0400, Ned Simmons wrote:

On Wed, 05 Aug 2009 20:53:04 -0500, Tim Wescott
wrote:


They may be 55 degrees, but they sure as heck aren't 1/8" OD -- the
shaft measured too close to 3mm to be anything else, and the OD of the
threads was definitely 3mm, too.

The limits on the major diameter of a 5-40 UNC-2A thread are .1242/.1191
-- within .001 of 3mm.

Hmm. Clearance hole for 5-40 is 1/8, this is definitely smaller than
that.

just another thought. why not borrow the accordion and run a tap
through the hole that *is* a size you can match parts for.

Stealth Pilot

Eyetalian Threads, ca. 1950
 

On Fri, 07 Aug 2009 00:40:27 +0000, Stealth Pilot wrote:

On Thu, 06 Aug 2009 11:15:50 -0500, Tim Wescott
wrote:

On Wed, 05 Aug 2009 22:24:52 -0400, Ned Simmons wrote:

On Wed, 05 Aug 2009 20:53:04 -0500, Tim Wescott
wrote:


They may be 55 degrees, but they sure as heck aren't 1/8" OD -- the
shaft measured too close to 3mm to be anything else, and the OD of the
threads was definitely 3mm, too.

The limits on the major diameter of a 5-40 UNC-2A thread are
.1242/.1191 -- within .001 of 3mm.

Hmm. Clearance hole for 5-40 is 1/8, this is definitely smaller than
that.

just another thought. why not borrow the accordion and run a tap through
the hole that *is* a size you can match parts for.

Stealth Pilot

That's not an issue -- the piece was broken but good; I had to make an
entirely new one. The replacement uses 1/8" drill rod ('cause I had it)
turned down on the ends and threaded 4-40.

I just thought it was neat to find this interesting bit of historical
trivia sitting in my hand, and even better to be able to use it to pull
my sister's leg a bit.

--
http://www.wescottdesign.com

Eyetalian Threads, ca. 1950
 

On Thu, 06 Aug 2009 11:15:50 -0500, Tim Wescott wrote:
On Wed, 05 Aug 2009 22:24:52 -0400, Ned Simmons wrote:
On Wed, 05 Aug 2009 20:53:04 -0500, Tim Wescott

They may be 55 degrees, but they sure as heck aren't 1/8" OD -- the
shaft measured too close to 3mm to be anything else, and the OD of the
threads was definitely 3mm, too.

The limits on the major diameter of a 5-40 UNC-2A thread are .1242/.1191
-- within .001 of 3mm.

Hmm. Clearance hole for 5-40 is 1/8, this is definitely smaller than
that.

There's a lot of difference between a clearance hole and a tap
drill.

Hope This Helps!
Rich