Wierd threads part 2
 

I have a bunch of taps I got at auction. marked .120-102

Any one need some? the thread is like fuzz.

IIRC they were from GE in New York.

Any idea what these were for?

Remove 333 to reply.
Randy

Wierd threads part 2
 

"Randy333" wrote in message
...
I have a bunch of taps I got at auction. marked .120-102

Any one need some? the thread is like fuzz.

IIRC they were from GE in New York.

Any idea what these were for?

Remove 333 to reply.
Randy

Fine threads like that are often used for adjusters for optical mounts.
Typically they are an even 100 tpi or 80 tpi. 102 tpi is pretty close to
0.25 mm pitch. Sounds like it is for an adjusting screw with a dial
calibrated in millimeters on a device generally designed in inches.

Wierd threads part 2
 

"anorton" wrote in message
m...

"Randy333" wrote in message
...
I have a bunch of taps I got at auction. marked .120-102

Any one need some? the thread is like fuzz.

IIRC they were from GE in New York.

Any idea what these were for?

Remove 333 to reply.
Randy

Fine threads like that are often used for adjusters for optical mounts.
Typically they are an even 100 tpi or 80 tpi. 102 tpi is pretty close to
0.25 mm pitch. Sounds like it is for an adjusting screw with a dial
calibrated in millimeters on a device generally designed in inches.

Like these:

http://search.newport.com/?q=*&x2=sku&q2=AJS100-0.5


When I used to do work in that area we bought some taps from Newport or
someone for making these threads.

Wierd threads part 2
 

Dennis wrote:
...
http://search.newport.com/?q=*&x2=sku&q2=AJS100-0.5
...

"Sensitivity 0.7 µm"

What does that mean?

Bob

Wierd threads part 2
 

"Bob Engelhardt" wrote in message
...
Dennis wrote:
...
http://search.newport.com/?q=*&x2=sku&q2=AJS100-0.5
...

"Sensitivity 0.7 µm"

What does that mean?

Bob

_____________________________

That means If you are trying to adjust something to a particular position by
looking at an iamge or some other feedback, you are likely to get within 0.7
microns of your target using this screw.

Wierd threads part 2
 

"Bob Engelhardt" wrote in message
...
Dennis wrote:
...
http://search.newport.com/?q=*&x2=sku&q2=AJS100-0.5
...

"Sensitivity 0.7 µm"

What does that mean?

Bob

It's approximately how precisely you can position with it. They are used on
micromanipulators for probing bare integrated circuits and optical bench
lens mounts. The sensitivity limit is the jerky stick-slip travel, which can
be reduced by adjusting the thread tightening collar.
http://www.micromanipulator.com/prod...m=123&cat=124#
The tungsten probe needle is like a tiny TIG electrode.

For a proof-of-concept demo to get a job I've adjusted a 4-jaw lathe chuck
to 1 micron. I used 0-80 lens adjustment threads in the device, though. They
brought me in as the electronics tech and didn't know I could also design
and build delicate mechanical instruments.

0.7um is ~1/4 of a ten-thousandth. Try adjusting a tenth-reading inch
micrometer to a fraction of a vernier division.

jsw

Wierd threads part 2
 

Jim Wilkins wrote:
...
For a proof-of-concept demo to get a job I've adjusted a 4-jaw lathe chuck
to 1 micron. ...

Impressive! What was the tolerance on the piece in the chuck?

Bob

Wierd threads part 2
 

"Bob Engelhardt" wrote in message
...
Jim Wilkins wrote:
...
For a proof-of-concept demo to get a job I've adjusted a 4-jaw lathe
chuck to 1 micron. ...

Impressive! What was the tolerance on the piece in the chuck?

Bob

I only showed that the part could be moved by less than half a division on a
ten-thousandth indicator. The clamping force was too light for machining.

jsw

Wierd threads part 2
 

Jim Wilkins wrote:
...
I only showed that the part could be moved by less than half a division on a
ten-thousandth indicator. ...

Oh, I see. I mis-read your post to mean that you had centered a piece
to less than a micron.

Bob