Clock reset assembly standard dash

[elan71]

Hi
I'm trying the reproduce the clock reset assembly for a standard dash for a 70-71 e-Body.
With the help of this forum, I got all the correct measurement. A friend helped me with the first prototype.
It came out very good as you can see on the picture. I'm struggling with the small thread on the small pin.
Can anybody find out what kind of thread this is? I thought it is a 1-72 UNF? But I have no idea is this correct or not. 
The reset knob on the rally dash have the same size there.
As I'm in Switzerland, I don't have the tools here to check the correct thread.
I hope anybody can help me.
Thank you in advance.
Daniel

[SgtSuperbird]

I can't help you, but very nice work!

[gzig5]

I have the large outer sleeve in my dash but am missing the knob and inner shaft.  I assume the thread goes into the smaller sleeve shown which acts as a nut in order to hold the shaft in the knob, and thus the knob in the outer sleeve?

Do you have a micrometor or caliper to measure thread diameter?  Using some magnification, you can count the number of threads over .250" length and multiply x4 to get the approximate TPI.  You may try taking it to a clock or watch repair shop and they may have the proper thread pitch gages.  I don't think that Switzerland has always been a metric country, until the late 1870's. 

[elan71]

Ok, I got a TPI of 40. What is TPI?
The caliper shows me 2mm which is 0.0787" I beleve.

Well, since I'm on the earth, we have meters

[gzig5]

Ok, I got a TPI of 40. What is TPI?
The caliper shows me 2mm which is 0.0787" I beleve.

Well, since I'm on the earth, we have meters

TPI means "threads per inch" .  40 TPI is equivalent to 0.64mm pitch
I was going to guess 4-40 size but the examples I have measure 0.110" diameter. 

The diameter you give is similar to a 1-64 but the thread pitch if correct, doesn't match. It could be a custom dimension.
This chart gives some dimensions of the standard screw threads.  http://www.carbidedepot.com/formulas-tap-standard.htm

[anlauto]

TPI = Threads per inch

Dam 0.08 too late 

[Skdmark]

1-64UNC and 1-72UNF have the same major diameter.
72 TPI = pitch of 0.01389in or 0.352mm (spacing between center of the thread crests)

I believe the threads are also the same on Rallye gauges too. If you can wait until Saturday I can check mine.

[elan71]

Thank you for all the answers. I learn every day something more. Cool.
Everything is very small, difficult to count the thread crests...
@Skdmark Yes, Ralley gauges have the same thread there. I'm not under pressure, waiting some days is absolutely no problem.
Looking forward to find the solution here.
Thank you all again!!

[elan71]

@Skdmark  have you found the time to check it on your car? Would be great.
Thank you in advance
Daniel

[Skdmark]

@elan71
I took the nut from the rest knob to the hardware store to confirm the size on Sunday. Unfortunately they only went down to 4-40 / 4-48 with their inventory. I plan on making a trip to a hobby store this week and I will try there as they carry hardware for model railroaders. At this point it's just confirming the pitch of 72 TPI vs 64 TPI. My thread pitch gauge only goes down to 48 TPI as well.

I'm fairly confident it is 1-72 UNF just need to get a final confirmation for you.

[elan71]

@Skdmark ,
Sounds great!
1-72UNF was my tough too, but I'm not sure.
Thank you for your help!

[Skdmark]

@elan71
Made a trip to the hobby store and picked up some 1-72 UNF brass nuts.
They thread right onto my original rallye speedometer trip meter.

When I tried them on the reproduction reset cable for the rallye clock they were a bit tight.
I'm thinking the lead threads on the repro cable have a burr on them from when the flats are machined on the threaded portion.

So the thread on the stem should be a 1-72UNF

[elan71]

@Skdmark     Thank you very much for the additional effort, support and confirmation.!! 
This is very helpful and I can make the correct thread on the reproduction.

I keep you all infomred about the process.

Thank you all for the support again.

Daniel

[elan71]

Now I got around to installing the prototype.
Unlike other photos I have found here, the unit disappears almost completely in the dashboard. Only the button looks out.
This is actually quite good, especially if you have a radio installed. The button disturbs so much less. The function is perfect.
I followed the measurements here from the forum.
My question now, is this factory correct? How was it from the factory?
Are there other examples I may see?
I want to be sure it is as it was from the factory.

Daniel

[Rdchallenger]

Now I got around to installing the prototype.
Unlike other photos I have found here, the unit disappears almost completely in the dashboard. Only the button looks out.
This is actually quite good, especially if you have a radio installed. The button disturbs so much less. The function is perfect.
I followed the measurements here from the forum.
My question now, is this factory correct? How was it from the factory?
Are there other examples I may see?
I want to be sure it is as it was from the factory.

Daniel

Who cares if it's correct! It's awesome and fills that dead gauge nicely. I may have to get one.