Struggling with measuring a screw using thread wires.

[macardoso]

yep, same with machinery's handbook calc. you pick wires between the min-max. they do show the optimum.
problem is I don't sync up with that website's calc. not far off, and the bolt I chose, didn't meet spec either...

Fasteners will typically be made in the 1A/B class for a very loose and easy to assemble fit. Machined threads are typically 2A/B unless needed for super precision applications (military, aerospace, instrumentation) in which case they may be 3A/B

 

[woodchucker]

Fasteners will typically be made in the 1A/B class for a very loose and easy to assemble fit. Machined threads are typically 2A/B unless needed for super precision applications (military, aerospace, instrumentation) in which case they may be 3A/B

yea, with that link they are NOT in spec for 1a.
sorry for so many edits... doing 5 things at the moment and screwing all of them up.

 

[RJSakowski]

I posted this a couple of years ago but it bears reposting.

There is a less cumbersome way to measure pitch diameter that is only slightly less accurate. It involves using a single wire. First measure the major diameter of the thread. It doesn't have to be geometrically correct but it should be uniform across the thread. Then insert one wire and measure across the thread and the wire. The "M" value, in the Pee Dee chart and Machinery's Handbook is equal to 2 x the second measurement minus the first measurement.

You still have to go back to the table that is furnished with the pitch wires or to Machinery's Handbook to determine the actual pitch diameter based on the thread pitch, P, the value of M and the diameter of the wire, W.

 

[woodchucker]

yea, I've read about 1 wire.. not that hard doing 3, I had the music wire in 0.041 I knew about the foam... what I didn't know till I cracked the book was that I could use different wire sizes. So that made it eazy peazy???? well almost easy.

 

[Video_man]

If it helps, here's the output from my thread program for class 2 and class 3 threads...

 

[woodchucker]

If it helps, here's the output from my thread program for class 2 and class 3 threads...

thanks, it doesn't help. I only have .041 , so doing the calc in 0.045 does not help.
And it won't help me with validating my excel. The link already provided by 2 others, sought of validates it.. we are close.