Lachenal And Wheatstone Thumbscrew Threads

[RWL]

I got a 3-48 die and made some thumbscrews for my Edeophone. I'll have to wait for the 6 BA die to make somewhat larger screws for my Wheatstone model 21. Photos of the project completion below.

 

[Despite uploading the photos in the correct order, they appear out of order in the post and I don't know how to correct that.]

Edited August 7, 2015 by RWL

[Dana Johnson]

Very nice looking!

Dana

[Discord]

A bit late in the day for my contribution, but I only joined concertina.net this week.

 

I looked up your Wheatsone thread dimensions in one of my dads old engineering books

It is called " Newnes Engineer's Manual" and was first published in 1940.

 

One thread chart is titled

 

UNITED STATES STANDARD FORM THREAD

INCLUDING S.A.E. STANDARD

 

Diameter 7/64 " U.S. Std. Threads per inch 48 , Outside diameter 0.1094" , Pitch diameter 0.0959" , Root diameter 0.0823" , Tapping drill size Number 44 drill.

 

This seems to tally with the Wheatstone thread to me.

 

Yours is just 2.4 thou. smaller than the standard outside diameter, that's good compared to mass produced screws that you buy today.

 

May be of use to other repairers.

 

Cheers.