Extension handle for a Starrett solid-rod inside micrometer set

[Paul Jones]

Hi Don42,

I agree that the design in many cases will best meet the intended function and will work best with non-standard threads. This is especially true in large diameter part cases. I have done this many times.

However, in the case of Starrett using a 0.110” X 52 TPI seems a little odd when the standard National Fine (NF) No. 4 with a 0.112" X 48 TPI would have work just as well. When looking at the two different threads side by side it is difficult to distinguish one from the other without making the measurements. It could be the Starrett designs predate the established standards considering the L. S. Starrett Company was founded in 1880. Starrett makes very nice tools and we appreciate this.

By the way there is a fantastic YouTube video by John Sanders (NYC CNC) on a tour of the Starrett factory and one on my favorites and a must see episode.

Regards,
Paul Jones