Thread size?

[pabird]

I agreed to make a few dial indicator extension rods for a buddy and it went well until it came time to add the threaded portion. Wow those threads look small, no problem, good challenge I thought. Pull out the thread gage, check a few, no match! Oh-oh. The finest metric gage i have is .50 pitch. They seem finer. After some digging around I think the threads are 1.28mm x .55 pitch but I have no way to measure them. Can someone set me straight on the size? By the way, the indicator is a Starrett. Thanks,Al

 

[vlmarshall]

#4-48 according to this... http://www.wttool.com/product-exec/...rrett_?utm_medium=cpc&utm_source=SiteChampion

 

[pabird]

Thanks Vernon, I think I'm making this harder than it is :-[