What's new
What's new

Pre-Plate Thread Sizing Question

F35Machinist

Plastic
Joined
Nov 3, 2021
I am trying to turn some external metric threads that will later be coated with a plating thickness of .001". Machinery's handbook says that for 60 degree threads, the change in pitch diameter is 4x the plating thickness. I will be using a sharp "v" style threading tool to make the thread. My understanding is that to make the threads correctly so that it gages after plating, I would have to reduce the major diameter by .002" and the thread depth by .004". Is this right?
 

couch

Cast Iron
Joined
Jun 10, 2009
Location
Anaheim, California
I am trying to turn some external metric threads that will later be coated with a plating thickness of .001". Machinery's handbook says that for 60 degree threads, the change in pitch diameter is 4x the plating thickness. I will be using a sharp "v" style threading tool to make the thread. My understanding is that to make the threads correctly so that it gages after plating, I would have to reduce the major diameter by .002" and the thread depth by .004". Is this right?

Thread pitch diameter will need to be .004 smaller. Not sure if that’s what you meant by depth (as in radius or diameter), but sounds like you got it.
 

Triaged

Aluminum
Joined
Dec 31, 2016
Is this part getting made to any specific spec? Some thread spec's say you can't go more than .001" smaller than the min finished pitch dia. prior to plating.... But Couch is right.
 








 
Top