The authoritative public forum
  for Metal Finishing since 1989
  

  -----

Paint ingress in tapped holes

I am painting components with up to a 100 tapped holes in them of 5, 8 and 10 mm diameter and would like some help on eliminating the costly operation. I have considered plugging but this is also a time consuming operation....is there any new innovation in the market place?

Ian Clarke
- Sheffield, Yorkshire, England
2003

Hi,

I had the same problem, and the only conclusion was to use plugs, there doesn't seem to be any new invention/product to eliminate the build up of paint around the tapped holes. The solution that I tried and seems to working successfully(last 3 months) is to machine a counterbore around the tapped hole, which is about 1 - 2mm larger in dia. to that of the hole (i.e. if the hole dia. is 8mm, make the counterbore 10 mm), and have a depth of equal size (1-2mm deep). This is a bit trial and error ( I'm currently working on a system were by which a standard counterbore size will set for each tapped hole size). This seems to eliminate the "crusting" around the hole entrance, as the paint fills the counterbore. Remember to plug the tapped hole and leave the counterbore bare.

Cheers,

Steve Smee
Thermo Electron - Liverpool, UK
2003