I want to use your threaded standoff, Part Number 12040RSS???-12 for a panel thickness of 10 GA sheet steel. I don’t want to swage it, and after flaring, the shank must be flush to under-flush.

How do I figure the shank length? The countersink will be 82 degrees.

We will assume you are countersinking to approx. 1/2 panel thickness – the recommended depth. Panel thickness in the drawing below is represented by T.

We start with known data and then apply the formula below:



  • 10 GA = .1345 Nominal thickness (T)
  • Shank length is therefore: .067 + .088 which yields .155. To ensure that shank is flush to under-flush, reduce the .155 by .010, resulting in .145.
  • Your complete part number would beĀ 12040-R-SS-.145-12.