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Stainless Screws binding on stainless PEMS

We are putting together a stainless steel cabinet made from 304ss with some population of 316L mixed in. We are using stainless pems and 18-8 stainless screws with lock washers. Every 10-20 bolts binds to the point that we can not remove it without snapping the bolt. These pems are 10-32 and the screws are 1/4" - 3/8" in length. We have gone as far as tack welding the pems in and running a brand new tap through them with and without cutting oil, and also with a cleaning pass. The interior of the cabinet will be a moist environment with some bleach present. What can we do to stop this. Should we use a different type of screw or Pem? or should we just put anti-seize on all two hundred screws in the unit? Thank you for your anticipated help.

T. Lynsey Hull
Sheet metal/OEM Manufacturing - Chester, Connecticut, USA
2006

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Dear Sir, a good solution to eliminating galling with SS hardware is to coat them with WS2 or Tungsten Disulfide. This process was developed for NASA for use on SS hardware matting with Titanium or aluminum. It works quite well and the components can be assembled and reassembled several times. The thickness of the coating is a nominal .000005.

Ed Fabiszak
Morris, Illinois, USA
2006

Hey mate. The reason your stainless bolts are binding up is because of the composition of the steel. it is very strong due to the way the particles are arranged. when you tighten stainless steel bolts and nuts the stainless sometimes grabs and creates burrs inside the thread. these burrs will never come undone. the solution to your problem is called never-seize a lubricant with nickel through it. this will stop the bolts seizing up and also protect them from corrosion. hope this helps.

Brad Day
- Adelaide, South Australia
2006