hardware for ss bolts

[tbeau]

We have a cut-off saw that has SS socket bolts with carbon steel t-nuts for the clamps and hold downs. The nuts are seizing due to the coolant. We replaced the bolts and nuts and added corrosion inhibitors to the coolant but my questions are, should we switch to SS nuts or will galling be a problem? Also, does Cu or Ni based anti-seize help this or help with the seizing of the carbon steel nuts? I'm a recent grad and haven't had any experience with this so I'm looking for some help. Thanks.

 

[unclesyd]

You could use silicon bronze hardware. All our holdowns hardware used on our machines that drill 316 SS is silicon bronze. We have used these for years with various coolants and I can't recall any problems.

 

[SnTMan]

tbeau, switching to SS nuts cold replace your seizing problem with a galling problem. No help there.

Before totally changing fastener materials, I would try the anti-seize, and don't be stingy with it.

Cheap fixes first.

Regards,

Mike

 

[TVP]

Galling very well could be a problem with stainless steel nuts, unless you purposely design around it (perform a keyword search here using stainless steel thread galling). I would just use a suitable anti-seize/thread lubricant together with a zinc-plated steel nut or maybe a silicon bronze nut.

 

[tbeau]

Thanks. I'll look into the silicon bronze and anti-seize. Any thoughts on Cu based versus Ni based? This is a saw for a mettallurgy lab. Maintaining the one we have rather than spending money on something else. Thanks again.

 

[CoryPad]

I can attest to corrosion of the clamping parts in metallurgical lab saws. We have several threaded connections that are corroded and will not turn.

In general, nickel is likely to be stronger and more corrosion resistant, but more expensive also.

 

[unclesyd]

Certain nickel alloys will gall, gall, gall.
In our Met Lab the hardware on 3 slow speed diamond saws, one high speed diamond saw, and a large abrasive saw all clamping components are Si Bronze, Nickel plated brass or cast iron. All screws in the clamps are Si Bronze.

 

[tbeau]

This is an abrasive saw. The hardware for the clamps is SS bolts and plain carbon t-nuts. The Ni based vs Cu based comment I made was referring to anti-seize compounds. I've only had experience with Cu based and wasn't sure if the Ni based stuff was preferred or required in SS applications

 

[EdStainless]

Since this is low temp try the Cu anti-seize.

Si bronze or Al brass would be my choices to mate with SS.

= = = = = = = = = = = = = = = = = = = =
Plymouth Tube

 

[CoryPad]

Sorry for the misunderstanding. The Ni-based or Cu-based anti-seize compounds should perform essentially the same.

 

[saberblue]

The coolants typically used in abrasive cut off machines(true solutions) tend to serve as good electrode lites when they dry out -- (they are primarily salts of one kind or another dissolved in water). This kind of a conductor mixed with all the different metals is a recipe for galvanic corrosion. There is virtually no way of preventing it (taking it to 0) but a light coting of water resistant grease on the mating surfaces will keep the coolant out and prevent the galvanic cell from forming thus reducing the corossion to a point where it should not present a probem.



A.R. "Andy" Nelson
Engineering Consultant
anelson@arnengineering.com