[TowerTalk] Stainless Steel Galling

[Charlie Gallo]

On 6/25/2010 Larry McDavid wrote:

>  Cyclic motion of stainless 
> against stainless is a sure cause of galling.

Yes - BUT

I probably beat on a set of stainless fasteners worse than just about anyone - I ran a vibration testing lab, and we had a fixture that held down units that had 3/8" stainless threaded rod, and stainless nuts (hey, they were a "stock room" item)

These rods were exposed to EXTREME vibration by 'normal" standards probably 4 hours a day, with a bolt/unbolt cycle every 10 minutes (for those of you who wonder - WS-6536 Vibration standard - .02g^2/hz - if I remember my numbers right)

Did they Gall?  Oh Heck yes

BUT, we would get say 6-9 months before the galling got bad enough that we'd toss the rods/nuts, and make up another set

Based upon that, you have to start to wonder if we are really beating a dead horse, or that if we properly sized our attachments (to keep loading 'reasonable'), and took a modicum of care (any lube in there - or even the dreaded loctite to keep the stainless off the stainless/stop the rub cycle) are we "good enough"

For that matter - do we really care if it galls?  It's been a number of years since I did any tower work (old and fat), but I never reused hardware.  So long as we can get it apart - a nice battery powered "wizzer" tool, cut the bolts, replace as needed

-- 
73 de KG2V - Charles Gallo
Quality Custom Machine-shop work for the radio amateur (sm)