Stainless steel galling ?

[Deadeye]

I may be working on a amt hardballer soon. I've read some of the threads on this subject and they mentioned galling. So I was wondering exactly what is galling? What causes it? How to repair it etc. Also I've heard it can be a problem when working with stainless (grinding,polishing etc.).
Thanks Deadeye

[John]

Those older stainless steel guns had the tendency to gall, if not lubed well. What galling is? I am not an expert in metallurgy, but I think it is something that is caused by the friction of the metallic parts causing a surface change, which affects the metal properties. I know, nothing concrete, but I have hardly finished my first coffee, so don't ask too much.

[Hawkmoon]

I am neither a machinist nor a metallurgist by profession, so I can't really explain exactly what it is any better than John. The result of it is an uneven surface on the metal. As far as I know there is no "repair" for it, short of removing some metal and welding in new, then re-machining. Minor galling can be cleaned up by careful filing and/or stoning, but that obviously loosens up the fit of the parts.

The best approach, obviously, is to avoid letting it get started. Keeping the slide and frame well lubricated is the key. What I've read suggests that the problem occurs when both parts are made of the same SS alloy, and they tend to be attracted to one another, causing a high-friction rubbing. Using good quality lube that will remain in place rather than run off as soon as the gun starts to get hot would seem to be the way to go.

[tombstone]

I was curious about this also, and found the following at a commercial web site that sells stainless steel fasteners. It seems to make sense...

"Galling occurs when the stainless steel oxide surface film breaks down as a result of direct metal contact. Solid-phase welding can then take place (whereby material is transferred from one surface to another). The symptoms of galling include surface damage and seizing and freezing up of equipment."..."Galling can also be reduced by using two different stainless steels, of significantly different hardnesses, on the mating surfaces. A Brinell hardness difference of 50HB may overcome galling."..."It is recommended that some form of lubrication be applied. Proprietary grease-type lubricants, containing tenacious metals, oils etc are available. Some commonly used lubricants contain molybdenum disulphide or nickel powder."

[Anopsis]

The best info I can offer is use a good grease like TetraGun's white grease - don't oil the slide rails. This is the only thing I know of that will extend the life of an old AMT 1911.

[pa_guns]

Hi

As mentioned above galling occurs when the steel welds and then tears. There are several things you can add to an alloy that will reduce this tendency.

A good lube is about the only thing you can do at home. The other simple thing is to avoid mods to the pistol that tighten up the fit. The more pressure you have at a single point the more likely you are to have a "coldweld".

Bob

[Deadeye]

Thanx fur du edamakashun fellers.