Stupid question of the week: What's "galling"?

[jfh]

There's good pictures and descriptions in this thread.

Historically, insofar as 'modern' firearms goes, the concern about galling was a topic du jour when stainless semio autos started being commercially produced--call it the Eighties. The concern, of course, was about stainless slides / frame wear. I do not recall ever seeing pictures of such damage, however.

Jim H.

 

[Speedo66]

Those auto parts pictures reminded me of when my daughter said there was a "noise" coming from the front brakes of her car. For how long? "A few months".

Took the brakes apart to find the brake pad gone, the metal brake pad backing plate gone, and the caliper piston doing the braking on the rotor!

Much additional metal bonded to the rotor, i.e., galling.

It made some "noise" my daughter said.

 

[Duce1]

Those auto parts pictures reminded me of when my daughter said there was a "noise" coming from the front brakes of her car. For how long? "A few months".

Took the brakes apart to find the brake pad gone, the metal brake pad backing plate gone, and the caliper piston doing the braking on the rotor!

Much additional metal bonded to the rotor, i.e., galling.

It made some "noise" my daughter said.

HA! so I am not alone .

Really bad when you daughter and then your wife say ! Hey my car is doing the same thing and I forgot to tell you ?

 

[7X57chilmau]

Heh.... I had the wife take a basic auto mechanics course way back when... She can do her own brake jobs (but chooses to let me do it) and her own oil changes... She has some respect for strange noises as a result.....

I figger the daughter will get some learnin' done by the time she's 12 or so...

J

 

[Carl N. Brown]

Galling ( Mach. (of either of two engaging metal parts) to lose metal to the other because of heat or molecular attraction resulting from friction) is really galling (irritating, vexing, exasperating) when it happens between the slide and frame of a handgun. The buildup from friction seems to cause more friction.

I keep a copy of Random House Webster's Unabridged Dictionary on my computer and try to keep it open instead of using a spell checker. Before looking it up, I would have posted galling is like pernugraffy, I'd recognize it if I saw it but I didn't have a definition.

The really stupid questions are the ones you don't ask and never learn from.

 

[1KPerDay]

Those auto parts pictures reminded me of when my daughter said there was a "noise" coming from the front brakes of her car. For how long? "A few months".

Took the brakes apart to find the brake pad gone, the metal brake pad backing plate gone, and the caliper piston doing the braking on the rotor!

Much additional metal bonded to the rotor, i.e., galling.

It made some "noise" my daughter said.

I bet you made some noise yourself.

I would have posted galling is like pernugraffy,

Now where'd I put that dictionary? LOL

 

[Oldfalguy]

When I have heard the term Galling associated with firearms is when one has a 357 magnum pistol and then proceeds to shoot copious amounts of 38 spcl in it- That portion of the cylinder chamber which is exposed (not taken up by the longer case) changes a wee bit and results in it being a bit harder to chamber 357 on down the line without a pretty good cleaning- Same with 44 spcl in a 44 mag-
Another example is the chamber face of the cylinder- changes color pretty quickly from the ...lead I suppose, not friction-

 

[mustang_steve]

Galling is a common issue in die casting, where the softer metal (what's being made) welds itself to the die, then the still not fully hardened casting gets torn when it's being extracted from the die. It can happen outside of die casting, but that's where I've seen the most frequent cases of it.

So you'll have the piece with build-up, then the piece which got eroded or damaged by the process. There's always at least two pieces that get screwed up by galling.

 

[mete]

In all my metallurgical career galling has always been 'cold welding' of moving parts.It's made worse by soft materials, rough materials, lack of lube or poor lube ,high pressure between parts. BTW metals are not molecular ! They are crystal structures with metallic bonding.
In the gun business a typical galling problem occurred in the early use of stainless steel but the companies have solved that for the most part .There are lubes specifically designed for stainless steels and high pressuure applications such as hinge pins on O/U shotguns .One I have is RIG +P+ [no longer made].
Galling is a gun term that many have misconceptions about and misuse terms . Another is "erosion" of barrel throats. It's not erosion at all but pick up of carbon from the hot gases and subsequent cracking of the steel.

 

[Legionnaire]

So would this be a fairly accurate summation?

Friction with lubrication leads to polishing, whereas
friction without lubrication leads to galling?

Or is that an oversimplification related to the amount of (how does one measure?) friction? Someone mentioned dry-firing. Many suggest dry-firing revolvers (especially Rugers) so that they "slick up." That's friction with the expectation of polishing ... not galling.

 

[7X57chilmau]

Galling will only happen with certian materials in contact.... Typically like materials, like 2 identical alloy stainless steels....

Basically they have to be similar enough that they'll agree to weld together without extreme pressure or temperature.

Aluminum galls on aluminum, but won't on steel, generally speaking, for instance.

It is more than just dry friction wear.

It is dry friction leading to contact welding and tear-out.

J

 

[Legionnaire]

It is dry friction leading to contact welding and tear-out.

Got it; thanks.

 

[Duce1]

Galling will only happen with certian materials in contact.... Typically like materials, like 2 identical alloy stainless steels....

Basically they have to be similar enough that they'll agree to weld together without extreme pressure or temperature.

Aluminum galls on aluminum, but won't on steel, generally speaking, for instance.

It is more than just dry friction wear.

It is dry friction leading to contact welding and tear-out.

J

Have you ever worked in the machine tool industry ?

I have seen Alum. friction weld itself to 12 inch and 24 inch faces mills made steel with carbide inserts many times .

And in return I have seen Alum friction weld itself to steel ?

Kind of has reason to know that it all depends on the circumstances .

 

[metalhd9034]

galling

Always happens to our stuff at work. Especially on male/female threaded pieces. We get around this by nickelplating the threads on one of the pieces so there is a different alloy on mating surfaces. Dang! too many innuendos in one description!