View Full Version : Sharp edge in metal

November 2, 2007, 11:14 AM
I just bought a new Walther ppk/s. When I got home I disassembled it and found a small, sharp, protruding defect in the metal on the back edge of the barrel. It looks like its probably from being in a vice or something during manufacturing. It is small but rubs very slightly on the slide. Would it be fine to sand or file this off? Can anyone recommend a tool and method to smooth this out?

November 2, 2007, 11:45 AM
Just use a gray wheel on it, stop at your smiths, he will have one.

November 2, 2007, 11:51 AM
would doing so harm the finish?

November 2, 2007, 12:26 PM
The gray wheel is a fine finishing wheel, it comes in various "grits", use a fine grit wheel and it will both debur the edge you wrote of and also polish it. Be careful to stay away from edges you want to keep as they are. Practice on a piece of barstock, offer the gunsmith compensation of course, and you may not be able to find one who will let you use his wheel. The wheels are expensive, and a new guy typically will wear grooves in the edge of the wheel. It's a natural (To the guy who pays for the wheels) practice to favor the area of the edge of the wheel that is higher, or if it is flat to play the part back and forth across the wheel edge. If you were here and asked this question I'd show you how to do this, but not everyone will.
I have a S&W PPK/S that made bloody tracks in the web of my right hand when I shot it, the gray wheel rounded out the sharp inner edges of the back rails of the slide so you would not know it wasn't made that way if you saw it. That helped with the shooting pains :)

November 2, 2007, 12:30 PM
Oh, the wheels are often called Scotch Brite, but they are made by quite a few makers. You can buy a 6" wheel and put it on your grinder, for about $35, larger wheels cost a lot more.

November 2, 2007, 12:50 PM
thanks for the input. Do you think i could use a needle file to do the same thing or would that leave a rough surface?

November 2, 2007, 12:54 PM
what about a Scotch Brite hand pad? Does the high rpm of the wheel provide a different result regarding the polish?

November 2, 2007, 01:03 PM
If it rubs, it'll wear off as you put a few hundred rounds through. If it bugs you, I like the idea of a needle file or a stone. Finish up with a gun-oil soaked fine steel wool pad.


Bill DeShivs
November 2, 2007, 01:32 PM
Use the file. Just cut the burr off carefully.

November 2, 2007, 01:36 PM
Myself I'd use a file and follow with a gray wheel, so it doesn't look like it was filed. The gray wheel will make it look new again.

November 2, 2007, 03:36 PM
thanks for your replies. They were helpful. It is a very small spot and barely visible. If i only use the file would i have to worry about and increased potential to rust in the area filed? More specifically, does the smoother surface created by the wheel have a preservative effect on the metal or is it just cosmetic?

November 2, 2007, 04:15 PM
Shouldn't effect corrosion.:)

November 2, 2007, 05:10 PM
a million thanks for your help. im going to do the job tonight. will take before and after photos and post them.

November 2, 2007, 07:08 PM
the above photo is before using a needle file and 1200 grit sand paper.

the above photo is after.

its not very pretty... its not very ugly... but it worked. Its slide moves more smoothly.

November 3, 2007, 12:34 AM
That was probably the hood the barrel mounts in, they are really thin things and can be beat up very easly before the barrel is pressed in or while pressing it in.

November 3, 2007, 08:48 AM
Just a personal note, anytime I use abrasives around machinery I carefully clean every bit of anything that gets loose away. I don't like the idea of a few grains of grit cycling every time I use it. But you probably thought of that.
I was visiting a machine shop in Alaska, a guy was emery clothing a long shaft for fit or dimension, and when he was done he took an air hose and blew it clean while in the lathe!. A death sentence for that lathe, and no one thought a thing of it but me. Not my lathe so I didn't say a word.:(

Bill DeShivs
November 3, 2007, 12:45 PM
Lathe bearings are sealed.
It is a good idea to clean thoroughly. I blow guns out with brake cleaner, then re lube.

November 3, 2007, 01:14 PM
"Lathe bearings are sealed."

Lathe ways are not.

And even sealed bearings will allow debris in if you spray it around hard enough.

November 3, 2007, 02:15 PM
I don't know what kind of lathe Bill has, but every commercial lathe I know of uses labyrinth seals. Air blasts around a labyrinth seal is, well, to be kind, ignorant, that's not just my opinion, many machine tool are marked "Do not use air". Way seals are notorious for being short lived in effectiveness, they wear out much faster than the lathe does, unless of course someone blasts abrasives onto it.:)

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