is it possible to crack a milled receiver with a steel punch?


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PILMAN
February 23, 2009, 12:54 AM
I'm just wondering if it's possible to crack a milled receiver by accidently hitting it with a steel punch or a hammer say if someone misses the retaining pin?

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nalioth
February 23, 2009, 01:24 AM
It's possible.

Just how hard were you trying to hit the pin?

PILMAN
February 23, 2009, 01:41 AM
Not very hard at all. I'm not positive if it's a crack because you can't see it from all angles, it looks silver but if you turn it a certain direction under light, it looks black, it's not crooked like a normal crack, it's just like a small slant and it hasn't grown in size. I showed it to a FFL and he said he was pretty sure it wasn't a crack. Was on a VZ-58.

ThrottleJockey
February 23, 2009, 02:03 AM
Take it to a machinist, he will probably be best suited to answer whether or not it is a crack. Try to find one that deals with automotive cylinder heads and blocks. If it is cracked, he can also do a fantastic job welding it!

PILMAN
February 23, 2009, 02:07 AM
I was told it was in a non stress area, but everyones telling me you can't really crack a receiver like that especially a milled one with just a hammer or punch, and I know I didn't hit it that hard at all. It was just light taps.

ThrottleJockey
February 23, 2009, 02:12 AM
well, you can crack it. if the pin is tapered, and larger than the hole, and you force it through the hole......you get the idea. also, if there is a pin there holding some moving part or group of parts in place, I would have to say it is not a "non-stress" area. maybe not combustion force type stress, but stress none the less.

Mojo-jo-jo
February 23, 2009, 02:15 AM
You can buy a kit of penetrant chemical compounds that will indicate cracks in ferrous metal parts. I sold it at Advance Auto parts when I worked there a few years back. It was intended for checking engine cylinder heads and pistons for cracks. It's kept behind the counter--you have to ask for it. I think it was manufactured by "Magnaflux," and may have been called "Magnaviz," but I'm not absolutely sure. IIRC, it was about $20.

Maybe useful in your case.

PILMAN
February 23, 2009, 02:16 AM
it's the pin to hold in place the dust cover. Theres a plunger that holds it in place, it's very stiff and was told I needed to use a punch to get the pin out.

Eagles6
February 23, 2009, 02:22 AM
I seriously doubt it unless there was some underlying flaw and then I still doubt it. VZ58 in a non-stress area, darken with a magic marker and forget about it.

beatcop
February 23, 2009, 02:28 AM
-Determine if it's in a critical location.
-Try to inspect it with a jewelers loupe (10x mag) or greater. I've done some inspection work with a digital microscope and it's very easy to discrern whether it's a gouge or a crack.
-You can use stuff like Zyglo (liquid penetrant NDI) to find cracks in metal, but you also need a black light. You basically spray a surface, wipe it off and any cracks will "glow" under the light.
-Magnaflux machines are quite large and run an electrical current through the unit under test. You hose down the item with a liquid containing particles that flouresce under a black light.

More than you wanted to know, eh?

PILMAN
February 23, 2009, 02:32 AM
I can't even get pictures of it, I've tried with zooming in and light and it just doesn't show up at all, so i'm starting to wonder if it's just a deep scratch.

http://i74.photobucket.com/albums/i249/PILMAN/crack-1.jpg

You can hardly make it out in that picture, it's that silver thing tho by the ding.

ThrottleJockey
February 23, 2009, 02:36 AM
my guess is that you are fine. if it were a crack, it would likely start at the edge, like at the pin hole...

PILMAN
February 23, 2009, 02:44 AM
Theres nothing at the pin hole, it's just by that "ding" and it curves, it's very small. It might have been where the hammer came in contact. I've also heard I can use lighter fluid to check for cracks? I can't seem to find this magnaflux stuff online and I called machinists in town, they said they won't do rifles.

chrissmallwood
February 23, 2009, 08:31 AM
You can use a magnet(something more powerful than a refrigerator magnet) and some metal powder(if you ever you use a grinder than this shouldnt be too hard to find). This is the same as magnufluxing just cheaper. Stick the magnet near the suspected crack and lightly dust the area with the metal powder. If there is a crack the metal powder will react differently than if its not a crack. You should see the metal powder follow the line of the crack. I dont know how to really explain it properly hopefully someone else can do a better job of it.

beatcop
February 23, 2009, 09:01 AM
That ding is it? Photo may not do it justice, but it doesn't look like anything more than a small ding.

Doesn't look like a critical area at all.

230RN
February 23, 2009, 10:02 AM
Seems to me if the metal was soft enough to get dinged, it wasn't hard enough to crack from a punch blow. Maybe by expansion from trying to drive a tapered pin out the wrong way, but not from just a zot from a punch or a hammer.

Yes?

No?

Challenge me.

One thing you can do is spread some light oil over the area, wipe it off, and wait to see if any oil from any crack bleeds out again and darkens the blueing around a possible crack over a period of time... ten-twelve hours, more or less. Analogous to the lighter fluid method, but a little more reliable since the oil doesn't evaporate like lighter fluid.

Terry, 230RN

heron
February 23, 2009, 11:27 AM
Spread a little kerosene around the area and wipe the excess off, wait about five minutes and wipe it again. When it looks like you have it all off, dust the area lightly with baby powder or something similar (very fine and dry). A crack will show up as a dark line.

Really, though, what you showed in the photo doesn't look like a crack to me; it just looks like a tiny worn spot on the bluing/finish.

lesterg3
February 23, 2009, 11:38 AM
Lot's of good information on testing for a crack, but even there there are differing methods for different materials. The quality of the materials used are important.

The real likely hood is if this firearm was produced by a reputable manufacturer, this is not a crack.

However, you have not provided enough information (the pic was good), but who manufactured the gun?

What is the receiver made of, 4140, 1020, 1040 with heat treatment, or cast iron?.

I have only seen one receiver that was made from a casting and that was some manufacturer that I never heard of and can't remember the name, it was a cra--y gun.

Jim K
February 23, 2009, 02:57 PM
I may be wrong, but isn't that receiver painted? Could it be you just chipped the paint?

Jim

PILMAN
February 23, 2009, 03:13 PM
I don't think the receiver is painted, it has some sort of shiny Laquer grey finish.

The gun is made by D-Technik in the Czech Republic and the rifle is sold through CZ-USA.

I don't know the type of steel, all I know is that it's milled, not cast.

Seems to me if the metal was soft enough to get dinged, it wasn't hard enough to crack from a punch blow. Maybe by expansion from trying to drive a tapered pin out the wrong way, but not from just a zot from a punch or a hammer.

Yes?

No?

Challenge me.

One thing you can do is spread some light oil over the area, wipe it off, and wait to see if any oil from any crack bleeds out again and darkens the blueing around a possible crack over a period of time... ten-twelve hours, more or less. Analogous to the lighter fluid method, but a little more reliable since the oil doesn't evaporate like lighter fluid.

Terry, 230RN



I'm not sure if that ding was already there, or if it was possibly caused by the hammer. But if hit hard enough, metal will ding. Where that ding is, you can barely see it, but there was what appeared to be a small hairline crack although it could be a scratch. I'm going insane trying to find out what it is, but I guess I can try that babypowder method.

lesterg3
February 23, 2009, 03:39 PM
You can mill any type of metal.

PILMAN
February 23, 2009, 04:59 PM
CZ-USA says it's Carbon steel.

PILMAN
February 23, 2009, 05:30 PM
Cast 4140 chrome-moly steel

lesterg3
February 24, 2009, 01:51 PM
Cast 4140 chrome-moly steel is a very tough material, I have work for years with 4140 and it can take a huge amount of abuse without cracking. If this receiver is indeed 4140 this is a dent, not a crack.

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