Machine Shop on Peninsula / Bay Area

[SandHill]

I have an AK rear (side folder) trunnion of questionable origin and not sure if they used good quality steel or hardened it. Want to get it tested in a Rockwell hardness tester. Anyone know of a machine shop around here that would do this kind of thing inexpensively? Alternatively, anyone got a REALLY well equipped garage who could help me out?

Cross posting to my local section.

[kcstott]

And you think finding a Rockwell tester will help??

So how hard should it be??? (Asked the smartarse tool maker)

And you also know that hardness has zero do with toughness over all?? I mean it all depends on what steel they used. 4130/40 is as tough as it's ever going to get at 35-40 Rc and that can still be machined, drilled, tapped, and filed.

That rear trunnion could be made of A-36 and would still be fine to use. It would be soft but it would be fine.

[SandHill]

Well, A-K Builder's site claims his are "heat treated to 40-46 Rockwell like the originals" http://ak-builder.com/index.php?disp...oduct_id=30258

His have a pretty good reputation, so 40-46 is what I'm hoping for. I have read on other boards that 35 is probably enough. The soft ones from DPH a few years ago were reputed to be about 10. So I expect its kind of binary in terms of possible outcomes just because there is a limited number of known producers / versions.

I am not a tool maker. That is why I come here for wisdom. Please bestow some on me.

[6mmintl]

try the file test, most files are 48-50C (should grab trunion with resistance to cut metal) , maybe the cheaper ones are lower around 45-46C and will skip over metal.

Its not real scientific but requires some regular usage with known hardness files to develop a feel for "relative" hardness of your sample piece. it helps also to know the exact hardness of various files used to test.

Its something you learn/use over many years to get a relative feel for material and is useful, Hardness tester is the way to go but then you have to know what to do with the more precise data.

[SandHill]

"......requires some regular usage with known hardness files to develop a feel for "relative" hardness of your sample piece.....

Its something you learn/use over many years.......

Thanks, but I am afraid I have no such experience. Any ideas for a machine shop around here that would have a Rockwell hardness tester?

[w210838]

Whats it doing that has you worried???

[1flhtk4me]

Whats it doing that has you worried???

Good question.

[SandHill]

Whats it doing that has you worried???

Trunnion hasn't done anything yet. Consensus on one of the AK boards is that its (probably) a cheap Chinese knock off made of soft metal that will crumple if I attempt to rivet it into a receiver. But there is another (Taiwanese) manufacturer that properly heat treats the metal and their's are supposed to be good to go. So my thinking is that the trunnion is likely either from one or the other of the two manufacturers, and if I can do a hardness test, I will know which one.

[Chewbaca]

Just try and rivet it in . If you rivet the thru rivet with out a problem your golden . If it deforms on you drill it out and send that worthless trunnion back to that website you bought it from for 99$

[Chewbaca]

If you need help let me know , in out of San Mateo and have all the ak building tools imagineable and won't charge you too much for some simple work

[Hova]

Just try and rivet it in . If you rivet the thru rivet with out a problem your golden . If it deforms on you drill it out and send that worthless trunnion back to that website you bought it from for 99$

No don't do that!!!! Guaranteed the trunnion is waaaaay too soft. We got it all figured out here...

http://www.akfiles.com/forums/showthread.php?t=204352

OP, didn't you end up returning this?