Did Automag Sears come from Roswell ?

[Flatliner333]

Just Kiddin. What exactly are AGD sears made of ? How are they made and what kind of coating is on them ?
For my "spyderMAG" mod I decided early on that I wanted to fabricate a new sear and position the rod arm behind the "flipped" solinoid instead of modifying the stock sear to work with the spyder frame sear.I am commited now as I have removed the spyder sear and there is no going back.The design of the fabricated sear is ok but even after quench hardening the metal they dont last very long. If I remember right a hardness test on the AGD sear yealded a Rockwell "C" scale hardness of aroud 85 and a PMI test showed it appears to have a high carbon content. After quenching the sear I made it only went from a high "B" scale to a low "C" scale.
I am now trying to modify the bottom of the stock AGD sear. I have cut off the original rod arm and I want to weld another one farther back.Has anyone had much luck welding on these things if so what process did you use.My metalurgist tells me the AGD sear might be cold rolled and might not react well to high heat.I am a true redneck so I use J.B. Weld on a lot of my projects with good results....but not here the arm snapped right off.

Thanks for your help

[DevilMan]

Sorry I can't help you in this matter.... But I do know that the Sears are DAMN HARD!!!!

Best of luck to ya!

DM

[TwilightG]

Luke did some Spydermag mods a while back and would modify the sears to work w/ the spyder sear.
he might have some good info on this

[secretweaponevan]

"The sear itself, which is made from hardened steel and cadmium plated for long life."

@~3:15

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[Flatliner333]

Sear

Hey...I have that tape..Guess I should watch it again.

[Spider-TW]

I have only observed the failure of one. I think it had been filed before and even after I cleaned off the burrs and flattened it back out, it wore quickly. This made me think it was surface hardened. I've read of that behavior being true of case hardening in particular.

Other than that, I've seen two different pictures of sears broken at the sear pin hole with what appeared to be a brittle fracture.

If you have a scrap, you might test it after grinding different amounts off and see if it has a hardness profile.

[XM15]

Its most likely a tool steel like A2 or O1. I would doubt its made from 4140 or 8620 carbon steels. Its not usually a good idea to weld harden steels. You can try it and see if it works the worse thats going to happen is it will fail. There are M1A1 rifles floating around out there that were made in the 70's from demilled (cut up) M14 receivers and welded back together. Its not some thing I would like to trust with my face next to it.

[Automags for life]

What kind of quench?

What kind of quench are you using? Water or oil? Using oil will help add carbon back into the metal and it will cool slower and there are certain steels that lend themselves to hardening better then others, I think A1 tool steel is supposed to be one of them. In the past when our company needed anything heat treated we usually ended up sending it out. From what I saw inhouse it seemed difficult to get exact results without alot of practice. I would speculate that maybe you weren't getting it hot enough before quench if it wasn't hard enough. We had the opposite problem getting stuff too hot, to where it turned brittle. There's a difference between quenching at dull cherry red (better IMO) and bright orange. You also need to be careful how you lower the part into the quenching element as if you go sideways with a sear it could end up cooling the one side first and bending like a banana. Like XM15 welding hardened steel will soften the steel where the welding is which may or may not be a bid deal, and they can weld poorly as well.

[Flatliner333]

Quench

We heated it up to a bright Orange and quenched it in water.I am fortunate enough to work at a weld test facility and we have an in house metalurgist and CWI's and such. I wanted to try and case harden these with this stuff called Cherry Red that you dip the part in after it is Red and then quench it but I didnt want to pay what they wanted for it and I only needed a small amount.I am going to try and Mig weld it tomorrow and if that dont work I will try and get some tool grade steel and start from scratch.

[Automags for life]

Sounds like you've got some good stuff at your disposal, shouldn't be too hard to pull off, with that kind of help. Let us know what you come up with, would be interesting to hear. What kind of steel did you start out with?

[eXo_oUtSiDeR]

i think rt sears are made from carbide or at least have carbide inserts

[Automags for life]

Don't think so

I took a good hard look at mine last nite, (supposed to be a RT sear) and it looks stamped. A piece of carbide that big would probably run you $200 at least. Usually production on something like that goes like this start with a steel that is somewhat soft so it's easy to machine, stamp, form. After the basic shaping is done, then you send it to a heat treater to get it heat treated, case hardened, etc. Then you send it to place that does coatings and have a protective coating applied like cad plating.