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Discussion Starter #1
I need to heat treat or harden my trigger pin holes like the OOW receiver has done.
Here is my problem, I am doing a bullpup project and have this front end piece that has it's own trigger. I have put some time into this piece and when I went to drill the hole's for the trigger pin, I used someones drill press.

Crap crap and crap! It screwed up the first friggen hole like some triangular hole. So I took it down to my welder and he says he can fix it by putting a copper plate on the inside and then filling in the hole.
O.k. so maybe I dodged a close one. Once fixed I wanted to harden the hole's but I am afraid I will screw it up.

I looked up the directions about heating with a torch untill cherry red then dunking in oil, clean off the carbon and heat up again untill it turns blue and let air cool.

Anyone here do this?? I do not want to screw it up being I am so close to finishing.
 

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Do a search on "heat treating". There are several posts on this very issue. You should find your answer.
 

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Discussion Starter #3
Anyone ??

Maybe someone could tell me if this procedure is correct, and I will try and do it.
 

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That is what I have been doing and it seems to work fine. Try it on a scrap piece and then hit it with a file. You will see the difference
 

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I tried the heat and dunk method and it didn't work to well the holes would start to open up. You could see the the pin movement when you chocked the hammer back and pulled the trigger.

As I saw this was becoming a problem and not wanting the hole to get to big I disassembled the rifle and used "Kasenit" to harden the holes. This is what I did:

1. Remove all parts from the receiver so you just have a barreled action.

2. Placed a .250" X 1" steel backing plate behind the hole (use a clamp to keep it in place).

3. Heated (I used oxy-acet) the hole area (do each one individually) to cherry red, used a small scoop (like a measuring spoon 1/4 teaspoon) to scoop some "Kasenit". While the hole area is cherry red pour the "Kasenit" into the hole (you have the steel backing plate there (item #2) so the "Kasenit" stays in the hole. Heat the hole area again to cherry red, this melts the "Kasenit" to harden the hole area (you might have to do this twice to make sure).

4. As per the directions on the "Kasenit" plunged the reveiver into a bucket of clean water.

Basiclly your following the "Kasenit" directions. This seemed to stop the holes from opening.

Oh, as a side note I also hardened the left side receiver selector hole (small). For some reason this hole started to open up also. The "Kasenit" is also very good for hardneing the ejector. But be sure all the work is completed on the ejector before hardening. This is because once hardened it will break if you try to bend it (I think grinding is okay).

Hope this helps.
 

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Happy Camper
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Did I hear "bullpup" ????

If I did, then I'd love to see what's going on with your project. I'll show you mine if you show me yours... :D

Using an AMD kit?

Actually I'm not too far along on mine... yet. Making headway and tackling the issues one-by-one. I'm using a '74 as the basis.
 

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Discussion Starter #7 (Edited by Moderator)
Yep a bullpup. I had a kvar kit and see the flaws. I have designed a trigger set up and am building the rifle around it. There is no binding or rubbing going on and have only one slight bend.

I have spent many a night thinking, designing and testing.

I now just want to do the finish up work of hardening what needs it and doing a good finish. Right now the rifle is back into pieces so I can finish the loose ends.

a lot of the small parts are of my own design and have been custom made.

It is an sar2 on a oow rec.

I will post some pics when its finished.
 

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Happy Camper
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Cool! I'm building based on the Groza and am awaiting my mini mill replacement to arrive, then I'll be completing the build. In fact I just got my 2nd trigger guard that I'm going to use for the forward grip. Hate to destroy a perfectly good trigger guard, but it's for a good cause! :D

I'm planning to use a steel bar that is milled thinner where it runs down the side of the magazine well. I've also considered a 2-part bar to ease disassembly. Careful observation of the few Groza pics suggest those have a 2-part linkage. I think it may actually make the geometry easier to function. However we shall see. I have a few ideas to make it work. I've even considered a "pusher" design similar to the Valmet 82's linkage, but kept internal like the Steyr AUG's linkage.

I'm going to start a "Bullpup Builds" thread so we can compare notes. I know of at least two other bullpup builds but have heard only bits and pieces.
 

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Discussion Starter #12
Yes, I too have already cut my trigger gaurd. I am going for a cross between the Groza and the new Ukraine Vepr. http://www.world.guns.ru/assault/as68-e.htm

I tried a bar but it scraped the bottom of the front trunnion. I went with a thick wire. Being it is a sar 2 it has more room width wise to allow a thicker wire. This wire will not accomodate sar 1. The main points are the trigger gaurd rivets bind the wire upward. therefore I eliminated the rivets, and it is perfectly flat and smooth. Kvar's problem is the trigger gaurd rivets press the wire up into the hammer spring and the plate that sits to the side. (Part of the rail). I also have protected the wire from any possible rubbing against the hammer wire.

My wire is in a direct line, not bent here and there like kvar's.

Heck there are much more finite parts, but it will take some time to explain.
I hope to get pics or maybe a diagram of what I did, and am doing.
 

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Happy Camper
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Pantera said:
The main points are the trigger gaurd rivets bind the wire upward. therefore I eliminated the rivets, and it is perfectly flat and smooth.
I am using a thicker bar, and bending it over the rivets, just underneath the hammer. Will have a little bend in it but I am confident that the thickness of the material I'm using won't cause flexing.

I'm also going to polish the trigger hooks and hammer for a nice clean release.
 

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Discussion Starter #14
That's what I am going to do as well. Polish every contact.
I still have yet to make my new, longer gas tube and barrel cover. I am taking my time on this.
 

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Discussion Starter #16
Oops, Huked on fonics werked fer mee.
I meant to say, the gas tube cover will be longer, not the gas tube.
It has the standard gas tube but I removed the front holder and am moving it forward to meet up with the handgaurd.
Crud, I hope I explained that right. I will scan some of the parts I have and try and post them.
 

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just in case you really want to get into heat treating a whole reciever , I ran across this and thought this might be usable .... it does happen to be in PDF format so you need abode acrobat to be able to read it .... http://www.thelitterbox.org/librum/i-vfp/furnace.pdf (for some odd rreason why do I think hcpookie will be building one of these in the not to distant future ......)
 

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Happy Camper
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LOL

That's TOO scary you said that. I already have...

http://pookieweb.dyndns.org:61129/foundry/foundry.htm

I still have not fired it up, and I don't want to jinx my plans, but my goal is/was to make an investment casting setup for the more detailed bullpup parts among other things like scope rails, etc. so WHEN I get set up, I'll be able to more quickly (and cheaply) produce these items.

Steel parts will obviously be outside the abilities of the foundry, but that's what the mill is for.

I'm really jinxing things now, but I also want to make an affordable M203 clone in 37mm. More affordable than the Shivak receiver. "one day" I suppose...
 

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Happy Camper
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Pantera said:
Oops, Huked on fonics werked fer mee.
I meant to say, the gas tube cover will be longer, not the gas tube.
It has the standard gas tube but I removed the front holder and am moving it forward to meet up with the handgaurd.
Crud, I hope I explained that right. I will scan some of the parts I have and try and post them.
Please do! I'm right there with you, have already considered that. I am probably going to turn out a custom wood handguard on the lathe for the first one, then move to either Delrin or some other plastic that will be better with the heat. Phenolic (like on the Czech VZ.58) would be ideal but it is expensive. In fact, you may want to reference the VZ.58 if you have not already done so to see what it would look like.

That, and the STG-940. I've been looking, in vain, to find an STG-940 handguard kit. BEFORE the AWB, there was a company called "Stock Options" (try searching for THAT on the web) and they made it. But that was '94. I think they are now Ace Stocks - aka riflestocks.com. WOuld love to talk them into making a limited run of this stock set. That handguard is ultimately my goal, or something close to it.
 
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