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Discussion Starter · #1 ·
If you harden a rail and temper it, then by accident you harden and temper it a second time is it ruined ? I wasnt paying attention to my pile of rails and I did one twice.
 

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bullet175 said:
If you harden a rail and temper it, then by accident you harden and temper it a second time is it ruined ? I wasnt paying attention to my pile of rails and I did one twice.
No matter what or how many times you do it, if the last time you mess with it you properly heat treat it and temper it, you will be good to go. ak'sr4me
 

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bullet175 said:
If you harden a rail and temper it, then by accident you harden and temper it a second time is it ruined ? I wasnt paying attention to my pile of rails and I did one twice.
What type of fluid did you use to temper it? I know they make some fluid for tempering. I was going to quench it in water.
 

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Discussion Starter · #5 ·
I just quench in water and then temper in sand. Lime is good to use too. Back when I used to do machine work we used some sort of oil to quench with. The stuff stunk to high heaven when you used it though. It looked like molases but smelled worse than gear oil. The oil quench is a tad slower on the cool down and is supposed to help hold a parts tolerances better. It wont warp or fracture the part during the rapid cool down. But for what we are doing water should be fine.

While we are on the subject of this Ive noticed that when I get a parts kit in that still has the reciever pieces attached, it looks to me that they harden the whole receiver with the trunnions and rails already attached. the rivets are hard, the trunnions are hard, the entire reciever is hard. Ive got a friend of mine who has an electric kiln for doing glass work that will go to 1500. I was thinking about dropping one in there and doing the whole thing and see what happens. Any comments....
 

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I'm interested to find out how it goes bullet.
 

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bullet175 said:
I was thinking about dropping one in there and doing the whole thing and see what happens. Any comments....
IMHO the 2 things I would worry about is warping & being too hard(brittle) but the former should be kept to a minimum with the trunnions in place. As for the latter I think the ejector must be harder than would be good or useful for the overall receiver. To me, a hobby knife maker, differential tempering is the best, with the holes that have the most potential for wear and stretching being hard and the rest of the receiver softer(like a spring) and more shock absorbing.
 

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bullet175 said:
If you harden a rail and temper it, then by accident you harden and temper it a second time is it ruined ? I wasnt paying attention to my pile of rails and I did one twice.
Some of the best knifemakers go through several hardening and temper cycles and get excellent results. It has something to do with grain size and structure. You probably made them better.
 

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bullet175 said:
I just quench in water and then temper in sand. Lime is good to use too. Back when I used to do machine work we used some sort of oil to quench with. The stuff stunk to high heaven when you used it though. It looked like molases but smelled worse than gear oil. The oil quench is a tad slower on the cool down and is supposed to help hold a parts tolerances better. It wont warp or fracture the part during the rapid cool down. But for what we are doing water should be fine.

While we are on the subject of this Ive noticed that when I get a parts kit in that still has the reciever pieces attached, it looks to me that they harden the whole receiver with the trunnions and rails already attached. the rivets are hard, the trunnions are hard, the entire reciever is hard. Ive got a friend of mine who has an electric kiln for doing glass work that will go to 1500. I was thinking about dropping one in there and doing the whole thing and see what happens. Any comments....
I would give it a try. I would maybe disassemble and remove the trigger assembly and springs before heating. Let us know what you find out.
 

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-Quinch and temper-

As notorious as it sounds, on my "Vulcan" receiver nothing was hardened.
I bit the rails with a file before hardining.
So I took the easy way out instead of spending all the money on the fancy chemicals to quinch and temper by doing alittle research on metal properties. To demagnitise the metal or "rails" I used the ol' propane tourch to heat to around 1200 degrees or brite orange.
Then plunged into "Ice cold salt water", Yes (Salt) water. It does rust(surface) a tad but can be buffed out. And to use a good protectant. That is after you temper.
To temper: Heat the metal back to a dark blue, than let air cool.
The iodine in the salt combined with a quick quench is an instant "hard on"! Do a search and you'll find that "iodine" Is also a key ingredient in alot of the surface hardining compounds out there.
Many people say that a "Propane" tourch cannot heat 4130 steel to its hardining state like a "Map" or "Acedaline", to me that's B.S. You just need a little patients.
By "quinching" the part or peice this strengthens the internal carbon and the other properties of the metal.
By "Tempering" This is the surface hardining of the material. I would NOT suggest doing large parts in this procedure though. For the simple fact of warping the material. Use a kiln or furnace.
After Q&T on a peice of scrap stock, I burned up 3 Dremil bits just to get barely a 1/4" into the metal. If it's done right....It does work!
Making sure you get it right the first time, practice on a scrap peice.
If you continously keep heating and plunging, you could be breaking down the strength of the steel.....Making it very hard on the surface, but also very "Brittle"
After almost 2000 rounds.....No sign of ware on the ejecter!
Be carefull, the steam from the rapid quinch could be extremely harmfull!!!
Using oil to quinch is also a very good method to prevent rust and repell moisture. But can also cause a fire!! Again be carefull!
After all, you should clean your firearms by using a good moisture barrier regularly right? I'm guessing this would be a good method if you plan to store your rifle.......Or go swimming with it.
-Shadow-
 
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