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Discussion Starter · #1 ·
Will a Propane torch like the one below give me the proper heat to harden my rails using Kasenit from Brownells? Otherwise, what would you guys recommend as a cheap alternative?
 

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I don't know if you will be able to develop enough heat with a propane torch.

You can buy a Mapp/Oxy kit for around $40 from a Home Depot or Lowes.
You will need one to silver solder your muzzle device on anyway, no way is straight propane going to be able to do that.
 

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Discussion Starter · #3 ·
DA**! Another $40. Anyone know of a cheaper alternative or a place to find a cheaper Mapp/Oxy kit?

One last thing 762, when you install the rails with the #10 bolts, did you drill the holes in the receiver first and then use these holes as a pilot to drill through the rails. Or, did you do the holes directly through the receiver and rails all at once?

http://www.gunco.net/forums/showthread.php?t=1073&highlight=rails
 

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I only bolted the rails in one time, to show it could be done, the rest were welded.
The rails are bolted in using 4-40 bolts, don't use #10's they're way too big.

Clamp the rail in place, and drill the receiver and rail together.
 

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Discussion Starter · #5 ·
you know I checked at HD for "4-40" bolts and could just not find them. Where did you get yours from? Could you send me a link to where I could find some with those specs and look the best on the outside of the receiver?
 

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I have not tryed it myself but I think MAPP gass will be hot enough to do your rails and it will work in your torch head. I delieve others have done this. Has anyone here used MAPP for this?? how did you make out?
 

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git er' hot!

I'm sure most of you know this but the "proper" heat for the rails is a dull cherry red. You basically have to "tool harden" the steel. That requires the metal to get to a cherry red, qench- then take the metal back up to a bluish heat, and let cool a number of ways. one way is to let it sit in a bucket of sand or powdered charcoal until the metal is cool. the metal absorbs some charcoal into the surface making the carbon count higher. the idea is to get the metal hard, but the harder it becomes the more brittle it becomes...
i'm no expert but i recommend you follow some of the instructions people have posted on here or other places-and/or pick up a book on blacksmithing. The procedures and wording blacksmiths use is much easier for "common folk" like me to understand...as opposed to some book from NASA or whatever the hell else you can find. I did my rails in a blacksmiths forge and did the second quenching in the carbon. the first was in oil. Havent put em in yet but they are much harder then when i got them in the mail.
hope this was helpful. If I'm wrong about anything-correct me and AS ALWAYS, GOOD LUCK!
 

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yosuthnmasa said:
you know I checked at HD for "4-40" bolts and could just not find them. Where did you get yours from? Could you send me a link to where I could find some with those specs and look the best on the outside of the receiver?
yosuthnmasa, send me a PM or an email and we could work out details. I have the 4-40 screws and could get them to you (I have a source for them not even 5 minutes from my house if more are needed).
 

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Discussion Starter · #9 ·
As far as the hardening goes, I think I am going to pick up a Mapp torch which will have much higher temps compared to the propane. Hotbarrel, do you think the tip for my propane will work for the Mapp bottle too?

Hardening? I have read on this board quite a few opinions about the "best" way to case harden the ejector on the rail. I have also read on various websites different opinions about how to do it. I guess my question is what is the "best" way to do it? How many of you have done this and have not ran into any problems with your ejector wearing out? If you have, what exactly did you do?

Here is the directions on the back of Brownell's Kasenit:

For Mild Steel:
1)Heat part uniformly to a bright red(approximately 1650 degrees F).
2)Dip or roll in compound to form a fused shell around area to be hardened. Reheat to a bright red.
3)Quench immediately in clean, cold water using a scrubbing action to insure maximum cooling rate.

To increase depth,repeat operation No.2 before quenching. To insure maximum of hardness, reheat and repeat operation No.3

For Tool Steel:
Heat part to a light yellow. Deposit in compound and leave until its right tempering heat is reached, then plunge into clean, cold water or oil. This will bring out the utmost limit in hardness and also prevent cracking.

For Deeper Cases on Mild Steel:
Immerse part in compound using open, shallow receptacle. Subject to heat of 1650 deg. F. for a period of from 15 to 60 min, depending upon depth of case required. Use dry tong to remove part from molten compounds.Quench part only in clean, cold water.

First, would I follow the directions for "tool steel"? I have hear others here reference a "Kasenit" from Brownells that is a liquid. Mine is a fine powder. Anyone know anything about this? What have you guys sucessfully used to measure the heat of the metal as you heat it up (visual,welding crayons,magnet)? Here is a link to a similar product that also gives directions on how to harden steel. Click here. Anyone do something similar to these guys?

Last, sorry for ramblin on. I am ready to harden this dam* ejector, but I want to use a proven method for hardening the ejector on a TAPCO like rail. I'm trying not to spin my wheels on this one.....

edit for link to similar thread:http://www.gunco.net/forums/showthread.php?t=704&page=2&pp=10&highlight=harden
 

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Josh,

Anytime you are looking for hardware, this is the place to go.
http://www.mcmaster.com/

The part numbers for the 4-40 bolts are 96710A215 for 18-8 stainless at $4.41 per 50 or 90022A110 for steel at $4.36 per 100.

The nuts are #90730A005 in Stainless at $3.48 per 100 or #90760A005 for steel at $1.38 per 100.
 

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Discussion Starter · #11 ·
7.62x39 said:
Josh,

Anytime you are looking for hardware, this is the place to go.
http://www.mcmaster.com/

The part numbers for the 4-40 bolts are 96710A215 for 18-8 stainless at $4.41 per 50 or 90022A110 for steel at $4.36 per 100.

The nuts are #90730A005 in Stainless at $3.48 per 100 or #90760A005 for steel at $1.38 per 100.
Those really are cheap aren't they. Thanks 762! By the way, would you happen to have a link for ones that are prepainted a dark color or black? Or rather, does McMaster carry ones that are black?
 

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They only offer the 4-40 in 18-8 stainless or mild steel.
If you want them black, get the mild steel and use a black oxide treatment (Brownell's etc.) on them.

I used the stainless ones and just sprayed them with Aluma-Hyde ll along with the rest of the rifle.

Here is a pic of the rail bolted in place.
After bolting them in, the bolts need to be shortened for mag clearance, as you can see in this pic.
 

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Discussion Starter · #13 ·
Once you cut them off, won't it be pretty dificult to get the nut off if you ever needed to disassemble it? Also, do you use something like Loctite to ensure that the nuts don't come off?
 

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yosuthnmasa said:
Once you cut them off, won't it be pretty dificult to get the nut off if you ever needed to disassemble it?
Not as difficult as the alternative, welded. :smile:

Unless you had an ejector wear problem, I can think of no reason why you would want to remove them.
I use red loctite. (271)
 

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Discussion Starter · #17 ·
Guys, I broke out the Propane torch and said what the hell. If it wouldn't get hot enought I'd go out and buy a Mapp/Oxy torch and do it over. Fortunately, I was able to heat it up to a bright cherry red and followed the instructions on the back of Brownell's Kasenit. Rather than dipping it in the Kasenit once, I heated up and dipped it 3 times and then quenched it in cold water. Not thinking ahead of time, I dry fitted the rails and saw that the ejector was too big. I decided to take some material off of the side of the rail that sits on the side of the receiver. This was probably not the best place to do this and I migrated back to the ejector. So, I moved back to the ejector and decided to take the edge of it off so that it would clear the notch in the bolt. Let me tell you something! That ejector was ROCK hard. I couldn't bite into the metal if my life depended on it. I clamped it down and applied as much pressure as I could with a large hand file. The metal just slid over the file like butter. My ejector is really hard! So I took out the trusty dremel and took off more than I think I should've. Couple of questions.

1) how much of the ejector needs to be left to eject the casing properly. I guess what I'm asking is how far into the notch of the bolt does it need to go?

2)do I need to reharden the ejector after removing quite a bit of the edge of it? When I hardened the ejector, did it harden all the way through or just the outside of the metal?

edited for spelling
 

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poor mans kasenit?

josh mentioned something to me about a homemade kasenit that has like, 2 or 3 ingredients in it. anyone ever hear of this stuff or know whats in it? I'm a cheap f, and i got rails that need a hardin'in so it'll be a big help. I hear that the recipe is on gunsnet.net, but i'm no sellout! my allegiance is pledged to gunco! :headspin:
thanks fellas.
 

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yosuthnmasa said:
Will a Propane torch like the one below give me the proper heat to harden my rails using Kasenit from Brownells? Otherwise, what would you guys recommend as a cheap alternative?
I have been heating my rails to a dull cherry red and then quenching them in motor oil until cool. Then I clean them up and put them in my oven at 475 degrees for one hour, turn it off and then leave them in the oven until cool. They come out looking identical to the hardened military rails I have bought in the past. ak'sr4me
 
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