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Rockwell scale

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I know one LRB reciever tested at 35 rockwell to soft needs to be in the mid 40s to mid 50s to constitute a good hardness for a reciever, right. Is there such a thing as to high of a rating let say 60 rockwell. Is too hard of a rating bad and why.
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Steve, where did you hear of a LRB being to soft? I think if they are to hard on the scale, they become brittle, and are prone to cracking easier. I don't know the number though. I am sure someone with more knowledge will chime in. I am interested to know abbout the soft receiver though. I thought all were tested before shipping?
 

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Howdy Steve k:

You're right.To soft is not good and to hard is just as bad.To hard is prone to crack and shatter,somewhat like glass does.

I think a good range would be about 48-54 on the rockwell.
As long as a part is not heat treated in the 400-450 degree range as this will and does cause imbrittlement problems.
HTH

warbird out
 

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Redbone wrote:
Steve, where did you hear of a LRB being to soft? I think if they are to hard on the scale, they become brittle, and are prone to cracking easier. I don't know the number though. I am sure someone with more knowledge will chime in. I am interested to know abbout the soft receiver though. I thought all were tested before shipping?
Redbone Bill at Smith Enterprise while going over my LRB reciever stated that they test one LRB reciever at 34 rockwell. They couldnt lap becasue it was too soft. I guess it is like any thing else you buy these days a bad apple makes it through QC once in a while. My wife bought a new 2003 Duramax Chevy pick up. The day after she bought it the transmition went out :evil: I dont think it is anything to worry about since he also stated that the rest test high 40s to low 50s. I would imagine this has had to of happened before with other make of recievers.
 

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Steve .....

I was pretty heavily involved when my friend introduced his milled steel receivers for the AK47 ....

His are 45 Rockwell and one that is too high would then be too brittle .....

I've always been under the impression that 42-52 is a general ballpark figure that would be suitable but I could be wrong. I do know that if it is too high they can become very brittle .....

Six
 

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Does anyone know what Rockwell scale is being used to determine the hardness of these receivers. Is it Rockwell "C"? The "C" scale uses a diamond point and is the one usually used for tool steels. As I look at the indentions on my Garand bolts (my M1As are in North Carolina :wink: ) I would speculate that the diameter of the indention is too large for the "C" scale.
A Buck knife would be in the mid 50s on the "C" scale, a Kabar would be in the mid to high 40s. The Buck takes longer to sharpen than the Kabar because it is harder, but it will hold it's edge longer than the Kabar.
I also am not sure if a receiver is hardened through and through or just the exposed surfaces. Does anyone know what kind of steel is used?
 

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Hillbilly: From what I've read, yes - it's the Rockwell "C" scale.

The indentations on the bolts are not hardness test marks. They are proof marks to show that the bolt was test fired with a "hot" round during acceptance testing by the Government.
 

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It is my understanding that a Rockwell test of 60 is at the upper limit. I also remember that it was reported that ArmsCorp receivers were at 60 for hardness and considered by some to be at the max limit.

Regards

Ox
 
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