barrel question. Could a ss barrel be too hard to ream????
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srhaggerty
Well-Known Member
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410 found in like Krieger barrels are this type of steel
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Kreiger offers 410 ss upon request; all other barrels are 416 ss /ubbthreads/images/graemlins/wink.gif
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I apologize for the false information. The website is not real easy to read. It looks like they use 416R also. I guess I never said they use it all the time /ubbthreads/images/graemlins/laugh.gif ....
[ QUOTE ]
410 found in like Krieger barrels are this type of steel
[/ QUOTE ]
Kreiger offers 410 ss upon request; all other barrels are 416 ss /ubbthreads/images/graemlins/wink.gif
[/ QUOTE ]
I apologize for the false information. The website is not real easy to read. It looks like they use 416R also. I guess I never said they use it all the time /ubbthreads/images/graemlins/laugh.gif ....
wapiti13
Well-Known Member
Krieger uses 410 SS in all barrels shorter than 27" with a contour below #5. 416 SS used on #5 contours and above. Just for the record. /ubbthreads/images/graemlins/shocked.gif
I have never chambered a barrel, but i have done a lot of machining of stainless steel and i do know that the surface can become VERY hard from a tool that rubs without cutting fresh material or a tool that loses lubrication for even a brief moment.
My approach when machining stainless is to keep the tool cutting fresh material at all times. As the tool cuts the stock, the material in contact with the tool is placed under presure and the surface wor hardens. The next pass of the tool must always be enough to cut through the hardened skin. once you stop the feed, the spring effect between the tool and work would cause the tool to rub against this hard skin and your tool dies instantly. the next pass would create more friction(the tool is more blunt than before) and the surface is harder and thicker than it was and it just get worse from there.
If you now take a new tool and attempt to attack this hard skin, you have to attack it with a lot of positive feed to get it through the skin as quickly as possible and hopefully have some tool left by the time you are cutting fresh material again.
I would imagine that with a chamber reamer you have a very long cutting edge and this would require a lot of pressure to get it cutting and then keep it cutting. I for one would not like to be the one taking a fresh reamer to a work hardened chamber.
It would be interesting to see what did cause your problem.
PS. i once found an inclusion in a 3" diametre 316 bar that was so hard that it finished coated carbide inserts as soon as the carbide touched it. the inclusion was almost like a piece of rock or ceramic
My approach when machining stainless is to keep the tool cutting fresh material at all times. As the tool cuts the stock, the material in contact with the tool is placed under presure and the surface wor hardens. The next pass of the tool must always be enough to cut through the hardened skin. once you stop the feed, the spring effect between the tool and work would cause the tool to rub against this hard skin and your tool dies instantly. the next pass would create more friction(the tool is more blunt than before) and the surface is harder and thicker than it was and it just get worse from there.
If you now take a new tool and attempt to attack this hard skin, you have to attack it with a lot of positive feed to get it through the skin as quickly as possible and hopefully have some tool left by the time you are cutting fresh material again.
I would imagine that with a chamber reamer you have a very long cutting edge and this would require a lot of pressure to get it cutting and then keep it cutting. I for one would not like to be the one taking a fresh reamer to a work hardened chamber.
It would be interesting to see what did cause your problem.
PS. i once found an inclusion in a 3" diametre 316 bar that was so hard that it finished coated carbide inserts as soon as the carbide touched it. the inclusion was almost like a piece of rock or ceramic
J E Custom
Well-Known Member
Fortunately I have never broken a reamer (Knock on wood) and hope I never do.
I use nothing but finishing reamers and I have to take it easy and feed .030 to .050
thousandths depending on the size of the reamer (Smaller reamers will load up faster)
so less is better.
On reamers like the 17 HMR I could only feed .010 to .015 thousandths.
Material does make a difference and the worst that I know of to chamber is 17-4-PH.
I have seen tight bore barrels and if the pilot is to big it will cause problems.
If your smith broke 2 reamers in the same barrel the wrong pilot dia. or technique would
be my guess, And it is just a guess!!!
J E CUSTOM
I use nothing but finishing reamers and I have to take it easy and feed .030 to .050
thousandths depending on the size of the reamer (Smaller reamers will load up faster)
so less is better.
On reamers like the 17 HMR I could only feed .010 to .015 thousandths.
Material does make a difference and the worst that I know of to chamber is 17-4-PH.
I have seen tight bore barrels and if the pilot is to big it will cause problems.
If your smith broke 2 reamers in the same barrel the wrong pilot dia. or technique would
be my guess, And it is just a guess!!!
J E CUSTOM
Fiftydriver
Official LRH Sponsor
Did this problem ever have a resolution?
Not knowing the RPMs and feed rate, it makes it very hard to say what could have caused this problem.
Let us know what came of the problem, that was nearly 4 years ago.
Not knowing the RPMs and feed rate, it makes it very hard to say what could have caused this problem.
Let us know what came of the problem, that was nearly 4 years ago.
J E Custom
Well-Known Member
**** I not only type slow (That is what BB said) I also read slow. 2005 ? wow.
J E CUSTOM
B Jordan
Well-Known Member
he sent the barrel back in and the company chambered it i forgot what he told me for sure but i know that they used a differant setup than the normal lathe setup
im not oldfamily but i did know the fellow that chambered the barrel (died about a year ago)he was a machinist and gunsmith for 45-50 years and built several hundred rifles around here and was a very smart man i remember him saying he would never buy another barrel from this company also he was very carefull and Meticulous i believe he told me that was the only time he ever broke a reamer
Fiftydriver
Official LRH Sponsor
i would almost bet money they used a solid carbide chambering reamer to do that barrel if it was that hard.
Why not offer the name of the barrel maker? Some barrels are just harder then others and it may help some avoid a similar problem. I know its not your barrel but just curious what barrel it was. Sounds like a Lother Walters to me or a Black Star.
THanks for the update.
Why not offer the name of the barrel maker? Some barrels are just harder then others and it may help some avoid a similar problem. I know its not your barrel but just curious what barrel it was. Sounds like a Lother Walters to me or a Black Star.
THanks for the update.
B Jordan
Well-Known Member
the barrel was a shilen dont know if it was cm or ss
Fiftydriver
Official LRH Sponsor
That is odd for a shilen, espeically if stainless but as many barrels as they put out a year, its unrealistic to think that a barrel with an issue could not get out the shop door.
