Reamer marks in chamber

Discussion in 'Advanced Gunsmithing & Engineering' started by Cloudrepair, Oct 21, 2017.

  1. Cloudrepair

    Cloudrepair Gold $$ Contributor

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    Ok I've chambered a few barrels now and have had great results.
    Now I got a bore scope and see they are great except for some marks in the neck and free bore. From what I can tell is they must be from the time I stopped the lathe to pull the reamer out for the last time
    And it tight and not so easy to take strait out.
    So how do you guys finish and take your reamer out without this issue.
    It seams to be just cosmetic and not do any harm.
     
  2. Joe Wade

    Joe Wade

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    What kind of markings in the necks and free-bore are you getting?
    Your last few cuts should be very light ones, only removing about .005" for finish passes.
    Also, the way you remove the reamer is important. After stopping the lathe, I gently twist the reamer in a cutting direction (clockwise) and back out. Never turn a reamer backwards.
    Also, watch the size and shape of your chips when roughing. If your chips are large enough to curl, you are feeding too fast for the RPM you are running and will leave ring marks in the body of chamber. You can run a reamer too slow rpm. I have better results around 150-170rpms for chambering. For threading, I like the slowest setting the lathe will go, around 75 rpm.
     
  3. Cloudrepair

    Cloudrepair Gold $$ Contributor

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    Maybe I'm just to impatient and take to big of cut at the last .02 or so
    The marks are parallel to bore and only in the neck and free bore
     
  4. Hal

    Hal

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    If the marks are parallel to the bore, your pulling the reamer straight out. Turn the reamer clockwise as you pull the reamer out of the chamber.
    Hal
     
  5. Cloudrepair

    Cloudrepair Gold $$ Contributor

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    Yes that I think is the the problem the top pic is the worst one I have found.
    Top and bottom are same
     

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    Last edited: Oct 22, 2017
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  6. X Ring Accuracy

    X Ring Accuracy Site $$ Sponsor

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    I will put my flame suit on now......Pull the reamer out of the chamber when final depth is reached while spindle is still running. Not going to argue this as I haven't the patience but it is machining 101
     
  7. Cloudrepair

    Cloudrepair Gold $$ Contributor

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    Thanks
    That would be my first thought only I'm using a hand held unit right now
    And I'm blind in one eye and have no depth perception so I may pull it strait into one of the sides and there goes my chamber I just got to that point.
    Maybe I need to try and find a floating reamer holder I like again.
    So far I didn't like the first two very much.:(
     
    Last edited: Oct 24, 2017
  8. butchlambert

    butchlambert Site $$ Sponsor

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    Don't argue with me then.
     
  9. kendog

    kendog

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    Sell the bore scope on Ebay, and the problem will magically disappear. ;)
     
  10. Cloudrepair

    Cloudrepair Gold $$ Contributor

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    I know but I will try not to drive you all nuts with questions.
    I am a machinist and do know what to do. I like to hear what you guys have to say though
    reaming a barrel isn't a common thing In a job shop eather.
    I was well prepared for it though and have no problem getting things dialed in quick.:D
     
  11. Rustystud

    Rustystud Site $$ Sponsor

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    I have cut a few chambers over the last 45plus years. It is my suggestion that a reamer never be inserted or removed from a non rotating barrel. The reamer can an will cut lines parallel to the bore every time. A second tip is to never turn a reamer or the chuck backward to the cutting edge of the reamer (reverse). Reamers are engineered to cut in one direction with relief behind the cutting edge, if turned in the opposite direction they can load quickly and overcome the strength of the reamer causing it to break. Just my two cents worth.
    Nat Lambeth
     
    Last edited: Oct 26, 2017
  12. Ggmac

    Ggmac

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    Like rustystud says . I remove my reamers out 1/2" as the machine is rotating to a stop after the power has been turned off . Feed the last few cuts slow . After the machine is off I completely remove the reamer . I've had no problems this way . Once removed 1/2" or so , no cutting /scratching takes place . You still need to be careful when removing it the rest of the way , but that's easy .
     
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  13. Tim Singleton

    Tim Singleton Gold $$ Contributor

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    One of the best barrels I ever chambered left a few lines on the cases :)
     
  14. Ksracer

    Ksracer

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    Just curious. If you're NOT using a flush system and you pull the reamer out under power, is there any chance a chip could get wedged under a flute after the cutting edges open up from the chamber and leave a score mark?
     
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  15. Tim Singleton

    Tim Singleton Gold $$ Contributor

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    Sure will
     
  16. Will Henry

    Will Henry

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    I always pull the reamer out with the lathe turning. Last cut is generally about .020" and is fed in very slowly. The face of each flute is cleaned with a ceramic stone before the last cut. Very straight cases are more likely to cause a problem than are cases with some taper. WH
     
  17. TRA

    TRA Gold $$ Contributor

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    On final cut, clean all chips and apply plenty of oil to the reamer.

    With say .002 left to cut, push reamer against the stop, dwell for a few seconds with tension pushing the reamer in, and shut the spindle off, hold pressure on reamer until the spindle stops. When the spindle stops then you retract the reamer. Pull it straight out, no twisting, turning, or with spindle under power.

    There is no plus from removing a reamer while it's turning.
     
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  18. butchlambert

    butchlambert Site $$ Sponsor

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    Pulling it out while the spindle is turning increases the chance of a chip putting a ring in the chamber.
     
  19. AndyA

    AndyA

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    I always hone the chamber with some 400 grit paper on a dremel at low speed to remove any marks.
     
  20. sean68

    sean68 Silver $$ Contributor

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    I don't use a flush system and I have a lot more success stopping the spindle first and then removing the reamer. I don't get lines in my chambers. Like Butch mentions, it's easy to catch a chip removing it on a rotating spindle. There are many ways to do these sort of things and subtle differences in technique can mean the difference between success and failure no matter which option you choose.
     
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