Chambering reamer question

D

Dennis Sorensen

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Have any of you guys had an 06 size or magnum size chambering reamer that when cutting the last .300 - .400" of the chamber, the last part - largest diameter of the reamer would seem to burnish the chamber and be extremely hard to remove the reamer from the chamber... if the rear of the chamber was lightly polished then the reamer would be free... it is as if the relief has not been ground enough when the reamer was made? When this happens it is extremely hard to hold on to the reamer with a 4 inch 'dog' while turning at 45 to 60 rpm... and it is very hard to get the reamer out... and it is not the pilot - it is the rear of the chamber...

I have had a few new reamers do this... I have to stop and lightly polish the body, ream some more, polish, ream, until completed. The chambers end up just fine.

It has to be the relief or I should say lack of relief on the flutes...???

I am waiting for a reply from the maker.

Dennis
 
Dennis I often have the same problem, but was afraid to ask. Only on the long reamers/chambers. Its almost like the metal is work hardening. Even when proboring and drilling. I use the method of using indicator rods to set up barrels. I at one time thought that it may be runout past the point where the barrel was indicated in the lathe causing a tight spot. I am curious as well what others have to say.
 
I have encountered this only in the last few years... prior to that the only similar problem occurred with a 17 Remington reamer that was only ground round... no relief at all and I did not notice that until the reamer stopped solid in the barrel about 3/4's chambered. I had to drive the reamer out from the muzzle... The maker re-ground the reamer with back relief and it cut beautifully...that was about 1972.. that's why I suspect the problem I have today is not enough back relief ground in the reamer. It has occurred with several different quality stainless barrels... I don't think the barrel is 'work' hardening...
 
I wonder if this may also have something to do with the metal. Most metals have a range of acceptable alloy content which can either run at the low end, or the high. For example although 304 is considered harder to machine, there are more machinable versions available which tend to lessen the content of those elements which allow it to work harden easily, and stress those which allow it to better respond to machine work. If that is the case, it could more or less be a contributing factor along with tool geometry.
 
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Hi Dennis,
I also have had this problem, 30 - 06 and a stainless steel barrel,
but in my case the problem was solved with a better quality cutting oil.

Valdimar.
 
I have had a couple reamers do that from the same reamer maker. On close inspection, it appeared that the final stoning was done at a too flat angle. In other words, the stoning had dulled the reamer flutes. If it appears that the flutes have a wide stoning mark, this may be the culprit. The maker and myself couldn't understand how this can happen as the reamer is held in a fixture to assure the angle is correct but I think it has to do with excess stoning.
After a trip back to the maker the stoning marks were much thinner and the reamers cut just fine.
Gene
 
I was talking to Dave Kiff today, he called about a past inquiry I had made. It seems in the last few years barrel makers have been sourcing different suppliers of steel... some of these steels have different characteristics and require reamers ground with less margin on the body. In effect sharper than previously ground for the older steels.

PTG will regrind their reamers with a finer margin, all the reamers they are now manufacturing are being ground with a very small margin... about 1 thou instead of about 5 thou if I remember correctly.

In the past reamers were not ground with this small margin, as they would tend to chatter easily with the older barrel steels...
 
Dennis Sorensen said:
Have any of you guys had an 06 size or magnum size chambering reamer that when cutting the last .300 - .400" of the chamber, the last part - largest diameter of the reamer would seem to burnish the chamber and be extremely hard to remove the reamer from the chamber... if the rear of the chamber was lightly polished then the reamer would be free... it is as if the relief has not been ground enough when the reamer was made? When this happens it is extremely hard to hold on to the reamer with a 4 inch 'dog' while turning at 45 to 60 rpm... and it is very hard to get the reamer out... and it is not the pilot - it is the rear of the chamber...

I have had a few new reamers do this... I have to stop and lightly polish the body, ream some more, polish, ream, until completed. The chambers end up just fine.

It has to be the relief or I should say lack of relief on the flutes...???

I am waiting for a reply from the maker.

Dennis
Click to expand...

Hi Dennis,

Without wanting to start an argument, how are you setting up the barrel for chambering?

I have found this probelm with 'reamer bind' on longer chambers when i used to chamber all my barrels between centers. Usually not an issue with this method provided the bores are fairly straight (or straight-ish), but when you encounter a barrel where the bore is obviously not 'optically straight' you are going to have problems, especially if you have a fairly closely fitted pilot. You can sometimes get away with it on short little chamber reamers, but on the long or magnum cartridges if your set-up is not good for that particular barrel, then you will have problems for sure.

Since using the Gordy Gritters-type method through the headstock to chamber those non-straight bored barrel blanks, especially for big chambers, i have had no issues with the reamer wanting to fight with me while chambering. Also alwasy have nice concentric throats.

Of course it could be something else to do with the reamer as well, or a problem with the barrel steel. Another good reason to go to a flushing system on your chambering lathes. I wouldn't chamber without it now.

Dean.
 
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