Chambering issue - flutes loading up uneven

[Rich S]

Well starting my winter projects and was doing a practice chamber on an old barrel. All went pretty good except the reamer appears to be mainly cutting with one flute. The flutes for the neck appear to be loading even but 1 of the shoulder/body flutes is loading up significantly more than the others. The reamer seemed to cut very smooth with no chatter. Due to the one flute loading up I had to take small cuts ~0.005" to keep from scoring the chamber. I pretty much just did this on the last 6 cuts.

For my set up I was using a Bald Eagle floating reamer. The barrel was indicated in the head stock to within 2 tenths using the Gordy method. I pre-bored (drilled followed by boring bar) ~0.7 deep and left 0.050" diameter to cut. In addition to using the floating reamer holder I tried: turn it by hand and cut ~0.010" once the chamber was 50% complete, rotated the reamer (handle on floating reamer holder) 180 deg and used a reamer wrench and a dead center in the tail stock instead of the floating reamer holder to push the reamer. These resulted in the same results with the one (same) flute loading up. The only way I was able to get the other flutes to load up was be increasing the rate the reamer was pushed in. Although the other flutes did pick up some material, the one was still loading much more.

Since it was the same flute regardless of method or orientation loading up, my assumption is the the leading edge on the shoulder of that flute is slightly proud of the others. I don't see anything obviously wrong visually, no defects felt with the fingernail, not build up on the reamer, ect... This was a used reamer given to me but should have only been used for one other reamer. My initial thought is to send it out to be re-sharpened/checked. Any thoughts on this would be appreciated.

 

[GNERGY]

I rented a 375 Ultra mag reamer that cut on every other flute ( of the 6 flutes 3 cut the chamber, got all the chips ) It was brand new and cut the chamber perfectly, no chatter. I marked the flutes with a sharpie when I sent it back and let them know.
Did the chamber come out to be in spec. ( not larger at the base ) then you're good to go. If you plan on using it more then maybe get it resharpened.
Tarey

 

[hogpatrol]

Tailstocks are notoriously off center or angled to the headstock axis. I've set up new lathes that they were off in both orientations. I wouldn't use a tailstock with a hard setup to do a chambering job UNLESS it was dead nuts to the headstock. YMMV.

 

[JRS]

Sounds like the typical PT&G reamer

 

[Eddie Harren]

Sounds like the typical PT&G reamer

"A bucket doesn't stink until you stir it!"

 

[Rich S]

Tailstocks are notoriously off center or angled to the headstock axis. I've set up new lathes that they were off in both orientations. I wouldn't use a tailstock with a hard setup to do a chambering job UNLESS it was dead nuts to the headstock. YMMV.

I thought alignment issues could contribute to what I was seeing although I was using a floating reamer holder. However if it was an alignment issue I would think it would show up at the same orientation with respect to the lathe. Instead, it followed the flute on the reamer. I clocked the reamer in multiple orientations and it always followed the same flute. I also tried to apply a light side pressure just to see what would happen. Same results. I doubt my tailstock is set up accurate enough for a hard setup but gave it a try pushing with a dead center to see if there was any change. I took one 0.025" deep cut. This was just a practice chamber so I was more interested in figuring out the issue than creating a per spec chamber.
Thanks
Rich

 

[hogpatrol]

I know I just cautioned about tailstocks but you could try putting the reamer shank in a lathe, collet setup, with the neck/freebore end in a live center and use an indicator to see if that one flute is high. Then try it without the tailstock.

 

[Rich S]

I rented a 375 Ultra mag reamer that cut on every other flute ( of the 6 flutes 3 cut the chamber, got all the chips ) It was brand new and cut the chamber perfectly, no chatter. I marked the flutes with a sharpie when I sent it back and let them know.
Did the chamber come out to be in spec. ( not larger at the base ) then you're good to go. If you plan on using it more then maybe get it resharpened.
Tarey

Tarey,

I didn't measure the chamber but suspect it is to spec. or at least matches the reamer. After reaming I inserted the reamer and there was no detectable play indicating an oversized chamber. I also checked runout several times as I was concerned the uneven loading could cause the reamer to go off center. The finished runout from the chamber to the bore was less than 2 tenths with the chamber being basically 0. With the borescope the chamber looked decent and the throat looked even. This was just a practice chamber. I figured I'd send the reamer out to be resharpened before I do the barrel I intend to use. That was part of the reason for this post. I was looking for some feedback before sending it out.
Thanks
Rich

 

[shortgrass]

Tarey,

I didn't measure the chamber but suspect it is to spec. or at least matches the reamer. After reaming I inserted the reamer and there was no detectable play indicating an oversized chamber. I also checked runout several times as I was concerned the uneven loading could cause the reamer to go off center. The finished runout from the chamber to the bore was less than 2 tenths with the chamber being basically 0. With the borescope the chamber looked decent and the throat looked even. This was just a practice chamber. I figured I'd send the reamer out to be resharpened before I do the barrel I intend to use. That was part of the reason for this post. I was looking for some feedback before sending it out.
Thanks
Rich

Manson does a very good job of re-sharpening with a very reasonable turn-around time. Call before shipping the reamer.

 

[savagedasher]

We have several tool grinding shops in our area . Take them the print of the reamer and they will make the same as the print . Your are shouldn't be any different. Larry

 

[shortgrass]

I've spent many hours in front of tool and cutter grinders (with my hands on the wheels). I don't believe I'd let anyone who isn't thoughly familiar with chambering reamers sharpen one. They've got their own quirks. The reamer makers are set-up to properly hold and index chambering reamers for grinding. It'd take more time for an experienced tool grinder to set-up to grind a chambering reamer than it'd take a reamer maker to actually do it! It ain't like sharpening a chucking reamer.

 

[savagedasher]

I've spent many hours in front of tool and cutter grinders (with my hands on the wheels). I don't believe I'd let anyone who isn't thoughly familiar with chambering reamers sharpen one. They've got their own quirks. The reamer makers are set-up to properly hold and index chambering reamers for grinding. It'd take more time for an experienced tool grinder to set-up to grind a chambering reamer than it'd take a reamer maker to actually do it! It ain't like sharpening a chucking reamer.

All the ones I know sharpen from a computer generated grinders that why they needing the prints Larry

 

[gat]

Not that unusual in my experience. If your chamber measures to specs why worry.

 

[shortgrass]

All the ones I know sharpen from a computer generated grinders that why they needing the prints Larry

Then you don't know half of what you think you know, do you. Manson does re-sharpening and alterations on manual T&C grinders. I'd not be surprised if others do, too. A couple of years ago I called Hart barrels to place an order. Jim Hart answered the phone as Karen was chit chattin' on another line. Jim and I had a decent conversation where I learned, among other things, that he still makes his rifling buttons on a manual T & C grinder. A lot more still comes off of manual T & C grinders than what you'd think. The chamber reamer makers have work holding for the tools they make/alter/sharpen. It doesn't matter if the machine is a CNC or a manual, you still have to be able to hold, properly, whatever you're machining/grinding. Just because the machine is CNC controlled doesn't need mean you can ignore that fact. The reamer makers have the proper fixtures. The work with the same tooling every day. They know the particulars of the tools they make/alter/sharpen. CNC doesn't cure everything,, not even stupid. But, I'd suppose you could sharpen a chambering reamer with your Dremel tool, couldn't you Larry? Why would anyone put up with a tool that has 6 cutting edges where only one edge was doing the cutting?

 

[savagedasher]

Then you don't know half of what you think you know, do you. Manson does re-sharpening and alterations on manual T&C grinders. I'd not be surprised if others do, too. A couple of years ago I called Hart barrels to place an order. Jim Hart answered the phone as Karen was chit chattin' on another line. Jim and I had a decent conversation where I learned, among other things, that he still makes his rifling buttons on a manual T & C grinder. A lot more still comes off of manual T & C grinders than what you'd think. The chamber reamer makers have work holding for the tools they make/alter/sharpen. It doesn't matter if the machine is a CNC or a manual, you still have to be able to hold, properly, whatever you're machining/grinding. Just because the machine is CNC controlled doesn't need mean you can ignore that fact. The reamer makers have the proper fixtures. The work with the same tooling every day. They know the particulars of the tools they make/alter/sharpen. CNC doesn't cure everything,, not even stupid. But, I'd suppose you could sharpen a chambering reamer with your Dremel tool, couldn't you Larry? Why would anyone put up with a tool that has 6 cutting edges where only one edge was doing the cutting?

When you sharpen a tool you only make it under size . With a tapered chamber die ever thing must be moved back . That can't be done without a print . I would think the one flute was slightly over size .
Merry Christmas to you Larry

 

[shortgrass]

When you sharpen a tool you only make it under size . With a tapered chamber die ever thing must be moved back . That can't be done without a print . I would think the one flute was slightly over size .
Merry Christmas to you Larry

Well,,, state the obvious! One flute is longer than the others! And ya', even a reamer maker who's re-sharpening uses a print. He, also, uses the info acid etched on the shank of the reamer (neck diameter, throat angle, free bore length). I'd call a "sharpen" job to be a one-off. We're not talking about sharpening a hand full of drills or chucking reamers here. With all the variations guys want in reamers anymore, re-sharpening would be on a one on one basis. Regardless of the current notion, there is NO microphone on that CNC machine that you'd just talk into, telling it what you want, and I'd doubt that CNC T&C grinders have "conversational programing",, which means they use G code. Takes time to write a program, so it'd have to be a complicated part to justify writing a program for a one-off. It'd probably cost at least twice as much to have a local tool grinding shop (is there such a thing? almost everything comes out of a little plastic box, anymore) sharpen the reamer as it would to send it to a reamer maker to begin with, if they'd even agree to do it!

 

[dmoran]

Have no clue for the most part of what all reamer mfg's do in the making of a reamer. Just know that I will always desire an "experienced hand" at reamer grinding to make and/or regrind mine. Can't help but think the guy who makes reamers every day would be the most qualified and who I will desire.
Donovan

 

[savagedasher]

Well,,, state the obvious! One flute is longer than the others! And ya', even a reamer maker who's re-sharpening uses a print. He, also, uses the info acid etched on the shank of the reamer (neck diameter, throat angle, free bore length). I'd call a "sharpen" job to be a one-off. We're not talking about sharpening a hand full of drills or chucking reamers here. With all the variations guys want in reamers anymore, re-sharpening would be on a one on one basis. Regardless of the current notion, there is NO microphone on that CNC machine that you'd just talk into, telling it what you want, and I'd doubt that CNC T&C grinders have "conversational programing",, which means they use G code. Takes time to write a program, so it'd have to be a complicated part to justify writing a program for a one-off. It'd probably cost at least twice as much to have a local tool grinding shop (is there such a thing? almost everything comes out of a little plastic box, anymore) sharpen the reamer as it would to send it to a reamer maker to begin with, if they'd even agree to do it!

Mine charges about 2/3 the cost of a new reamer same as the reamer company does No shipping and one day service and if I want a change it don't matter . And this special tool things as you call them the are centers Bless your heart. Larry

 

[Riesel]

Hmmm...................as soon as that "one cutting flute" wears down a little you'll have a new sharp reamer.

 

[Riesel]

Hmmm...................as soon as that "one cutting flute" wears down a little you'll have a new sharp reamer.