Reamer Wear

R

Redmist

Guest
This may sound like a stupid question, but at what point do you decide a reamer requires a re-grind?

I am just in the process of chambering my first barrel, (yes I am a total beginner) all is going well and I am half way into making a new chamber (7mm/270WSM)

The reamer has been used only a couple of times before and I know the previous oner treated it right as it produced a couple of match winning barrels.

Now, I am cutting only .040" at every pass, removing the reamer, cleaning off the swarf and using high grade cutting fluid, but not in a flush system set up. I am turning the handwheel on the tailstock really slowly so I get even pressure on my reamer holder on my fingers so I dont think I am overloading the reamer.

Here's the problem (it may not be a problem)

I cut .040", I let the reamer holder go, stop the lathe, slide the tailstock out the way and rotate the reamer clockwise and gently pull out at the same time.

The reamer moves back but seems to "stick" just a little. When I do remove the reamer out the chamber, I see fine swarf in the neck area bettween the floating pilot and free bore area and fine ribbon swarf between the flutes.

However, I notice that from the shoulder back by distance of about .350" there are very fine particles just beneath the cutting area of the flutes over 360 degrees of the total cutting area of this section of the reamer.

I suppose the question is - is this normal?

The cutting process appears to be going very smoothly and I am not rushing with feed rate or spindle speed (150rpm)

Oh in case of anyone wanting further details the barrel is a Broughton, chamber is running at 3/10ths runout on what I have cut so far, and its a Bald Eagle reamer holder.

Thanks in advance. I can post pictures if required - as I say, it may not even be a problem!
 
The way (if I understand it right) you'r describing cutting the chamber is the hardway. The better method is to remove as much of the chamber material as possible (within 0.1-0.15mm of final diameter dimensions and 0.5mm body length dimensions) by carefully using a single point tool and use the finishing reamer just for the job to finish.
The reamer will cut better and last much longer.

Shoot well
Peter
 
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Don't stop the lathe when pulling the reamer back. Once I begin to chamber I don't stop the lathe at all.
 
Jim, you just have to be quick. ;) I wouldn't expect a rank ammature to know how us eggspurts do thangs. Mickey (AKA 'Nub')
 
Guys thanks for the replies.

I considered boring out the chamber, but (again could be dumb question) if I do this, what stops the reamer running off as the pilot isnt engaged in the lands untill the last part of the process.

Would it not be more accurate to bore out partially - just enough so that the pilot still engages with the rifling, then ream a little and bore out some more etc?

As a rank amatuer, I dont understand how I can accurately measure the final headspacing measurement with the lathe spinning at 150 rpm?

Thanks for the assistance.
 
Redmist said:
Guys thanks for the replies.

I considered boring out the chamber, but (again could be dumb question) if I do this, what stops the reamer running off as the pilot isnt engaged in the lands untill the last part of the process.

Would it not be more accurate to bore out partially - just enough so that the pilot still engages with the rifling, then ream a little and bore out some more etc?

As a rank amatuer, I dont understand how I can accurately measure the final headspacing measurement with the lathe spinning at 150 rpm?

Thanks for the assistance.
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This should cover your limited experience:
Play safe.
If you drill about 0.5mm smaller than is the catridge shoulder diameter to the depth about 1.5mm short of the final depth and than bore out the 1/3-1/2 front of the hole slightly that should be enough for the pilot to engage into the bore. If you know how to set on the taper its even better. Because you can bore the entire hole on the correct taper, but below the final dimension.
Use a screw locked collar on the reamer set to 0.5-1mm short of the final depth.
When the reamer cuts on the shoulders it's not too sensitive to go any deeper than is the push/force behind it.
Use an indicator for the final headspacing.

You can go much closer (within 0.1-0.15mm) with the (pre finish) tolerances if you feel confident enough, as I play here deliberately on generously safe side.
If you have an old barrel have a practice run 1st.

Shoot well
Peter
 
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Redmist said:
Guys thanks for the replies.

I considered boring out the chamber, but (again could be dumb question) if I do this, what stops the reamer running off as the pilot isnt engaged in the lands untill the last part of the process.

Would it not be more accurate to bore out partially - just enough so that the pilot still engages with the rifling, then ream a little and bore out some more etc?

As a rank amatuer, I dont understand how I can accurately measure the final headspacing measurement with the lathe spinning at 150 rpm?

Thanks for the assistance.
Click to expand...
Of course you have to shut the lathe off to measure headspace. :) Jim was just jabbing at me because I said that I never shut the lathe off when obviously you have to.

I don't prebore my chambers, though. I have some reamers that I have cut over 50 chambers with and they're still good. I only use finish reamers. There's nothing wrong with drilling/boring a lot of the metal away but I use a flush system when chambering and just use the reamer.
 
Redmist -

You say you're feeding the reamer in with the tailstock handwheel "very slowly" - someone correct me if I'm off-base here, but feeding it in too slowly could tend to be counterproductive, and may even dull the reamer prematurely.

But then, I'm looking at reamer feedrate from the perspective of someone who uses a drill to rough the chamber (very similar to the way Peter described), and then bores the drilled hole true to within .015"-.020" of the finished chamber dia. at the shoulder before ever using the finish reamer. Since I began using this method, my finished chambers very seldom have more than a couple of tenths runout.
 
Mr Coleman

I was using sarcasm by way of reply - I will keep my fingers and stop the chuck before final measuring, I never intended to do otherwise:D

Guys thanks for the advice it really has been helpful and I do understand - I guess you all use a system / method that works and stick to it.

I believe I am feeding the reamer at the right rate as it "feels" like its cutting (I have pretty constant pressure on the fingers holding the reamer holder) and I dont let up on the feed on the handwheel untill I have made a .040" pass, then I let go the reamer and stop the lathe.

I just wondered about the very fine particles really just beneath the cutting edge of the flutes as they were different to the ribbon swarf that was passing out of the chamber onto the bed.

You have all been most helpful, accept my apologies for being dumb.
 
Reamer regrinds

I use a flush system with Rustlick 255R cut 5:1. I run 15 gallons of coolant at 10-125 psi dependent on reamer, and speed. I have a PT&G 95 palma finish reamer that has cut over 300 chambers. MY PT&G 6mmBR reamer has well over 200 chambers cut with it. My 6mmBRX and Dasher reamers have over 50 chambers on each. When I was reaming the old school ream and clean I would have to regrind/sharpen about every 25-30 chambers.
Rustystud
 
Redmist said:
Mr Coleman

I was using sarcasm by way of reply - I will keep my fingers and stop the chuck before final measuring, I never intended to do otherwise:D

Guys thanks for the advice it really has been helpful and I do understand - I guess you all use a system / method that works and stick to it.

I believe I am feeding the reamer at the right rate as it "feels" like its cutting (I have pretty constant pressure on the fingers holding the reamer holder) and I dont let up on the feed on the handwheel untill I have made a .040" pass, then I let go the reamer and stop the lathe.

I just wondered about the very fine particles really just beneath the cutting edge of the flutes as they were different to the ribbon swarf that was passing out of the chamber onto the bed.

You have all been most helpful, accept my apologies for being dumb.
Click to expand...
I run into people not catching my offbeat sense of humor all the time. No offense taken here at all.

I would recommend unlocking the tailstock and pulling it back while the lathe is turning. THEN you can stop it and clean whatever you normally do. What speed are you using to ream? I ream at 260 rpm but I've heard of others who run faster.
 
As far as your reamer pulling out hard, I would make sure your pilot bushing is not TOO snug. It's quite easy to drive a too snug bushing into the bore with the tailstock wheel. It's another thing to pull it out. I once had the same problem, I checked the bushing in the bore then drilled and bored the chamber, started reaming, and had sticky extraction of the reamer. cleaned it up and slid it in by hand. Yep grab the next smaller bushing.
 
Jim

that was my problem, I went to the next size down and everything worked out just fine.

First attempt appears to be a success, I am waiting for a stock from Mr Shehane, then I will see if the thing shoots!
 
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