Retracting reamer at end of push

[INTJ]

How? Reamers/chambers are tapered.
Chip weld can and will cause rings in the chamber. Sometimes it's so small you need magnification to see it until you learn what to look for.

Does ringing the chamber have anything to do with whether the spindle is stopped or not when withdrawing the reamer?

 

[Greg Y]

Stall with a welded chip....it's gonna leave a mark.

 

[DaveTooley]

Does ringing the chamber have anything to do with whether the spindle is stopped or not when withdrawing the reamer?

If you have chip weld, and we all will to some degree, it will leave a ring in the chamber. It may be a faint ring but it's there. It may survive a light polishing of the chamber and transfer to the cartridge case. Other than making the phone ring it doesn't cause any problems. Just part of the machining process. On the other hand catching a chip under a flute during the final pass is for sure going to make the phone ring if it's on the body. Does it affect functionality? Depends.
Regardless of whether you stop the spindle to withdraw the reamer you should always back off some as soon as you hit tour number. In, pause for a split second, then back off. I cringe thinking about what is happening to the reamer in contact with the barrel and not cutting.

 

[Carl S]

Does ringing the chamber have anything to do with whether the spindle is stopped or not when withdrawing the reamer?

I don't load the reamer to much when approaching the finished number..keep the flutes empty. also keeping the cutting oil flowing helps to minimise the chance of a chip rolling.

 

[INTJ]

Cool. That's how I do it. Slowly approach my final number, and immediately back off as soon as I reach it. No one taught me that, it just seemed like a good idea. I also use the flush for the final pass even if it's only a couple thousands.

 

[Lucky Shooter]

I think I'm the enemy with my problems.

I suspect every barrel I've ever done over the last
several years has transverse scratches on the land tops in the leade.

I didn't know about this until I got a borescope----two
barrels ago. Two different reamers for 221 FB and 22 PPC
have the same scratches.

When I reach the end of a push, the reamer holder is firmly held
back against the face of the floating pusher. The tailstock quill is
backed off a bit and the tailstock is slid backward. The chuck is still
turning.

The barrel and reamer are thoroughly cleared of chips before the
next push.

After locking the tailstock and lubing the reamer and hole the next
push is started from about .020" short of the end of the previous push.
There is a very minor amount of torque on the reamer handle until
the reamer reaches the end of the last push and then the cycle repeats.

These scratches don't seem to have a great effect on accuracy nor copper
fouling. I need to learn how to properly start a push and to retract----please
don't read anything else into this post. We're still talking rifle barrels.

Please make this idiot proof for me.

A. Weldy

Stall with a welded chip....it's gonna leave a mark.

 

[Greg Y]

I run an indicator on my tailstock. I typically make .050" pushes. When I hit my number I stop feeding and let the reamer rotate with the barrel. Lathe stops, and I snap the reamer backwards and check for chips/clean it.

My next push will start +/- a thou or two from where I left off every single time. I rapid in to about 10 thou out, then creep in till I make contact and make my feed. (How fast I feed is assessed through the barrel. Some cut like butter, some are more stubborn. Some reams will tolerate less rpm....some will chatter like mad spun slow).

Regardless, I try to make my final pass close to 10 thou. It gives me a good feel on the tool with minimal worry about chip load.

 

[Rustystud]

I have seen a lot of advice here, I have cut thousands of chambers over the last 50 years. I never stop the lathe when chambering. While turnig I back off on the hand wheel enough to bring the reamer from contacting the chamber. I have in the past let the lathe stop the withdraw the reamer and in make length wise cuts in the chamber wall. Since I have never stopped the lathe with a reamer engaged.