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Reaming tips

NewGunPlumber

Aluminum
Joined
Dec 18, 2019
Hi all,

Getting very close to having everything ready to cut my first chamber. This will be set up through the headstock with inboard and outboard spiders, chamber flush system running around 45psi and 1gal / min of ridgid dark cutting fluid flow with adjustment on both pressure and flow, have the ability to stop fluid and do high pressure air flush as needed. Have piloted reamers, reamer stop and PTG floating reamer holder to be held in the tailstock.

Haven't decided 100% if I'll pre drill then parallel or taper bore. Makes sense just depends on if I get frustrated setting up the compound to correct angle etc!

So keeping the above in mind I'm reasonably confident with the turning and threading part of the process BUT I've never had another job that has required using a reamer in a similar way so looking for some advice. My main questions or concerns are around plunging the reamer

Speeds. Everyone seems to have a different theory but sounds like around 100-150 with front flush and reasonably ridgid setup is going to be close and manageable starting point?

Stopping and restarting. Again read some different opinions on this. My concerns with running a floating reamer holder is if I withdraw or plunge the reamer into / out of contact while the barrel is turning there is enough movement in the reamer holder for the reamer to grab and bounce around inside that clearance damaging the chamber. The other theory seems to be maintain pressure on the reamer so that it has full contact until the barrel has stopped turning. To me one has the potential to damage the chamber and one has the potential to damage the reamer. What's everyone's thoughts?

Depth of cut. Having front flush SHOULD be clearing chips. The more the reamer is removed and reinserted the more potential there is for problem as per point 2. For those using similar setups what do you find works? First chamber will be a 308 and I know different diameter and length reamers will all effect this but some guidelines would be good.
 
With the flush system, you don't need to fully remove the reamer from the chamber to clear chips. Just back it out roughly half the length of the pilot. This way the pilot is still supporting the reamer and the flush system will push out the chips. I keep my left hand on the reamer holder when going in and out of the chamber to keep the reamer centered and from sagging.
 
Hi NewGunPlumber:
Have you considered answering these questions for yourself by chambering a bunch of scrap material first, before you do a customer's gun?
Find out what steel the barrel is made of, get a short bar (or get an old beater worn out barrel), drill, bore, and ream a hole the proper size and then chamber it using your setup.
If all goes well you know what to do.
If it does not, at least you haven't destroyed a perfectly good barrel.

Cheers

Marcus
Implant Mechanix • Design & Innovation > HOME
Vancouver Wire EDM -- Wire EDM Machining
 
Ok sounds good. Even if I have to fully withdraw the reamer to inspect the chamber your saying the pilot is going to support / align it well enough with a little assistance to prevent sag.

I've read of others are pre drilling and taper boring and don't use a pilot at all. Apparently helps increase cutting fluid flow and if the hole is bored straight to the indicated throat then the reamer isn't being miss directed along the way. Makes sense in concept but looses the function of the pilot.

Implmex I won't be doing any work for others. Problem with scrap stock is there isn't a bore and groves for a pilot to run in and cutting fluid to pass around so nothing is really going to simulate a barrel that well. I have a used barrel that has potential to shoot very well with a cut back if done correctly. If not down correctly it will require a new barrel so where possible I'd like to get it rite the first time
 
Set your compound angle before chucking up the barrel.
Set you chamber reamer between centers.
Put your boring bar toolpost on your compound and with your indicator and magnetic base. With the indicator running on reamer set the compound to run parallel with the reamer.

Hal
 
Set your compound angle before chucking up the barrel.
Set you chamber reamer between centers.
Put your boring bar toolpost on your compound and with your indicator and magnetic base. With the indicator running on reamer set the compound to run parallel with the reamer.

Hal

If you do this, make damn sure you are running the indicator dead center on the check piece. Any deviation up or down will introduce an error to your measurement and you will set the wrong angle.
 
Look at your reamer print. Note the diameter difference between the shoulder/body junction and body diameter at the .200” datum. Not a whole lot of difference, is it? On a manual lathe, taper boring is a waste of time vs. just parallel boring, in my honest opinion. For me, it’s just numbers, and my programming time and cycle time is the same be it tapered to match the chamber body or just parallel.
 








 
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