Low frequency reamer chatter

C

chris k

Guest
Guys I have a 17 mach IV reamer that I am haveing a B**** of a time with .It does not matter what rpm , or type of barrel steel or coolant. I've tried holding the reamer by different methods.It always wants to develop low frequency chatter..I think the reamer is ground improperly.I have tried it several times and it is frusterating!!

Any ideas out there???

chris
 
Reamer chatter:

You did not say whose reamer this is, but the first thing to do is send it back to the maker. Failing that, there is an old gunsmith's dodge which really works (I've used it to tame reamers that chattered like a deranged ape): wrap the reamer from the butt to the shoulder in about two wraps of waxed paper - lubricate as usual. This almost always causes the reamer to settle down and ream right, even when the chamber is pretty well advanced and chatter marks are clearly visible on the chamber walls. Since the waxed paper also collects and holds the chips, you might want to withdraw the reamer, clear the chips and re-wrap the reamer frequently. Usually, after the reamer settles down and stops chattering, you can complete the chamber without the waxed paper.
mhb - Mike
 
reamer chatter

Mike ,

I have used that method on reamers that have high frequency chatter and it does work.However it does not with low frequency chatter.

chris
 
Hmmm...

Well, I ream at low RPM, so don't know what constitutes or causes high frequency chatter (the resultant harmonic of necessity being a product of number of flutes/RPM) - I've never encountered a chatter situation that wouldn't submit to the dodge. Good luck!
mhb - Mike
 
I would increase the feed rate, and see if that helps. Pack the flutes with grease may also help eliminate the chatter when you try to continue the cut.
Good luck and let us know how things end.
 
chris k said:
Guys I have a 17 mach IV reamer that I am haveing a B**** of a time with .It does not matter what rpm , or type of barrel steel or coolant. I've tried holding the reamer by different methods.It always wants to develop low frequency chatter..I think the reamer is ground improperly.I have tried it several times and it is frusterating!!

Any ideas out there???

chris
Click to expand...
What is the lathe you are using it on? You report having both low frequency chatter with this reamer and high frequency chatter with other reamers. You may have a spindle bearing problem.

Properly ground reamers normally do not chatter.
 
Reamer Chatter

I has a 22BR reamer that wanted to chatter. I slowed it down to 24 RPMs and the chatter went away. I am assuming the 17 is a pilotless type reamer.
You may find wrapping a few winds of waxed dental floss around the pilot in the direction of turn so it want unwrap will tighten up the pilot and take out the chatter.

Rustystud
 
chatter

JerrySharrett said:
What is the lathe you are using it on? You report having both low frequency chatter with this reamer and high frequency chatter with other reamers. You may have a spindle bearing problem.

Properly ground reamers normally do not chatter.
Click to expand...

It is an English lathe, Colchester , it weighs in at one ton .Very good lathe.Done hundreds of chambers before and several after this chamber job.I think it is the reamer.You misunderstood I have dealt on occasson with high frequency chatter, not all the time .If you do enough chambers you will run into high frequency chatter in your career. it is not an ongoing problem.

I think it is the reamer.

Chris
 
chris k said:
It is an English lathe, Colchester , it weighs in at one ton .Very good lathe.Done hundreds of chambers before and several after this chamber job.I think it is the reamer.You misunderstood I have dealt on occasson with high frequency chatter, not all the time .If you do enough chambers you will run into high frequency chatter in your career. it is not an ongoing problem.

I think it is the reamer.

Chris
Click to expand...

Chris, where are the chatter marks in the chamber area?.........Don
 
chris k said:
It is an English lathe, Colchester , it weighs in at one ton .Very good lathe.Done hundreds of chambers before and several after this chamber job.I think it is the reamer.You misunderstood I have dealt on occasson with high frequency chatter, not all the time .If you do enough chambers you will run into high frequency chatter in your career. it is not an ongoing problem.

I think it is the reamer.

Chris
Click to expand...
Chris, the Colchester is a good lathe if it is in the medium weight class or heavier, but if you are having chatter with more than one reamer you may need a spindle bearing adjustment.
 
Reamer Brands

I absolutely refuse to name names but, when I ream with a certain brand of reamer I always have to be very careful to try to prevent chatter from getting started. I even asked Stick Starks who was the machinist that did most of the chambering at SG&Y, if he had the same experience with Brand X reamers and he verified that he did.

I'm assuming that different reamer makers may grind the leading edge to a different angle but I have no real knowledge of this. I usually use PT&G (Dave Kiff) reamers and have never had one of them chatter on my machine. Dave's reamers give a good finish to the chamber but the Brand X reamers give an almost polished finish to the chamber when not chattering.

I recently chambered a 30PPC for a customer using his new Brand X reamer. That sucker started chattering almost immediately. I removed the reamer and went back in the hole with a Kiff 6PPC reamer and then switched back to the Brand X 30PPC just before finishing the chamber. The chamber turned out real well after all of that but it did make me work to get it right. I know.... the pilot was useless on the 6PPC reamer but I taper bore the chamber so the reamer ran true even without the pilot touching.

Shelley
 
spindle bearing

Thanks for the info.

I beleive it is the reamer,

Jerry how do I check and adjust a spindle bearing as I have never done this ?

thanks ,
chris
 
chris k said:
Thanks for the info.

I beleive it is the reamer,

Jerry how do I check and adjust a spindle bearing as I have never done this ?

thanks ,
chris
Click to expand...
There may be an on-line Colchester manual on spindle bearing adjustment. If not go to one of the amature machinist sites and get someone who has a Colchester manual to send you a copy.
 
You may have too much overhang of the barrel out of the chuck if you are chambering in the headstock.
If you are chambering on the three point steady then you could have similar problem . Move the barrel toward the chuck a bit more and it may dampen the frequency.
Also make sure the lathe is level and sitting rigid and that the motor is rubber isolated from the lathe bed.
 
This may have nothing to do with your problem. But when turning I was getting a pattern on what I was turning . And was told to mount the motor on rubber and that salved my problem. I never chambered a barrel before I put rubber motor mounts on the lathe so I don't know if that would have been a problem or not.
Art
 
I think it is the reamer as well. If the reamer has too much clearance at the margin it might show this tendency. A reamer which is made with insufficient negative rake might as well (it's a fine line).
What you describe as low frequency chatter, I understand to be almost a grab/ release cycle as the positively raked cutting edges dig in, bottom out on the margin, then release. Reducing the margin clearance (will reduce reamer diameter. Be careful) might turn the trick. Regards, Bill.
 
reamers

Of all the reamers I have this 17 mach IV and years ago a 300 H&H reamer are the only I have had trouble with. The 300 was a grind problem.

I am going to send the Mach IV back .
Chris
 
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