rubber or other insert in barrel bore for vibration

Karl_T · Mar 24, 2020

My son purchased this mori seiki lathe last fall
YouTube

Just got it up and running.

He plans to profile and chamber rifle barrels for me. He had heard about inserting rubber or silicone in the barrel bore to help with vibration issues. The cutting will get a long ways from any support and this is a likely issue.

Can anyone comment on this idea or have another suggestion for working on very long L/D rounds in a CNC lathe?

Karl

michiganbuck · Mar 24, 2020

I have never done so but think the plastic wax/ hot dip coating may be good for that.
McMaster-Carr

Also have not run a CNC lathe but if having a spindle bore that runs true one might make a centering device for the barrel end having a probe made for each size/caliber. Tube may be short enough for a spider(?).

ChipSplitter · Mar 24, 2020

I've never done that, but I know there definitely is room for black arts in turning.

Wood does a good job of dampening vibration, too. I had a job one time where I was turning a 6" pipe with a .1" wall. The only way to get rid of harmonics was to use a Garland mallet and press the handle against the OD and the cast head against the X axis saddle. Don't ask me how I did that with the spindle running.

ChipSplitter · Mar 24, 2020

Another idea I had but never tried is to fill a hollow pipe, barrel, etc. with sand. You know how much vibration sand will absorb underneath a concrete pad.... right?

kustomizer · Mar 24, 2020

ChipSplitter said:
I've never done that, but I know there definitely is room for black arts in turning.
Wood does a good job of dampening vibration, too. I had a job one time where I was turning a 6" pipe with a .1" wall. The only way to get rid of harmonics was to use a Garland mallet and press the handle against the OD and the cast head against the X axis saddle. Don't ask me how I did that with the spindle running.

I was making shift levers some years back from 6" to just over 2 feet long out of 5/8 x .188 wall DOM tube. I made something that looked like a heavy duty clothes pin out of a hickory hammer handle with "O" rings on it to keep it tight. It was bolted onto the face of the finish turning tool holder and would rub just a bit at the tool went along. As I recall we would get 25 to 30 levers out of one and then we had to replace it. I kept a few of them soaking in coolant as they seemed to work better when they were about half water logged.

Larry Dickman · Mar 24, 2020

rubber bands can work wonders too

Karl_T · Mar 25, 2020

Thanks for the ideas, will most certainly try the wood suggestion - I've done that with a hammer handle on the 10EE.

Re - rubber bands. can you explain more?

Karl

moonlight machine · Mar 25, 2020

Lead shot in the barrel worked for me. Wood dowel tapped in each end to keep it in.

TeachMePlease · Mar 25, 2020

Karl_T said:
Thanks for the ideas, will most certainly try the wood suggestion - I've done that with a hammer handle on the 10EE.

Re - rubber bands. can you explain more?

Karl

Re: Rubber Bands: I've never had to do it, but I've seen people wrap either the work or the tool holder with lots of rubber bands for vibration damping.

Larry Dickman · Mar 25, 2020

depends obviously on what your doing, but on thin walled parts wrapping a bunch of rubber bands around it will keep it from vibrating.
Back it the old days, when turning brake drums they wrap a rubber belt around the outside to reduce chatter.

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rubber or other insert in barrel bore for vibration

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