How to re-mount turned parts without damaging them?

[Decs0105]

Time for a beginner question...

How do you guys re-mount parts when you finished off one side? I always struggle to do that. I mean I always try to do as much operations as possible without remounting a part but for example when done your part and cut it off you still have a side that needs a facing operation to look perfect...

I tried to protect it with tape but that doesn't work if I tighten the chuck properly and it is not really good for the accuracy... and mostly using aluminium doesn't help either

Any tips would be really appreciated, thanks guys!

[cinqster]

I just use ordinary 1/2" vinyl insulation tape. If I need a thinner strip I'll cut it down on a cutting board. I also cut the tape length to match the circumference of the piece, so there's no overlap. Sometimes it's a mm or two short so I make sure the gap is not under the chuck jaws. I've found that if you very carefully do the chuck up the alloy won't mark as the work often doesn't need to be mounted that tightly. To my surprise the work normally centres up really nicely, it's only when the piece is overtightened that the tape compresses too much and things go horribly wrong.

This week I found some soft jaws available for small chucks - anyone use them, and are they any good?

[gionc]

So:



0.3 o 0.5 mm brass foil. BTW I have to be honest: it's the first time I turned both front and back sides.

[p9o1r1sche]

I have made a split ring to hold a part in when remounting. I turn a ring with the inside diameter within 0.003" of the outside diameter of the part. Then cut through the side of it (parallel to the axis) with a saw so it can grip the part enough for turning. This can also work if you dont have enough surface to put in the chuck jaws. The ring distributes the clamping force over a wide enough area to avoid marks. I hope this is clear enough for you to understand. Unfortunately, I dont have any pics at the moment.

[gionc]

Originally Posted by p9o1r1sche

I have made a split ring to hold a part in when remounting. I turn a ring with the inside diameter within 0.003" of the outside diameter of the part. Then cut through the side of it (parallel to the axis) with a saw so it can grip the part enough for turning. This can also work if you dont have enough surface to put in the chuck jaws. The ring distributes the clamping force over a wide enough area to avoid marks. I hope this is clear enough for you to understand. Unfortunately, I dont have any pics at the moment.

Great idea.

[cinqster]

Gerry Wingrove wrote a section on making split collets for wheels etc. in one his books.

[Decs0105]

Originally Posted by gionc

Great idea.

yes indeed!!!

Thanks for your help guys. Now I only need some time to try all these things

[gionc]

Originally Posted by Thesaint111

yes indeed!!!

Thanks for your help guys. Now I only need some time to try all these things

This is also a super cool idea to mount small diam. or thin hex pipes: I wondered to use a mini chuck (something like the dremel chuck, the auto-centering one) to do it but a set of rings (or better pipes) help better (and chaper)

[bobss396]

I try to avoid holding finished parts in steel chuck jaws. If you can, use collets for everything, they won't mark up the parts if they're burr free and kept clean. I've used brass shim stock in the past when I had to hold a finished surface in a 3-jaw chuck.

Bob