Protect part while turning

[CraigLD]

What is the go-to method for protecting the finish on a small part when turning it in a lathe. This is mainly when you already worked on one end and then have to flip it in the chuck to work on the other end. I've seen suggestions such as wrapping it in the think aluminum from a cut up soda can, or wrapping it in some thin leather. But hoping some of you long time experts have some better ideas. Perhaps even some method that is reusable.

As always, thanks in advance.

 

[minh-thanh]

CraigLD !
I often use soda cans when working with brass and iron, and use soda cans and paperboard with aluminum
with reuse: and with a fixed diameter size, I usually use aluminum tubes or brass with a suitable diameter or I will make it fit then cut one side of the tube ( That's the way I do it, but I'm not an expert )
hope this helps .

 

[tornitore45]

I have accumulated a box of split tubes collars. Any kind of tube I ever had, water pipes, copper pipes, aluminum pipes, patio umbrella, dismantled appliances etc.
Rarely I can't find or resize one that need to make a new one.
Even if it is not the right size, saw a wider gap and the chuck jaws will shape it to fit.
For small diameter just bore a slug and when you are done put in a plastic bag and write the size or the thread. I have 2 dozens hanged on a spike sorted by size. Soon enough you accumulate all the usual sizes.

 

[almega]

For small parts, once turned round on one end, I chuck the finished end in a ER32 collet fitted to the head stock of my lathe. The collet doesn't damage the part and the part runs true without having to recenter like if the 3 or 4 jaw chuck is slightly off center. The only caveat is that the sizes have to be close to the collet sizes I have but that is usually not a problem. Before the ER32, I would make a small collet in the 3 jaw chuck to the size of the turned end and use that to be sure it ran true when turned around to work on the other end. For larger parts, I use thin aluminum wrapped aroung the chuck jaws to protect the work.

 

[Badhippie]

I personally use brass shim stock .010 - .025 works the best for me.

 

[CraigLD]

So many great suggestions, thanks everyone.

 

[stevehuckss396]

If standard size it's hard to beat a collet. If it's a weird size I just wrap 2 layers of printer paper around the part and put it in a chuck

 

[almega]

If standard size it's hard to beat a collet. If it's a weird size I just wrap 2 layers of printer paper around the part and put it in a chuck

I have done the same thing with aluminum foil and that works good, too. There are a lot of ways to skin this cat and it never ceases to amaze me what the accummulated knowledge of this forum has to offer. Awesome!

 

[petertha]

Its hard to beat the simplicity & disposable expense of tape. It is actually amazingly consistent thickness & you have one side with a bit of adhesion. I use masking tape all the time for ordinary parts. Usually a single layer is fine & will show no jaw depression to the part, or double up if warranted. Its not like you are going to gronk tighten something delicate anyways. Just align the tape gap to a space between jaws so each jaw sees the same thickness add.

On more continuous holding fixtures like collet chucks or jigs, I use film tape. Its generally thinner than masking tape but again, very consistent thickness if centering is an issue. (Why I would avoid thick, squishy materials). I have some aluminum tape which I think is hardware stuff used for ducting or similar.

The only downside is some cutting fluids can break down the adhesive & its a bit gooey. But its usually for a one time operation & easlyremoved with any common solvent.

 

[tornitore45]

If something a bit thicker than soda cans is desired, aluminum flashing is readily available and inexpensive.

 

[Wizard69]

I've had good luck with plastic shim stock. Very easy to cut and if you have too, to free up a hand it can be held in place with tape. The nice thing here is that plastic shim stock can be had in "books" that have "pages" of various thickness which comes in handy around the shop. So buying a book of plastic shim isn't a waste of money.

The other material that I've had good luck with is copper pipe either as a sleeve or smashed flat to form a shim. This is stuff is nice because I have scrap from plumbing jobs and stuff left over from my fathers business. In some cases you may need to anneal the copper. Copper seems to grip a bit better too.

What you should avoid in my opinion is anything compressible, that as a result might loosen under load. Having a piece shift in a chuck is bad voodoo. Thus I would stay away from wood, leather, soft plastics and the like.

You can also consider super glue or maybe Loctite and piece fitted chucks. For example, if you need a machine the other side of a custom washer, machine a pocket in some waste stock and then glue the washer into the pocket. Heat allows for separation after machining and a little clean up and you are done. Clean up can be done with super glue solvents so as to avoid surface damage. This technique can be extended to a lot of different items, the only thing you need to be concerned about is run out. Well that and really heavy cuts might not be a good idea.