Lathe & Workpiece Question

[Splat]

Today I was thinking about my first project I'd do when I finally get my first lathe. (any day now, any day :bitingnails It got me wondering about distance between centers and how would I hold the work in the lathe.

The work pieces in question (let's call them arms) are part of a drummer's boom cymbal stand. Each is composed of 2024 aluminum rod of 0.5" diameter with the rods attached to a round "head". I have about 10 of these arms and the rods on some are about 17" long and others are roughly 22". FWIW the round "head" at the end is about 1.25" diameter. Here's some pics of one of the arms:



I'm wondering how would I hold this piece on the lathe to knurl the rod. Would I put the round head in a 4-way chuck with the rod supported with a rest or the other way around with the rod in a chuck or collet with the rod passing thru a rest and let the round head spin freely? Thank you.

 

[Splat]

How much of it do you want to knurl? If it's only a few inches of the end, I'd just stick the shaft through the headstock and have at it. If you want to do the whole piece or your headstock is too big, you will probably find that holding the funny shaped end in a chuck is your best bet. You would need to support the outboard end either with a center in the tailstock or a steady rest.

Oops! I forgot to state ....I'd be knurling 1" from the end to about 1"-2" from the round head. I'd like to get a lathe with 1" or more spindle hole. If I run the rod thru the spindle it would have to be held with a collet or a chuck or....?

 

[Tom Griffin]

To knurl long, slender shafts like that you'll need to used one of the clamp type knurling tools. Otherwise it'll be too difficult to get a consistent knurl over the length of the shaft. This type of knurling tool is also a lot easier on your lathe because it won't push against the workpiece.



Tom

 

[Splat]

Thanks guys. So just for clarification please, pieces like this with a TOL of 23.5" I could do in a 10x22 lathe if I passed the rod into the spindle a hair?

 

[Tom Griffin]

Thanks guys. So just for clarification please, pieces like this with a TOL of 23.5" I could do in a 10x22 lathe if I passed the rod into the spindle a hair?

It will be close.

The 22 refers to 22" between centers. A chuck will eat up a few inches of that so you would need to use a collet to hold the rod. You also may not get enough travel out of the carriage to knurl the entire rod in one pass.

Tom