SpudFiles

(Mods feel free to move this if this should belong elsewhere)

Ok, I've got to know how you do it. As a challenge to myself I decided to forgo my lathe and attempt an O-ring cut using just my drill press. The guides and the cuts are easily attempted using machinist files, however, due to the play (back and forth motion) of the piston, my cuts aren't even slightly precise. I end up with cuts shallow on one side and perfect on the other.

I have mad respect for anyone attempting this. Any advice would be appreciated.

Just file down the shallow parts by hand. Use a fine file and check the depth every like 10 passes or so. You should get it to pretty tight tolerances if you are careful.

Have you ever tried using an extra long carriage bolt so that you could run one end into the chuck, pass through the piston, and then into a drilled end cap (the end cap being mounted in a vise on the press table)? I think this may balance the rotation a bit.

Yes. Is that like your other mind relpying to yourself?

Lol, I've done this successfuly with a dremel for making groves for orings in small scale robots and such to use as wheels. Never tried with a drill press how ever I never noticed play in a press, would your's happen to be a piece of shit?

well, our drill press has a hole in the stand just big enough to fit a washer snuggly in it. I figure if I wanted to I could turn ours into a "lathe" by puting a bolt on top and bottom with the top in the chuck and the bottom having the washer fit in this hole.

Well, it's not play in the spindle so-to-speak, its the fact that one end of the piston is secure and the other is not. So when turning at high speeds it wobbles.

That's the thing, the washer fits so snuggly it can't wobble at all. I haven't tried yet, but it should work in theory.

The issue is most likely not that it's acctualy "wobbling" - but simply that it's not stuck on there perfectly strait.
And yeah, the chucked end won't deviate from it's center very much... I believe the term "run out" is used when refering to this attribute in a mill, and it'll be around a few thousandths of an inch.

Carefull turning between centers - what squeaks suggested - will help if you manage to chuck it properly, or if you manage to drill an exactly centered hole in the opposite end.

If you need everything to be exactly cocentric, you could machine it from oversize starting materials. This might be difficult to do without a proper lathe, but I can't tell you, as I've never done it.

I get what your saying boilingleadbath. Finding the exact center shouldn't be that hard though if you know how to use a compass.

Turn at a low speed!

SpudStuff, and why would that be?

Less wobble. I've tried that as well. I've got an extra drill chuck around and maybe I can use it. Damn, you guys who do this without a lathe are my heroes. I've built my own lathe (Gingery) and I can figure out you guys do it.

Update: Using an extra long hex bolt and a lockout washer I've stabilized it. I also used a sawzall blade to cut the o-rings and have had a very definite success. An aside, I hate T-pistons, coaxials are so much cleaner looking.

Cool! Good job can't wait to see the finished piston!