buck futter
ArboristSite Guru
How do you hold a piston in a lathe to cut a pop up with very low run out? Looking for pictures please.
Thank you in advance
David
Thank you in advance
David
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chadihman
Addicted to ArboristSite
I drilled and tapped a piece of round stock that fits in the piston boss were the connecting rod pin goes. I then drilled a hole in a square plate I place the piston on the square plate and thread a bolt through the plate and into the round stock. Then I adjust my four jaw chuck.
Boleclimber
ArboristSite Guru
I put one wrap of masking tape on the piston then clamp it in a 3 jaw chuck.
machinisttx
Addicted to ArboristSite
If I were just doing one, I'd wrap it with masking tape or use shim stock between it and the jaws(4 jaw or set-tru 3 jaw). If I were running a bunch of them the same, I'd cut a set of soft jaws.
An independent 4 jaw or set-tru 3 jaw are the only easy ways to get low runout. There are probably some lathes with a collet attachment big enough, but I'd imagine the collets very uncommon....I haven't seen one that big. If all you have is a regular, non adjustable, three jaw and it's running out a lot, you can shim one jaw or a combination of jaws. Otherwise you'll have to bore a set of soft jaws. There is one other option, but I'd be hesitant to use it. You can improvise a four jaw with a piece of pipe and some bolts or capscrews. It's a ghetto fabulous solution, but it can work. I had to do this once to crown and thread an AK pistol barrel. Be sure to use some brass or aluminum shim stock between the screws and the part though.
An independent 4 jaw or set-tru 3 jaw are the only easy ways to get low runout. There are probably some lathes with a collet attachment big enough, but I'd imagine the collets very uncommon....I haven't seen one that big. If all you have is a regular, non adjustable, three jaw and it's running out a lot, you can shim one jaw or a combination of jaws. Otherwise you'll have to bore a set of soft jaws. There is one other option, but I'd be hesitant to use it. You can improvise a four jaw with a piece of pipe and some bolts or capscrews. It's a ghetto fabulous solution, but it can work. I had to do this once to crown and thread an AK pistol barrel. Be sure to use some brass or aluminum shim stock between the screws and the part though.
buck futter
ArboristSite Guru
Thanks guys.
Today we chucked up a piston in a 3 jaw lathe and no matter what we had about 5 thou run out we got it to about three thou after a bunch of fiddling. I have set up before with what you have shown. I didn't know if there was an easier way. I think the skirt taproom was fn us.
David
Today we chucked up a piston in a 3 jaw lathe and no matter what we had about 5 thou run out we got it to about three thou after a bunch of fiddling. I have set up before with what you have shown. I didn't know if there was an easier way. I think the skirt taproom was fn us.
David
