[QuinnSjoblom]

The other day I had this idea and I'm curious if anyone has tried it. I have a 3 axis cnc with a 2.2kw spindle. I need some small aluminum posts, 6mm at the largest diameter, 40mm long. I was thinking maybe I can chuck some 6mm aluminum rod in my er collet and turn it like a lathe. Cutting tool would be secured in my vice stationary and the turning part on the spindle would move along z and x axis. Assuming I can wrap my head around the cam, should this work? Anyone try it?

[ger21]

Like this?
https://www.youtube.com/watch?v=hvw7Kagk0o4

I don't think the 2.2kw spindle has enough torque at low speeds.

[QuinnSjoblom]

Yes! exactly like that. for what im trying to do, i think it could work. Just needs to be really small diameter to be in the right rpm range and have enough torque. I might give it a try. Pretty easy to tell if the spindle isnt happy so ill be ready to back it off. But yeah, in that video they had 5/8 stock which would definately put me at too much sfm and not enough torque at 6k, but with 1/4 stock, i think i would be within acceptable numbers

[awerby]

That could go spectacularly wrong in a millisecond. Those spindles run much faster than a lathe, and without support on the far end of your aluminum rod, the potential for disaster is real and present. What happens when the rod decides to bend a little?

[deadlykitten]

of course, it may work there are cnc's built on this idea ( check link below )

if you wish, use a hidraulic collet with peripheral cooling, so to grab nice the aluminium rod

also, if rpm is high, use a gears attachement ( ratio 1:5, 1:10, etc ) so to multiply the rpm output by the spindle, so to avoid spindle stress at high rpms

https://www.youtube.com/watch?time_c...&v=2tRieVsx2T8

[deadlykitten]

... and don't forget to put the tools on the 4th axis i can speed up that setup, by using low clearances ( 1.5mm ) and multiple safe-positions

... the potential for disaster is real and present

this is life

[deadlykitten]

forget the CAM

... steal a lathe program from the forum
... modify preparatory codes
... X coordinates : = X coordinates / 2 ; this may not deliver the G03/G02s , so better activate an X scale = 0.5 ( if your controller has this function )

kindly

[JohnHaine]

CNC Milling Machine as a Lathe

[QuinnSjoblom]

That could go spectacularly wrong in a millisecond. Those spindles run much faster than a lathe, and without support on the far end of your aluminum rod, the potential for disaster is real and present. What happens when the rod decides to bend a little?

You make it sound like running a lathe without a tail stock is unheard of. It's pretty common isn't it? Obviously a tail stock is needed for very long skinny parts, but if kept within limits, it should really be no different from doing it in a lathe as far as the risks of not using tail stock.

As for rpm being higher than a lathe, yes I realize my rpm range is less than optimal, but for the optimal sfm on 1/4 inch stock, I'm within the correct range