Stationary Ball Screw

Indeed it was the X axis I was thinking about ... apologies for not making it clear. The machine I was pondering was the Steele 4 X 8 router ... he (Steele) discussed assorted methods of driving the X.

1. Rack and Pinion
2. Dual lead screw, Single Stepper, Long Belt
3. Dual Lead Screw, Twin Stepper, Slaved in Mach
4. Dual Lead Screw, Single Stepper, Dual Belt

I was wondering about a single screw 'underslung' down the centre of the X axis but was worried about the Screw sagging and whipping.

I have digested the points raised here and consider all to be valid and helpful. I will return to my planing and thinking with yet more knowledge.

Thank you all for your input.

I am not sure of the one you mean... have you seen the BlackToe 8x4 design - he uses a chain drive...

Oops sorry :redface: I gave bum info it's a 48 X 24 inch machine. http://www.solsylva.com But when I obtained the plans it was called something else .. I was confusing it with the MechMate which I have also been looking at. Too many thoughts at once.

Smiler, If you read this it may clear up the confusion in my PM.

Once again Sorry folks.

Did a search last night and skf are selling a rotating ball screw arrangement, not cheap I bet
http://www.skf.com/portal/skf_us/hom...ntentId=290063
I also recall that someone did a mill conversion to the z-axis where they rotated the ball nut, although I am not sure what the advantage would be in that case.

Peter

Very similar to what the lasers are using today but the Bystronics have the nut inside the servo motor rotor making it a very compact arrangement gives it's a large ball screw and a 7HP motor.

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