Re: [CAD_CAM_EDM_DRO] Ball screw lead

On Mon, 12 Jan 2004 14:30:33 -0000, you wrote:

>What am I missing? I realize the advantage of ball screws is
>the "zero" back lash advantage, (much better than the lead screw in
>my cross slide), however how do you get the incremental movement.
>
>On my lathe the cross slide has a .002 per increment and a 40
>increment dial. This means that the distance in one revolution
>is .080. Most of the ball screws I have found THK for example
>have .500 to .200 lead per revolution. Seems like there is a loss
>in incremental movement.

However, consider what's driving it. If you are driving with a
stepper, directly, and get 400 steps/revolution, you get .500/400 or
about .00125 per step, and that's full stepping, not half or
microstepping.

With .2/step you get 0.0005/step on normal, etc.

While the leadscrew pitch is important, the amount of steps you get
figures into the resolution/step of the actual device.

Harvey

>
>Please help a beginner.
>Thanks and Regards
>James McGuiness
>
>
>
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