Crossfeed drive

[Evan]

Thanks David,

Perhaps we can swap. I have two HP pen plotters, eight color with lots of spare pens. The electrostatic hold down is dead on both but otherwise they work fine. I made an IEEE488 adapter to run them from the parallel port and modified the machine language code to accomodate these super high speed CPUs but have some glitches. Some timing problems. Anyway, If you have an IEEE488 HPIB card I am interested. E-mail me.

[Bruce Griffing]

Another thought on the crossfeed drive. I have a homemade x axis feed on my minimill that uses a small gear head motor connected via a toothed belt. Without power feed, it is a little hard to crank the x-axis as you are moving the table and the motor through the gear head, but it is not bad. This turns out not to be a problem since the feed is so convenient to use I use it all the time. The interesting thing I discovered about this arrangment is that I can set the speed control for the motor so it doesn't move on its own, but provides a power assist for hand cranking (in one direction). Sorta like power steering. I actually use that mode. Between full power mode and power assist, I don't use the unpowered hand crank for anything but fine adjustments. A similar setup might be nice on your lathe.

[This message has been edited by Bruce Griffing (edited 10-13-2003).]

[Oso]

How about this:
A slot in the end of the screw (I know, no mill, but there are other ways...)with a drilled out center area. For the hole, extend the existing center hole, which you probably will never need again, as the screw won't need to be re-cut.

Then the drive for crossfeed is a shaft to fit the hole, with a pin through it to fit the slot.

Retract the shaft to disengage the feed.

The pin could be made of brass or copper etc so it will release (break) on an over-torque situation.

Depending on relative fits, it could act as a U-joint to allow some misalignment. A ball-shaped end to the shaft would help that.

[nheng]

Oso: I kinda like that idea and may try it on my smaller machine. I've got a tiny Swiss minimotor with gearhead (485:1) waiting to go !
Den