Rotary Table CNCing

[irving2008]

Well the machining of the stepper mount has taken a back seat for a while due to the weather - it being too cold to work out in the garage (and I've had a cold too). So I decided to buy a PIC programmer with the original intention of using Kwackers software and a 16F452 PIC but then I decided I wanted the stepper driver to be built in, not a seperate board and, hey ho, I like writing code. So I knocked up a quick breadboard using a 16F877 I had lying around and wrote a fledgling set of routines to read the keyboard, drive the display, create stepper pulses, etc. At the moment this is driving my L297/298 stepper board, but I have some IRF520 logic level MOSFETS and I plan to drive the stepper directly in Unipolar mode with a chopper current limiter. I have a ex-laptop 24v 65W (2A+) power supply that is perfect for the job. The PIC and display take less than 60mA so a straight 7805 regulator on a small heatsink will provide the 5v rail.

[Robin Hewitt]

I was looking at sintered bushes with a view to taking a .375" ID .6" OD bush, opening out to 10mmID and turning it down to 15mm OD.

Sintered bushes come oversize and go to size when you drive them home. I did try machining one once and it was distinctly odd, they are a bugger to chuck and smear rather than cut