Some milling machine goodness happened this weekend!
I was able to finish two of the hand-wheel interfaces for the stepper motors:
This time I decided to make the whole interface on the milling machine instead of using the lathe. I started with a 20mm thick piece of steel stock and milled it down to 15mm.
Once I had the shape milled out, I flipped the piece over and drilled out 3 holes at 120° and threaded them to mount the timing gear to (I love my rotary table!).
Here's a comparison of the two pieces. The one on the right is the one I completed this weekend. It's not as thick as the one on the left as the acme shaft-end that I'm mounting the stepper motor (and timing gears) to doesn't protrude as far out.
I drilled out and countersunk machine bolts on the aluminum timing gears and mounted them to the interfaces for the hand-wheels. The one on the left is assembled.
It's getting so close now I can taste it! Here's a test-fit of the thinner of the two interfaces.
And a close-up shot.
Here's a mock-up of the stepper motor mount on the y-axis with the hand-wheel and my interface in place.
Another shot - envision the ruler as the timing belt connecting the stepper motor to the y-axis acme screw. Once I have the alignment done, I'll fabricate tin covers for the drive train to protect the belt and timing gears from chips.
Some good progress made today in the continued conversion of my milling machine to a CNC machine using Dave Rigotti's kit from Hobby CNC.
I've been working on a way of interfacing the stepper motors via an engineered belt (also known as a timing belt) to the existing hand wheels used to move the table.
I've come up with a replacement part that will allow me to mount the driven cog to the acme screws of the milling machine. Click on the images for a larger view.
I started with 2 1/2 inch diameter steel stock
Bored out the correct size hole for the acme lead screw shaft
Turned part of the interface to the right diameter to fit the hand wheel's teeth
Set it up on the milling machine to mill out the interfacing teeth
And voila! The part I made is on the left. The handwheel is on the right. You can see how the two mesh together.
Bringing the two parts together.
The fit is perfect!
I placed the timing gear on top of the interface part I made to give you an idea of its function. The timing gear will be attached to the interface part which will in turn (pardon the pun ) drive the acme lead screw.