Ever since Chuck Fellows posted the original article, I have been working on this. My inability to get much shop time in has made it take so long, but now it is to a point where I can post my progress.
Originally, I started to make both the rotary table and this version, and I ordered a 4-inch rotary table from Grizzly which turned out to be so non-ridgid as to make the rotary table version a dead end for now, although I might revisit it at some point.
I chose a spindexer as the basis for the unit as I have a selection of 5C collets and one thing I often do is use them with collet blocks to make 4-sided and hex ends on rods and get tired of indexing with the blocks, especially if my setup is somewhat tricky.
Before doing much else, I machined a key slot in the base parallel to the shaft and then carefully machined off the base casting to provide a way to also mount the entire assembly in my mill vise. I may never use the key slot, but at least it is there if I want to.
The next step was a piece of 0.25 aluminum, which was repeatedly modified as the project proceeded. It is a little rough, but I see this as a usable experiment rather than a bling contender.
I made things easier on myself by using Chuck's original drive ratio, choosing a timing belt and pulleys from McMaster-Carr (Usual disclaimer: No ties to them).
To avoid milling or drilling the spindexer shaft, a taper lock was made for the shaft drive pulley, although I later found out that the motor had enough torque make things slip and I decided to add a 0.125 key to keep things locked up.
I also used Chuck's version of the Arduino, Chuck's driver board, and Chuck's keyboard shield. I added sealed momentary switches and connected them in parallel to the switches on the keyboard shield, and just drilled a hole to allow using the reset switch with a paper clip or somesuch. I found few reasons to need reset, and fewer buttons simplifies the panel. The circuitry is mounted in a diecast aluminum box, and a piece of 0.25 plexiglass is milled to fit into a milled-out window in the box to see the display.
A separate power supply can be placed somewhere away from chips and coolant and saves having to cook up an elaborate enclosure. A modified square electrical box provides for enclosing the AC connections and also holds a separate 9-volt supply for the Arduino and other circuit boards. The motor power supply is 12-volts, which is adequate for this use. The red neon indicator signifies AC input to the box. The green indicator signifies the 12-volt supply is on. Connection to the control box is with 4-conductor cable, 2 conductors for each power supply. I used the square 4-conductor connectors to make sure that connections are never confused.
I find the indexing works well enough for my use. I did need to experiment with the numbers of steps just a little, but most problems were due to mechanical slippage or to electrical crosstalk during the breadboard stage. Once everything was buttoned up and enclosed it settled down.
https://youtu.be/B60SzUv1BEw
I still have a little bit of fiddling to do, cleaning up dykem and etc. I bought the Arduino experimenter kit and have another Arduino now and another driver board, so I may do some more experimenting.
, so I have to be as low as possible with the spindle.
