Steve Fornelius' Indicator Attachment

“Here's what I made so that I could mount my dial indicator on the headstock arbor. Using this I'm able to get the variance of the milling attachment to less than .001 easily.
The unit is simple to make: Use a blank arbor, drill halfway through with cut down 1/2 inch drill (available at any hardware store. I drilled and tapped a 10-32 hole to take a SHCS. Since you're not turning on the lathe with this in place it isn't important how long the screw is.
For the holder itself, II used a piece of 1/2" 12L14 stock about 3 inches long. I used a 3/8" mill and the milling vice to cut down both sides so the finished size is about 1/4" thick. The reason for this is to allow the dial indicator plunger and dial to clear the holder.I drilled a 1/4" hole in the end.
To use this, mount the dial indicator with 1/4-20 bolt and nut, then slide the holder into the adapter.and tighten down the set screw. Screw the adapter onto the headstock arbor. Put the work piece into the milling vice and move the cross slide down so that the indicator goes around at least once. Crank the cross slide until one side of the work piece is indicating and gently tighten the rear milling adapter screw. Crank to the other side of the work piece and note the difference in readings.
Then I simple twist the milling attachment so that the indicator reads 1/2 the difference. I keep moving the cross slide back and forth, adjusting out the variance until there is no movement of the indicator needle. Then I tighten down both milling attachment screws evenly and recheck the variance. The first couple of times you will probably need to loosen the screws and adjust again, but it works better than any other way I've tried. I can get a repeatable 0.0005 cut on the milled pieces when cutting grooves.”

Guy Zattau's Taig CNC Mill Limit Switches

“Here's some pics of the setup and the limit switch arrangement with no holes drilled in the mill. The white things are the trippers and the run close to the brackets that hold the micro switches.”

Here are the pics of the mill limit switch brackets before being installed. #'s 1, 2, 3 are the X axis that mounts on using the holes for the rubber way protector. It mounts using the two end holes with access holes thru the top for an allen wrench. The rubber is sandwiched in between. The slot is 3/8" by 1/2" and the relief for the post is 3/8". Material is 1 3/4" x 1 3/4" x 6 1/2". I used .080" but it's a little too thick and makes it hard to get the trip levers to actuate the micro switches.

“Z, made from 1" x 2" x 7 1/2" x .058". It is mounted using the holes tapped in the vertical axis post that mounts the power switch. Compression posts made of tubing sleeve the holes. Holes on the part next to the post are clearanced for the screw and the ones on the outside are just big enough for the tubes to pass and finish up flush.”

“the Y axis, made of 1" x 1" x 8" x .058" with two brackets. The brackets are 2" tall with a 1 5/8" foot, 1" x 1 1/2"
wide. The micro switches are approximately 1" x 3/4" x 1/2" and are mounted with 4-40 countersunk screw so the moving parts clear. The trip devices are made of a Teflon like material machined to ride on the moving component just off the surface of the brackets and tripping the actuator lever of the micro switch. It may be necessary to add a piece of shim stock to the lever to make them work, I used .030, glued to the lever with epoxy. “

Here are the pics of the microswitch trip pieces for the mill. The Z is a simple angle piece with a small ramp cut at the top so it can allow the Z axis to go to the limit. X was made as one piece, then cut in half. Drilled the holes first then milled away the sides to leave a ridge. The ridge centers the part and prevents the screws from marring the groove in the table. Cut the 4-40 allen screws to length so they don't bottom against the back of the nut retainer slot in the table. The Y is a piece of work and difficult to get off as it is necessary to remove the microswitch bracket first. The drawing that is enclosed with the copy's I sent you is probably more understandable that what I can write. It's a goofy design but the best I could come up with at the time. All the material I sent you is just meant to be an idea and not an exact blueprint. Everyone should make their own measurements. The main theme was to not drill any holes in the machine, just use the existing ones.