Using the mill to mill the mill

The installation of a one-shot oiling system requires distribution grooves be cut into the saddle and the head ways. Unlike Bob Warfield at http://www.cnccookbook.com/ (font of wisdom to whom I am massively indebted for his encyclopedic blog), I don't happen to have a second mill handy to modify the first one with. The problem then, is how do you modify the machine that you need to use to modify the machine? Thanks to a little inspiration from this guy http://woodgears.ca/, I decided to make temporary replacements for the saddle and the head-slide out of birch plywood. I do have a small and thoroughly crappy XY table which I bought for a hundred and fifty bucks or so way back before I got the RF so the saddle replacement doesn't have to be functional. A couple of F clamps serve to hold it in place while the second half of the dovetail gets screwed on and then the same clamps act to lock everything in place against the ways. The absolutely fabulous Glacern 6" vice, definitely many cuts above the quality of the rest of my collection of heavy things, is another of Mr Warfield's recommendations. It weighs considerably more than the XY table and altogether this setup, for cross-drilling the saddle for the oil feed, borders on the ridiculous. 

Given the lack of rigidity in the setup I take things gently: it takes three passes at 20 thou per cut with a 1/8" ball nose end mill to make each groove, blowing away the dust with air to keep the cutter free. The recommended feed rate for the cut was something like 2 ipm, very, very slow.... if only I had a cnc machine! Note the ultra-professional tin foil way covers!

Then it is time to take off the head. I'm lucky enough to have a hoisting point for chain blocks in my shop. The rigging is something you want to make sure you get right as the head weighs near 400lbs and is dangerously un-balanced because of the motor. I'm using retired climbing gear. It really would be nice to have some proper eye-bolts in the head.

I needed the temporary head-slide to be functional so I assembled everything to fit closely and then used a couple of long 3/8" machine screws with nuts press-fit into holes drilled into the plywood. These, along with the original jib locks (short lengths of rod cut square on one end and at 60 degrees on the other) tighten down the jib and hold the head in place. 

After a while I got tired of holding the air and rigged up a magnectic base to hold some pneumatic hose with a needle valve to control the flow. That leaves two hands free for the wheels.

Blurry photo, but its all done. In retrospect, I guess it would have been marginally better to cut the long grooves on the diagonal to optimize the oil distribution on the ways.