I've just finished my conversion (key conversion anyway). I've a similar round column mill. I milled a 0.75 flat all the way down the column 180 degrees from the rack. Ground a .75x.375 cold rolled steel parallel and then drilled five counter sunk through holes for 1/4-20 socket head cap screws. Align the gound key and transfer the holes. Drill and tap the column for the five 1/4-20 bolts.
Use the flat as a guide to mark the head. Cut the key in the head. There's plenty of room in there for it. I scribed it out, then drill a bunch of holes with a .125 bit. Hack sawed the ends then knocked out the rest with a chisel and hammer. This saves a ton of file work. Do this to both top and bottom. Figure on three hours of filing by hand to get the fit just right.
Mine was belt drive, so I had to also knotch the mid pulley and sheet metal cover. I also added some adjustable "gibs" to the bottom of the head so the play can be taken out. All in all it took me a couple days to complete. I just got my angle plate in, so no chance to see how close it is.
David  |