Mill Knee Hand wheel
© Frank Ford 2004; Photos by FF
When I bought my Bridgeport clone, I had it set up with power feed for the only X-axis, figuring that would do well enough for quick table travel and nice finishes. Later, as I cranked like crazy to raise and lower the knee, I wondered if I should have gotten a power unit for it as well. A friend suggested I make an adapter for a drill motor to use when I had to do a lot of cranking. Later, as I bumped into that long crank handle for the hundredth time, I wondered about whether it needed to stick out so far.
The result of my wondering was to replace the crank with a hand wheel that would still allow room for both Y-axis crank and my knuckles. I got an eight inch diameter chrome plated cast iron hand wheel with a swivel handle from Reid Tool Supply, and fitted it to the shaft:
Now the original long crank hangs on the wall until I need the extra leverage for a heavily loaded table. The hand wheel gives me just the right mechanical advantage and a MUCH shorter cranking stroke, so the knee moves up and down far more easily and quickly. AND, I don't have to remember to take the crank off and turn it around backwards so I don't jam my leg against the handle every time I walk by.
At first blush, the nine tooth fitting seemed a bit daunting, but as I stared at it for a while, I realized how easy it would be to machine. I didn't think to take pictures of the job, so the best I can do is a quick description. The key to the operation became apparent when I noticed that the upper and lower edges of opposing teeth were in a direct line that exactly bisected the diameter of the shaft:
So, all I had to do was center the hand wheel on my rotary table, and cut a straight slot with a 3/16" end mill across both sides of the hub, making sure the edge of my cut was at the center of the hole. Once I'd made nine passes (turning the rotary table 40 degrees for each) I had the job done - and it was a light press fit into the teeth on the knee screw. I haven't even bothered with a set screw, so I can slip the hand wheel off easily and stick on the crank.
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