Sunday, April 6, 2008

Radiusing Without A Rotary Table

I have one significant, challenging, educational opportunity left on this replacement latitude adjuster block. There is a rectangular extension, .625" deep, 1.75" long, .75" wide, but the four corners are radiused (.375" radius).

The normal way that you would use a mill to radius the four corners is to put the workpiece in a mill vise mounted to a rotary table which is vertical. You would then position the workpiece such that the center of the rotary table would be aligned with the center of the radius that you need to turn at the end of the rectangle.

Then you position the end mill some distance above the top of the rectangle, start the mill running, and turn the rotary table 90 degrees forward to round off the corner, turn it back 90 degrees to top, and then 90 degrees backward to round off the other corner.

Lower the cutting tool .010", and repeat, until you have the reached the top of the rectangle.

Then do the other end of the rectangle by switching it around.

I don't have a rotary table. Sherline sells one for $270--which perhaps I should buy, since I am sure that I will have other uses for it. The holddown kit I bought last year--I just found a use for it.

It sure would be nice if there was some other way to radius this rectangle without having to spend the money and wait for it to arrive--especially since I am about to write some disturbingly large checks to IRS and the Idaho Tax Commission. I have a feeling that there's probably some way to accomplish this with a lathe, or perhaps with a drill press, since the drill press has a table that rotates.

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