[widgitmaster]

First I started with a chunk of round cast iron, because it is soft, east to machine and strong!

I faced both sides in my lathe and turned 1/2 the diameter until it was complete.

Then i bored and counterbored a hole in the center to accept a 1/2" diameter shoulder bolt with .75" long shank, making sure the head was slightly below the surface. The bore was a close slip fit for the shoulder bolt.

Then I grabbed another chunk of cast iron, and machined it to 3"x1.25x.750
Then I drilled a shallow hole in the center of the .750 wide side, 3/8 in from the end. Then I bottom tapped the hole for 3/8-16 UNC, to accept the thread on the end of the shoulder screw!

Then I drilled and tapped a 1/4-20 UNC hole in the other end of the cast iron block to be used by the handle.

Next, I took the cast iron disk and machined two flats 1/2" deep on the counterbore side, leaving a 3" wide parallel surface to be used when clamping it in the vise.

Next, I calculated the distance for the stop pins, as .375" + .125" =.500
Thats half the .740 block and half the pin. then I moved X-axis .75 on either side of center, and Y-axis .500 to drill anad ream two slight press fit holes for standard dowel pins.

Once the block was fastened to the disk with the shoulder blot, I dialed the disk in one more time and drilled & reamed a press fit hole in the rotating block for a 1/18" dowel pin. Drilling it after assembly ensures the 1/8 dowel will be exactly in the center of rotation!

Then I grabbed a 1/2 dia x 3" piece of 303-SS and drilled & tapped the ends for 1/4-20 UNC, then I ran a piece of 1/4-20 threaded rod in until it jammed tight in the bottom of the holes, and bandsawed off the excess, leaving a 1/2" of useable thread!

One end screwed into a little 1" dia plastic ball-knob, the other screwed into the rotating cast iron block.

then i made a little block from scrap cast iron, to be a clamp which holds my little parts on the pin in the slot on top of the rotating block!

I put the fixture in my mill vise, dialed in center, and again calculated the offset for the cutter. The cutter is a 5/32 dia 4-flute carbide endmill, so the offset is radius + (1/2 cutter diameter)