And as promised:
First mount a fixture plate to the mill table, a piece of MDF that I had used as a spoil board for some other parts.
Then set the ''0'' on the fixture plate. This is 1'' off the the part in the X and Y axis, per the CAM setup
Then move the table so the endmill is roughly centered on the spot, anywhere +/- 1/2'' or so would be fine. This is just to generally locate the work to the spindle and have the work more or less centered on the fixture plate. Zero the X and Y axis at this point. This becomes the 0,0 for the rest of the work.
Then pocket out a 0.300 deep pocket for the workpiece to set in. This is a press fit for the finished side. Holds the part at an exact known location because this was done from the part drawing with the same CAM setup.
This is where the part was left yesterday. Excess material that needs to be removed for the part to fit in the fixture plate. this was part of the plan for machining this part. This allowed me to have a 1/4'' flange all around the part for clamping.
Over to the band saw and cut off the excess material off of the work piece.
Press the part into the fixture plate and hold down with a couple deck screws and washers. You can't really see it in this picture, but the flange sits about 1/8'' above the fixture plate surface. The order of operation and holding methods for this entire part was planned while I was designing it. This is really kind of a difficult part to machine.
Then chew out the center
And the center is done, about 84 minutes. Probably don't even need the hold downs, but I'm a belt & suspenders kind of guy
Then reset the clamps, and prepare to finish the outside profile. The question is; will surfaces line up with the previously machined surfaces when it's done?
We'll see how repeatable my machine really is.
And finished. The surfaces lined up with less than 0.001'' error. You almost can't even see a line where the two sides meet.
Next is the scale box..... Stay tuned.