Machining the frame end plates and bearing bores .........
End plates for the engine frame are made from .375" thick plate and finished to overall size of 6.000" wide x 5.250" high. Overall size will be machined with the plates clamped in pairs.
I put a center mark on each side of the plates to scribe a layout circle for the bearing bores as a roughing guide.
Bored thru 13/16" clearance for the crank shaft and as a reference bore to locate when doing the opposite side.
Finish boring for slip fit to the ball bearing using a flat bottom ground boring bar. ( layout line visible ) The bore is half the thickness of the bearing in depth. Added a counter bore .010" deep to clear the inner race of the bearing.
Used a 45 degree chamfer bar to to break the bores edges. Flip to the opposite side and pick up bore and repeat the operations.
Next operation will be to cut the angled features on the plates to a 4.000 width at the top to match the bottom plate width. Used a height gage to scribe accurate layout lines where the cut runs out.
Set up with sine bar for the correct angle and used mill stop to locate the position of the sine bar so opposite side cut would be the same.
This finishes the plates for now.
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