Bottom plate in the lathe

After squaring up the bottom plate at the mill, I put a rough layout on the top surface to act as a rough guide at the lathe. I made an “X” across the piece with layout fluid and scribed a line from the corners to find the center. I punched the center and then scribed the ID and OD for the grove and the corner radiuses.



I placed it in a 4 jaw chuck using ¼ inch dowels to bank off of. After squaring it in the chuck I center drilled, drilled and bored the center hole. I did not tap the hole because I need a smooth surface to indicate when I take it back to the mill.



Here at my school, we have boxes of old high speed steel tools from students past. I didn’t want to have to grind my own tool so I dug until I found one that would make a good trepan. It took a little fussing to get the speed and rake right because it kept wanting to chatter but once we got it straight, it was a quick and simple job to cut the groove.



The finished groove:



Finally I cut half of the corner radius, flipped and squared the piece and cut the remaining radius.



I'm a little behind schedule as I get into the swing of things. I've ordered more stock so will be picking up the pace in the next couple of weeks. Next I will move back to the mill where I will drill and tap the remaining holes.