I decided to replace my waste board. The old one had seen better days and when I flattened it I had quite a step on one side.
First thing I cut a 22.5 X 19 - 1/2" baltic birch plywood. - Lesson #1 - it doesn’t have to be 19" deep as the router can’t go back all that far.
I laid out a 2" grid. -Again the back rows could have been left out. I decided to not have the Shapeoko do the work as it would limit the max size I could clamp down. If all the holes are cut in a 16 X 16 square then you can’t clamp down a 16 X 16 board.
I drilled 1/8" holes on all locations of the grid thinking it would be easier see where to center the forstner bit.
I used a forstner bit in the drill press to cut the hole for the plate of the t-nut. I set a depth stop so it would be just below being flush. Lesson #2 - it should be drilled deeper so the t-nut position isn’t as critical. Didn’t want any being proud of the bottom as I felt that would make the waste board uneven.
Drilled clearance holes for the t-nuts and started to put them in. Had trouble getting them all the way in due to not enough hole depth. Had a bright idea, use a 1’4-20 bolt, washers, and an impact driver to pull them into the board. Lesson #3 - the driver is so powerful that it would muck up the threads in the t-nuts and or just pull them apart.
So I would up drilling the bore a little deeper and then between a hammer and a punch got all 110 t-nuts inset into the waste board. Lesson #4 - next time use screw in threaded inserts.
Got this all done and put a dial indicator in the collet and found the new waste board to be about 0.040 difference from the lowest to the highest point. Guess I’ll flatten it next. I was hoping to get it closer than that, but…
BTW - while checking the offset all of a sudden it started acting really weird. When I would initialize, it would go home and then the right hand X steeper would keep trying to step. The final solution was to resend the default to the controller and then all worked as expected.