Mike Hill Plasma Table
I attached three photos of my initial test with .5" plate. The test hole was .75 inches.
[1561] picture from the front side just after cutting
[1565] picture from the backside before dross removal
[1571] picture from the backside after removing the dross with a metal scraper.
The dross was very lightly attached so removal only took a few seconds.
I measured the hole from the front side with calipers and the cut was within 1/64" of an inch. The backside was within 1/32". The plasma arc creates a natural bevel so the backside will always be slightly smaller. If you needed more precision than that we could cut the holes smaller by 1/32" and then chase them through with the correct sized drill bit. With most of the material removed this should be a pretty quick operation.
If you need any parts cut let me know.