Blank back for a Katsu Tools dial indicator

Bought a "Katsu Tools" Dial Indicator from ebay. It has a large mounting hole on the back face which is not very useful for mounting it to anything; a more secure connection can be made by crimping something onto the device's stem, but in this case the protruding hole gets in he way. Instead of hacksawing off the plastic mounting hole, I designed another, flat, backplate after measuring the existing one.