I purchased a Gator 5" diameter D1-4 back plate adapter, what they call semi-finished state. I now need to turn down the front face boss profile that engages the matching recess in rear of plain back 5" chuck. And then I need to drill/tap the 3 holes to receive the chuck's bolts. Any words of wisdom prior to embarking on this mission? I thought about ID referencing the pin to a specific hole in the lathe nose to replicate the setup with the chuck mounted. I know my collet chuck & 3-jaw have an orientation that is about 1-thou closer to concentric. In this case its for a 4-jaw chuck so no real concern that way. But apparently the 3-jaw has same recess dimensions if I decide to get it one day. For reference the back plate recess is 95mm (3.740") diameter & 4mm (0.158") depth from catalog specs, although I measured ~0.200" actual depth on the chuck.