Hi Sean
I think the following sketch drawings may suggest an alternative that will give a very rigid result.
Just drill and tap the front plate 4 x M12, Drill the back plate with 4x12mm holes and use M12 rod and lock nuts to carefully set the position of the plates.
Now insert your spindle unit.
Finally clamp two sides and a bottom to the unit to make a mould they can be anything that comes to hand, but before you attach them coat the inside surfaces with wax to stop epoxy sticking to them. OOps I have given the secret away. The unit will be filled with epoxy resin and bone dry sand, about 15% epoxy by volume, not that much really. I used this process to build a small grinder a while back. I use it almost every day to grind my lathe tools.
**LINK**
You will notice in the second see through illustration below I have added 4 long nuts for a possible base mounting point. You can cast attachment points anywhere you choose, just screw them to your mould plates in the correct position when set just remove the screws.
Regards
John
![housing.jpg housing.jpg](data:image/gif;base64,R0lGODlhAQABAAAAACH5BAEKAAEALAAAAAABAAEAAAICTAEAOw==)
![housing2.jpg housing2.jpg](data:image/gif;base64,R0lGODlhAQABAAAAACH5BAEKAAEALAAAAAABAAEAAAICTAEAOw==)
Edited By John McNamara on 12/12/2017 13:19:40