Start off with a pair of these, they are perfect size for powermax 45, not sure what size others use, they are 35mm dia.
I cut one down to 60mm long and the other a metal thickness more at 65mm as I used 5mm for the brackets.
I haven't included a dxf for the magnet mount as it's only a bit of 3mm welded on to suit the magnet/s, I used a old hard drive magnet, which I reckon is a perfect size, if you can't find one of those, there are plenty on ebay of various sizes, I would say 2 x 3/4'' dia should be about right, just bond them on with stixall or tiger seal. I have allowed for the holes to be drilled on the dxf, I used 8mm bearings, Just slice open a old bearing, see knew they would come in
Where the bearing is bonded in I just countersunk until the bearing was half way in, then super glued. The holes in the back plate where the ball bearings locate into I drilled 7.5mm, which gave about a mm gap when located, same with the magnet don't have it touching the back plate aim for a 1mm gap, in case any junk gathers on the magnet. That's about it really, having the lower mount separate really helps keeping the three points perfectly aligned.
You can get sideways adjustment on the mounting screws, but the other way depends on accurate cutting of the ally mounts, it's not that hard and could be tweaked with a shim if it's a bit out.
The dxf includes a plate with 2 holes I used as a drilling template for the upper mount.
