I have had a JTech 4.2W laser for about 3 years. It was useful to be able to swap quickly between carving and laser. Since I have changed to an 80mm spindle, I had no bracket that could be used so I made one from 10 x 50mm aluminium bar. This bracket fits directly to the carbide 3D 80mm HD spindle mount.
I drilled 2 holes for the 5mm cap head bolts that fix the bracket to the 80mm HD spindle mount. I drilled two 3mm holes for the locating pins on the back of the JTech shroud. I used a 3.175mm (1/8") 2 flute carbide cutter (DLC coated) to bore 4 holes 10.2mm in diameter using a helical toolpath. This was to allow easy insertion of 10mm neodymium magnets.
The holes were bored to a depth of 9mm so that the magnets would be as close as reasonable to the magnets in the plate attched to the JTech laser shroud. I used 3 x 10 x 2 magnets in each hole and glued them in place using CA glue. Only the first magnet was glued into each hole. The magnetism held the remaining two magnets in place and increased the magnetic pull so that the shroud attached very securely. The shroud was positioned so that it protrudes 10mm below the end of the collet clamping nut.