Unfortunately, the bracket that actually mounts the encoder we burned out on our PlasmaCAM table (yes, it’s true, something from the back of a popular science magazing that works most the time). The bolts, nuts, washers I assume are self explanatory beyond their being #10-32. Honestly I don’t know exactly how long the bolts are, I dug for them in the “Box of No Return” in the shop, same with the nuts and washers.
The encoder carries the same electrical specifications as the one that andy mark put on from the factory, minus being open frame and suceptible to any shocks/misalignments/runouts in the main drive shaft of the transmission.
The part number of this US Digital encoder is S4-250-B. That is, an S4 fully assembled encoder, 250 counts/rev, Ball bearing shaft.
The specific coupler is from McMaster (since we needed it quick) but could be obtained for less money from Helical (about $6 from them, $22 from mcmaster) is a 9861T609 coupling. This is a flexure coupling that goes from a 3/8" to 3/8" bore, 1" in length. If you want even more isolation from vibration/runout/whatever in the transmission, get a larger coupler with the same bores. The longer the coupler, the more isolated, however, the more weight/size.
Let me know (in this thread) if you have any problems or further questions.