Summary

update: ten minutes later. The proper big arms are now included.
Here it is My new and improved spool holders uses a 5/16 or 8mm bolt or all thread as an Axle you can see i have used one of the washers, a spring and a extra hub nut as a tentioner so the spool does not unroll.

Instructions

use a short 5/16 or 8 mm bolt to insert a nut in the hub, the hub spanner wrench is handy. the small part of the hub acts as a bearing surface.
install a hub nut on one end of the bolt or if its all tread use use a hub nut that already has a washer in it. attach the proper hubs to the spool using the bolt. you can use the wrench to tighten if you wish. install the arms on your top rail using a extrusion nut and 5mm cap screw the spool must be inserted while the screws are still loose. capture the spool if desired with to nuts on the out side. be careful one of them will tend to tighten if you dont use a washer and spring. it works just fine with out being captured but my filament had a habit of unrolling.
the only difference between the repraper arms and the regular arms is length. as you can see that is a repraper spool on the long arms in the pictures. I have sucessfully printed in ABS and PLA

Imporved high clearance MendelMax Spool holder for Trinity/Proto/Reprap spools (and many others)