I've been looking for a 70mm loader on eBay for a while and I refuse to pay the $250 that these things seem to sell for so I hacked one up out of a couple bits of wood and M6 bolts this evening. The bolts screw in/out to support the two spools and the big screwdriver is how you turn the takeup spool. Obviously this is not a daylight loader

One puzzle I did have is that once the spool was loaded (I went to about 0.5mm smaller than the spool flanges) and installed in the cassette, it did a big unwinding inside the cassette after about a minute. I suspect that means the back of the film will be dragging on the inside of the cassette, so I hope I don't get any problems with scratches.