I don't know the Osborne, but these bars have a similar point of "grabby" as all bars i've seen. It has to do with the slot in the saw - some are milled smoother than others. At the very least, I think you'd have to drill and tap some holes to fit this bar to your osborne.
The delrin discs are very nice at allowing you to adjust things tighter than any other bars i've seen. The ones that just expand the bar itself means you have metal-to-metal contact. That's higher friction than these little discs and i've been able to get almost all the wiggle out of my miter guages because of it.
There's still SOME play because one of my slots has a high spot that I one day intend to adjust with some 220 wet/dry sandpaper on a block of wood ... that day just hasn't come, yet