Governor for a fireside phonograph does it need two set screws?

[nippers_lounge]

I noticed that the governor on my fireside phonograph has two brass collars . The middle collar has a set screw but the collar on the right does not, however there appears to be a hole for screw? I was told on the Talking Machine Forum that i don’t need a second screw? What doesn’t make sense is why would a second hole be drilled in the collar but not need a screw?

[Henry]

Just a conjecture here, since I'm not familiar with this type of machine, but isn't that collar with the hole supposed to slide up the shaft (i.e, from right to left in the photo) when the governor is spinning? If that's indeed the case, it may be an oiling hole. Also, the hole is not countersunk or threaded, as far as I can tell, so it is doubtless not intended to hold a screw.