[R-390] Looking for Knob Clamp Screw

[Barry]

One of the clamp screws for the KC/MC knobs in my R390 is a hex-drive and the other is the standard Bristol spline drive screw.  Anyone know where I might find a Bristol screw (5/8" shaft length)?  I realize this is quite a long shot and this list is one of the very few places that might know where something like this might be had.

Hex drive isn't a killer but would really like for both of the screws to have the original Bristol drive if possible.

Thanks,
Barry - N4BUQ