(ignoring fits and tolerances)
Can't see the Ultimarc knobs being a press fit to the SpinTrak shafts, even if accurately machined to 6mm from the factory (where ever GGG gets them machined) and considering from the photo the knob is supplied with a set screw, I was thinking there might be some "play".
The aluminium will melt long before you can expand the hole 0.35mm
You need heat in excess of 1200 degrees farenheight to melt aluminum and it ain't gonna happen in your home oven.
Not interested in a metallurgical discussion, it was a simple "possible" fix depending on tolerance. Certainly something I would try if both pcs were in my hand...it's free and couldn't hurt, no matter, RandyT to the rescue
