Originally Posted by DannoXYZ
I suspect that your frame may be out of spec. Previous headset installations probably expanded the headtube. Multiple uses of the crown-race facing tool may have removed a little too much from the fork as well. Measure the frame, fork and headset parts and compare to the specs given by
Park Tool's Headset Standards Summary. You might find that your frame's dimensions are on the large-clearance end of the tolerance ranges.
It appears in your case that there's a snug fit with no free-play; just not a tight interference fit. So some Loctite should be fine.
The reason that I think this is not the case (my frame being out of spec) is because all of the other JIS headset cups that I have seem to fit properly, there's only one cup out of three JIS headsets (so, one of six cups) that slides right in. Only one crown race slides right on, too - the other two seem as if they fit normally. That said, it certainly seems from a manufacturing standpoint that variability is more likely to come from the head tube and fork crown than from the headset parts. But the headset parts themselves clearly show variability.
Originally Posted by operator
I just took a beer can and shimmed it. I wouldn't do this on a expensive headset though.
Wouldn't work here - that's way more thickness than I'd need to make up in this case.