Mastery bridge thimble adjustment


I know (now) that you need to widen the holes slightly to fit the thimbles for a Mastery bridge into a Warmoth JM body, but how tight should the fit be for them? I would assume VERY, but a post on the Offset Guitars forum says that Warmoth had suggested that they be a loose fit, loose enough to fall out if the guitar was turned over. A vast majority of the other advice I've seen with this combo of parts seems to indicate a snug fit, but was curious if anyone here had more insight.
All jazzmaster style bridge thimbles should have a tight fit. I don't have any first hand experience with the Warmoth holes/Mastery thimbles, but I don't see any reason why they shouldn't work.

I've read that the Mastery bridge thimbles have a 9.5mm diameter, which is slightly larger than a "standard" JM bridge thimble.

I can't seem to find the width for Warmoth's JM bridge holes anywhere though.
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I can't seem to find the width for Warmoth's JM bridge holes anywhere though.

If it helps, the mounting cups / "thimbles" diameter for the JM bridge Warmoth sells are 9 mm. Which one could extrapolate, the body holes are probably also 9 mm or possibly 3/8".

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I put a Mastery on my Warmoth JM and, yeah, it was a bit of a tight squeeze (especially since my body had been finished from the factory). That being said, the Mastery isn't supposed to rock like the original, so a tight fit on the thimbles is somewhat desirable. I can see how people would say the fit should be kinda loose so that you could swap back to the original, though.

As for me, I never had any intentions of having the rocking bridge to begin with and I've been happy with the Mastery, so it's moot for me to be able to remove the thimbles. Only advice I have is make sure it's paired with the Mastery trem. I find the tuning is a bit more stable and it helps reduce bridge buzz, but that's just my experience..