Thurston Moore JM Brass Conversion Thimbles, Mastery Bridge

[Danley]

Hey Danley - appreciate you sharing. Perhaps not as elegant, but definitely a solid solution. Just so I'm understanding correctly - you drilled the existing AOM threaded thimble cavity to open it up to receive the second thimble for the vintage bridge? Just want to make sure I'm interpreting your images correctly. Thanks!

That's correct. Since the Mastery should work with vintage bridge cups this ought to work for you too. I used a few drill bits to enlarge the hole in increments/evenly. I didn't drill it the full 9mm - stopped just short of that, then filed it out for a very tight fit.

FYI - If you use import/MIJ cups, you will need less drilling than AVRI/US cups (as I discovered.) The MIJ/import cups are smaller.

[noctisariel]

This is super helpful Danley, thanks for sharing man! Glad I have a simple solution I can try if I'm not able to get my hands on a set of Johns beautiful brass thimbles. Cheers!

[Danley]

This is super helpful Danley, thanks for sharing man! Glad I have a simple solution I can try if I'm not able to get my hands on a set of Johns beautiful brass thimbles. Cheers!

Staytrem makes conversion bushings FYI, but they're almost impossible to locate nowadays - Have fun!

[noctisariel]

Perhaps someone else can illuminate exactly how John's solution is functioning, because I am confused about one thing...

The Mastery thimbles aren't going inside of these brass spacers that John made - are they? Just want to make sure I'm interpreting the sequence of components correctly...

MASTERY BRIDGE POST ---> BRASS SPACER ---> GUITAR BODY

AND NOT

MASTERY BRIDGE POST ---> MASTERY THIMBLE ---> BRASS SPACER ---> GUITAR BODY

Unless I'm not understanding correctly, wouldn't the bridge posts be bottoming out in the guitar body (as opposed to the bottom of a thimble) when setting the action, and would this not be an issue?

[Danley]

Maybe I didn’t read carefully, but I assumed his brass thimbles weren’t drilled all the way through (so have their own bottom) - that’s the only way I assume it could work properly, and how I would do it if I was taking the effort.

[timtam]

MASTERY BRIDGE POST ---> BRASS SPACER ---> GUITAR BODY
...
Unless I'm not understanding correctly, wouldn't the bridge posts be bottoming out in the guitar body (as opposed to the bottom of a thimble) when setting the action, and would this not be an issue?

This ^^. The OD of the brass spacer is specific to the Moore JM's Gotoh TOM (Fender #0077022000) bushing's OD (different TOMs have different bushing ODs). The spacer's ID is that of the Mastery post's OD. The spacer is indeed drilled to the same depth as the Mastery thimbles (ie it is closed at the bottom).

[noctisariel]

Thanks Danley and Timtam for chiming in - makes a lot more sense now. Was tough to tell from the photos, looked like it might have been drilled all the way through in one of the shots, but re-reading the part where he set the drill depth basically confirms it wasn't drilled all the way through in order to leave a bottom.