I bought a Mastery M1 to replace the stock Fender bridge on my 2017 Jaguar during the week. I asked at a store to double check that it was compatible – I wasn’t sure if I needed the kit, including the thimbles – and was told it was.

I then found that the posts on the Mastery were too wide, by about a millimetre or so.

I searched everywhere online to try to figure out what I needed to do to fit the thing. I was hoping that it would be something that I could do myself, but I really didn’t want to tackle anything that was irreversible.

I couldn’t find anything specific to the American Pro, which is why I’m writing this up, on the off chance that Google lands someone else here who is thinking of doing the same thing.

Long and short of it, it’s a doddle. The plastic mountings [thimbles?] that the stock bridge fits into are less than a centimetre deep. I very carefully levered them out of the metal fittings they are inserted into using one of the Allen keys that came with the Mastery. As I couldn’t tell the dimensions of them before I started, I initially thought I’d have to take them out and replace them with the Mastery thimbles.

You don’t need the Mastery thimbles.The M1 fits perfectly on its own.

Here’s a quick snap showing the little mounting that I removed:

American Pro Jag with Mastery M1 Bridge