Locking bridge conversion

I was recently torn between buying a Callaham steel abr1 bridge or an ABM steel bridge for half the price. For me the only advantage to the Callaham was the locking screws so I got the ABM (if anyone is interested I could review it, there's not much talk about this company even though they are at the upper end of the market). I knew I would miss the locking feature so I added it myself.

I was surprised to find that this is not something discussed very much online even though it was a pretty simple procedure and adds a feature that a lot of people would consider desirable. Maybe it's just that there are lots of good youtube metalworking videos for each of the steps and anyone who has the confidence to do it wouldn't need a guitar-specific step-by-step. Well, I'm feeling pretty happy that even with my modest DIY skills I managed to make it work so I'm showing it off!



First I jigged up on a borrowed drill press. I used a slow speed, plenty of 3-in-1 oil and lots of downward pressure to get through the steel. In hindsight I would probably also cover the area in masking tape for a bit of extra protection for the plating. I used a 2.5mm drill bit.

I tapped the thread with an M3 tap and a cheap T-bar tapping tool I picked up on ebay, plus lots of oil.

With the holes prepped I screwed in the grub screws. M3, 4mm length, flat bottom. The same spec as used in a Tone Pros bridge.

Et voila!

Neat work but I don't understand the purpose of locking screws. The string tension on a bridge is not going to let it move anywhere so it doesn't require locking. On combo tailpiece bridges, small screws in exactly the same location are used as a coarse adjustment to set the scale of the saddles for intonation. I have three, old, Gibsons with Tunomatic bridges and none of them have ever shifted up or down without me making them do so.

rick c said:

Neat work but I don't understand the purpose of locking screws. The string tension on a bridge is not going to let it move anywhere so it doesn't require locking. On combo tailpiece bridges, small screws in exactly the same location are used as a coarse adjustment to set the scale of the saddles for intonation. I have three, old, Gibsons with Tunomatic bridges and none of them have ever shifted up or down without me making them do so.

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The theory is that by creating a solid coupling to the bridge post (especially on models whose posts are screwed directly into the body) you get better vibration transfer. The audible benefit from this is of course heavily promoted by hardware makers like Tone Pros, and much debated by internet guitarists.

Personally I'm a fan of the more practical aspect, which is that your bridge assembly doesn't move/fall apart when you take the strings off for cleaning, maintenance etc, and this is the same reason I also do the double thumbwheel trick. When I pay a pro to do a setup for me I don't want that thrown off by a gentle bump next time I oil my fretboard. (I don't have a second set of metric thumbwheels for the guitar above, so I used a plain old hex nut under the wheel).

I have locking bridges on all my Les Pauls, my 2004 Classic has a Gotoh/Tone Pros bridge whilst my 2016 has a Tone Pros, plus I put them on my other Les Pauls that have since been moved on. Can’t say I’ve ever notice any difference tone wise, I just prefer the practical side of it.
:salude