Double Bass What a difference 1/4 inch (or 6.35mm) makes...

[Don Hergert]

While I'm extremely happy with my bass, one disadvantage of having a powder-coat finish on an aluminum bass is that it's very slippery.

While practicing today I noticed that my bridge (Deuce D1) had worked it's way up the bass's table about 1/4" (6.35mm). I hadn't been keeping track of it so it was sort of a surprise. While the Deuce bridges won't easily flop over, they do slip on a slippery surface.

Soooo, that discovery brought out a number of measuring tools and I got the bridge back in place... And then I noticed the action was a little lower than I prefer, so I also adjusted that to my preference of 3/16" (4.76mm) at the G to 1/4" (6.35mm) at the E. And when that was adjusted I double-checked my sound post, happily it had not moved.

Once done, I got back into a practice mode. And wow, the volume was up noticeably! Maybe 15% to 20% by my perception...

Now from other instruments I'm aware that often if you change even the most subtle thing in the way of bridge setup, you get different sound results, but I hadn't seen this on my bass before. I'm very glad I stumbled into this. I'll be watching the bridge more carefully from here on!

 

[turf3]

Run a pencil around the feet of the bridge so the correct position can always be restored quickly.

 

[Don Hergert]

Run a pencil around the feet of the bridge so the correct position can always be restored quickly.

Done, sort of... I put some discrete marks there that will stay somewhat longer on powder-coat.

 

[Ortsom2]

If the top is so slippery, maybe try balancing the setup, with the bridge perpendicular to the top.

With that I mean: not the back of the bridge perpendicular to the top, as is common, but instead the centre line of the bridge (as seen from the side) perpendicular to the top. And the balancing means that the force line of the strings ends up in the middle of the bridge's feet, hence is perpendicular to the top. That should keep those feet from walking.

If you keep the feet at the same location then you'll get a slightly shorter scale, compared to a common setup. The balancing you do with the saddle height.

 

[DoubleMIDI]

But changing saddle height changes the amount of pressure to the top which can be good or bad to the tone/volume.

Why not putting some rosin dust to the top if it is slippery? That should keep the bridge in place and keeps the sound as it is.

 

[RSBBass]

Double Midi beat me to it so I will second the suggestion of rosin dust. I had the same problem on my Shen SB80 which has a slippery poly finish. A bit of rosin dust and it hasn't moved since.

 

[Don Hergert]

Thank y'all!

All of these tried... Balance, rosin and roughing up the feet helps. But, one way or the other the bridge is going to move again sometime. The marks I made won't move until I remove them.

 

[Mike Marshall]

Thank y'all!

All of these tried... Balance, rosin and roughing up the feet helps. But, one way or the other the bridge is going to move again sometime. The marks I made won't move until I remove them.

I have been a machinist since the early 70's one old trick we used when clamping a vise on a machine table was to put a piece of paper under the vise. The paper is just abrasive enough to stop the vise from moving while cutting metal. It may seem hard to believe that even though the vise was bolted with 5/8 screws that it would slide but when two surfaces are very smooth move it did. I think the aluminum on your bass being polished is quite slick and the paper is only .004 thick and you can trim any excess with an exacto knife once you have tuned up.

 

[srbbass]

Double Midi beat me to it so I will second the suggestion of rosin dust. I had the same problem on my Shen SB80 which has a slippery poly finish. A bit of rosin dust and it hasn't moved since.

I love TB! My university has a Shen SB80 with the same slippery finish and the bridge moves in the gentlest breeze. I was searching TB for ideas and stumbled across your response. Gonna give rosin dust a try!