Double Bass Bridge Specifications

[DAVEinRI]

I just bought a nice adjustable 3/4 bridge from International Violin and have my dremel tool ready to go to fit and install the bridge. I assumed I would be cutting the bridge down, since my existing bridge is only 6" off the top (1929 American Standard plywood.) So I assumed that I would be doing some sanding to bring the tickness down to what it was before I cut it down. However, I was shocked at the amount of meat on this Palatino french bridge! The feet are a full inch, and at the top it is almost 7/16 (compared to 3/16 on my present warped bridge). Even leaving just 1/8 of meat on the foot, when cut down I will have about an inch above the heart. Is this all normal, or should I return this bridge for something else? What is the maximum amount of thickness at the top of the bridge, and the minimum above the heart? And do you agree with the specs described at this site: Link Removed ?

 

[Bob Branstetter]

The bridge blank you bought sounds perfectly normal to me. The thicknesses on the site are reasonable. Using a dremel tool to fit a bass bridge is not. I'm not going to say you can't do it with a dremel, but that would be the equivalent of scrubing your kitchen floor with a toothbrush. I would suggest you look at one of the sites that describes how to fit a bass bridge before you go any further. Here's the URL for one of them.

Fitting The Bridge

 

[DAVEinRI]

Thanks, Bob, for that link. I had been to that site before for serial number research on the instrument, but has missed that page. Very helpful. No, I wasn't going to do the whole thing with the dremel, but I meant that my old girl has some pretty funny dips and curves all around the sound post that will require some interesting fitting, and that seemed the ideal tool (little sanding wheels, etc. - like a dentist!)Can I you or the author for any clarifications? Also, is belt sanding an option vs. planing for thickness, in your mind?

 

[Bob Branstetter]

A 6 inch belt sander works great for thinning a bass bridge. The dremel sander might be ok for some of the rough carving on the feet, but you will probably need a good sharp knife and carbon paper or chalk to get a really good fit. The maple in a brige is relatively hard and my experiece with the Dremel is that unless you go very, very slowly it will either burn or dig into the wood.

 

[Marcus Johnson]

Wow.. great article, Bob, thanks for the link.

 

[DAVEinRI]

Reporting in: The bridge installation went very well, I think, especially for an amateur on the first try. Maybe in a few years I'll try again, but I don't think so. The dremel tool with the 1/2" sanding wheel worked fine on the bridge feet, especially when I got to the carbon paper stage. My old '25 American Standard top looks like the kentucky hills around the sound post, so I have variations of 2 to 7 mm between the thinnest and thickest portion of the two bridge feet. I had to get creative on splaying the feet out before fitting them.(The link article didn't address what to do with an adjustable bridge). I created a tool using a piece of hardwood notched to fit around the adjuster wheels, conforming to the arch above and below the wheels, then cut out 1 1/2 " from the middle of my "tool", drilled holes in the interior ends, and ran a threaded rod with nuts and washers between. This way I could use a wrench on the nuts to slowly expand this piece until the legs were widened precisely 3.5 mm before I began cutting down the feet. My only slip up was an error in marking for cutting down the top of the blank (forgot my Dad's admonition: measure twice, cut once). I ended up having to raise the adjusters quite a bit to get the right string height. The belt sender worked like a charm thinning the blank. WOW, what a brighter, more focused sound now!! Amazing. Thanks for the help and especially for that super article. It covered just about everything.

 

[Paul Warburton]

Kudos to Branstetter! I'm always yelling at people for not taking advantage of the great stuff that TBDB has available for our members through the Newbie Links to the seach/archive function.
One of the biggest things we have available is the ability to ask some fairly big-time players and our fantastic luthiers questions.
Bob always amazes me with his ability to answer luthier type questions really fast, and to post links to books and references to take care of a members question/problem NOW!
You did it again Bob and we thank you!