Mandolin Bridge Replacement Question

[Greg Connor]

I want to replace the one piece bridge on my mandolin with an adjustable version. I have a few questions:

1. Ebony or Rosewood?

2. Cheap or expensive?

3. Any special brand?

Any advice is appreciated. The mandolin is a hand made 2 point made by Bruce Brockman in Arizona. It has a wider than normal fret board, affecting string spacing.

This is a great sounding instrument. I want to make it a great playing instrument too.

[pops1]

What wood is the bridge made of now? I would stay with the same wood. You may also consider during the most humid part of the year taking wood off the bridge you have now and setting it up to play well. Then in the driest part of the year making a new one piece bridge that will be a little taller and change them out, it would keep the sound more similar to what you have. If you want an adjustable bridge I would get the same wood, but remember it will have to be fit to the top. I would get good quality, you will hear the difference. You should be able to get a bridge unslotted so you can space the strings the same as your present bridge.

[Greg Connor]

What wood is the bridge made of now?

Thank you for the reply. The bridge is rosewood.

[keith.rogers]

Without seeing/measuring, there may be a reason there's a fixed bridge on that instrument - i.e., you may have some limitations (on adjustable bridge options) due to the height of the one-piece bridge that's there now. Many (most?) adjustable bridges are made for arched top instruments with a neck angle that allows for more [total] height. So, the minimum adjustable height should be something you're looking at. Removing material from the bottom, subject to the threaded screw depth, may give you some lowering, but reducing the height of the upper piece can cause the bridge to sag in the middle.

[Berto Boy]

That's a beautiful instrument!

I would definitely avoid a cheap adjustable bridge as the tone would definitely be step down from your current solid bridge.

Among quality adjustable bridges, you'll find a lot of love for Cumberland Acoustics here. They are made for archtop instruments though and are ~ 3/4" tall. I was able to carve one down to about 5/8" for a mando who's neck was set wrong, that's really pushing the limits though.

I would first contact the builder and have him evaluate the instrument, it may be due for a tune up and perhaps some fretwork. If the action is going up and down with seasonal humidity changes, you may wish to resort to having a second shorter bridge so you can swap them out as the season dictates. If the action is high year round without fluctuation, then the current bridge can be shortened.

There may be quality adjustable bridges out there for flat top mandolins, but I haven't encountered them.

edit: I just watched your other video of when you originally got the instrument and it looks to have a different (ebony) bridge on it. If you have two bridges, have one cut down to give you better playability. Be prepared to have some fret touchup work for low action and good tone.

[Greg Connor]

That's a beautiful instrument!

Among quality adjustable bridges, you'll find a lot of love for Cumberland Acoustics here. They are made for archtop instruments though and are ~ 3/4" tall. I was able to carve one down to about 5/8" for a mando who's neck was set wrong, that's really pushing the limits though.

I would first contact the builder and have him evaluate the instrument, it may be due for a tune up and perhaps some fretwork. If the action is going up and down with seasonal humidity changes, you may wish to resort to having a second shorter bridge so you can swap them out as the season dictates. If the action is high year round without fluctuation, then the current bridge can be shortened.

There may be quality adjustable bridges out there for flat top mandolins, but I haven't encountered them.

edit: I just watched your other video of when you originally got the instrument and it looks to have a different (ebony) bridge on it. If you have two bridges, have one cut down to give you better playability. Be prepared to have some fret touchup work for low action and good tone.

Thanks for the comments. For clarification, this is an arch top and it’s only a year old. The builder sent it with high action and recommended I let it settle in before adjusting. I’m slowly tweaking here and there. My other mandolins are experiencing the usual winter need for adjusting. I thought it might be a good idea to research the idea of an adjustable bridge for this one too.

[mandrian]

Greg,

In Scotland we are blessed with weather (never thought I would ever say that) such that our instruments very seldom need to be adjusted seasonally or otherwise at least in my experience.

However, I was wondering if the type of bridge favoured by Sobell, etc might work for you. It’s easy to adjust down by sanding the bottom of the insert, but if you wanted to raise it later it might be more problematic. But I think it would better suit the aesthetic of your instrument. Maybe one to discuss with the maker.



Regards,

[Tom Haywood]

Sounds like you are planning to lower the action by adding a two piece adjustable bridge. Measure right in front of the current bridge from the mandolin top to the middle strings at the bridge. If it is less than about 3/4", you may have some difficulties finding and fitting a standard two piece adjustable bridge. I would also see how the top braces fit under the bridge to see if you need a full contact bridge or not.

It looks good if you match the fret board wood and the bridge wood. The sound of ebony vs. rosewood is different, but which sounds better for the bridge really depends on the mandolin.

I expect it would be a lot less work to lower the top of the bridge that's on it than to do a full fit of a new bridge. That works with the mandolin's design. It may be that you'll find an action height that works year round.

[Greg Connor]

All great comments guys. Thank You. It’s nice to be able to tap this wealth of knowledge.

[Schneidly]

Vern Brekke makes an adjustable bridge that might be a decent match for your instrument's aesthetic:

http://www.bridgerproducts.com/brekke_bridges

[Jim Garber]

As pops1 said maybe the dry times in Minnesota require a different height bridge. Here are a couple of possibilities:

Have Bruce make you a duplicate bridge that is higher or lower. Maybe you can figure out what the measurement should. Of course, this would also depend on wheter the current bridge works well some of the time. It also might make more sense for a local luthier to copy that bridge and fit it. Unless you are handy in which case you could do all this yourself.

The above is if you are generally happy with the tone. It does sound like you like the tone but not the playability. BTW how wide is your fretboard at the nut?

[mr ken]

The redline mandolin that Steve Smith makes he puts them on is a Cumberland. they fit very well I have #119 . these are as flat as you can get.

[Mandobart]

Based on the hand-built instruments I have, this is my advice:

1. Ebony or Rosewood? - ebony

2. Cheap or expensive? - the best you can afford.

3. Any special brand? - Tom TJ Jessen and Sonny Morris built the bridges they put on the instruments they built for me. I don't think they just build and sell bridges though.

The most important thing IMO is to fit whatever bridge you get to the top of your mandolin. I bought the Stew-Mac jigs for both mandolin/arch top and fiddle.

[peter.coombe]

I second Ebony, and also second the suggestion of a Brekke bridge.

[Greg Connor]

Thanks for all the great comments guys! I appreciate the help.

I have never replaced a bridge on a mandolin before but I’ve been tearing guitars apart for years. My wife sometimes shutters when she sees something I just bought in pieces on the bench.

As for my Brockman Mandolin, I loosened the strings last night, readjusted and attenuated the bridge, and took a good close look at it. Right now the bridge is high, so I’m going to take it down a bit. I think I’ll hold off replacing it for now.

Brekke bridges were mention above. I have one on my Morris Mandolin.

This thread has given me pause, at least for now, as far as replacing my fixed bridge. I’ll take a closer look at both Brekke and Cumberland bridges if I decide to pursue an adjustable alternative.

Thanks again for all the help.

Greg

[rcc56]

Well, if you work on instruments, you could get a piece of ebony and a piece of rosewood, carve away everything that doesn't look like a mandolin bridge, and try both of them on your instrument and see which of them suits you better.

Hint: the so-called one-piece mid 1910's Gibson bridges were actually made in two pieces and glued together-- a base section, and a compensated upper section. You can make one from scratch in an hour or two with a coping saw, a couple of files, a small flat sanding block, and a dowel with some sandpaper wrapped around it.

If you want to make an adjustable bridge, thumbwheels and shafts are available from Axiom Inc www.axinc.net. I believe a 5-40 tap is required to thread the base for the screws. Hint: make the base and install the shafts before you make the saddle. When you make the saddles, drill the holes for the shafts before you work the saddle blank down to final thickness. This minimizes an annoying tendency for the drill bit to split a thinned saddle blank.

[Greg Connor]

Well, if you work on instruments, you could get a piece of ebony and a piece of rosewood, carve away everything that doesn't look like a mandolin bridge, and try both of them on your instrument and see which of them suits you better.

Hint: the so-called one-piece mid 1910's Gibson bridges were actually made in two pieces and glued together-- a base section, and a compensated upper section. You can make one from scratch in an hour or two with a coping saw, a couple of files, a small flat sanding block, and a dowel with some sandpaper wrapped around it.

If you want to make an adjustable bridge, thumbwheels and shafts are available from Axiom Inc www.axinc.net. I believe a 5-40 tap is required to thread the base for the screws. Hint: make the base and install the shafts before you make the saddle. When you make the saddles, drill the holes for the shafts before you work the saddle blank down to final thickness. This minimizes an annoying tendency for the drill bit to split a thinned saddle blank.

All good advice. I could trace the existing bridge on to a new piece of ebony or rosewood and have at it. I even have wood working tools, band saw etc. In the meantime, I just finished doing a little tweaking. I’m getting closer and closer to nirvana.

[Tom Haywood]

Apologies if I'm saying things you already know.

Geometry is on your side. Measure the current string height of the outer G and E strings above the 12th fret. I suggest you post those measurements here for review. Decide on the number you want for those heights to be. Again, post those numbers for review. There are "standard" heights to aim for. The difference in the measurements is the amount you want to lower, and you will lower the saddle by twice that amount. Keep in mind that you will lower the strings some at the saddle below it's top height when you add small grooves for the strings.

IMO, the best approach is to sneak up on the final heights by sanding off some of the saddle top, placing small groves in it just deep enough to keep the string in place, then string it up, check your measurements, and see how it feels. Then repeat. Have spare E and A strings on hand. The saddle top shape needs to match any radius in your fret board. If you are lowering the strings a VERY small amount, one option is to lower the saddle grooves and then sand the wood off the top to make the grooves shallow. Observe the current grooves, because something different could make it buzzy or tinny.

Geometry is very useful to help you sneak up on what you want, but in the end what it feels like and how it plays is what counts. I rarely do a setup without first having the owner play the instrument so I can see how hard or soft they strum and fret, whether they play up the neck, the style of music they play, etc.

Pausing is a good idea. You can see from all the discussion that setups and bridge replacements are both a skill and an art.