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View Full Version : Why aren't mando bridges fixed?



Crowder
Jan-26-2004, 9:03pm
Knowing that there is an optimal bridge placement for every mandolin, and knowing that not only the placement but the fit of the bridge are crucial to optimal tone and intonation.....why aren't bridges fixed in place? Or, why is the optimal bridge position not indicated somehow on the face of most mandolins?

I understand that you don't want any sort of interference from glue, etc. between the bridge feet and the mando top. However, once I know my bridge is fit and placed perfectly, I'm really tempted to get a piece of that clear pickguard material and lay a thin strip just behind the bridge's feet so that I can always replace it to the right spot.

Anyone else got any tricks for getting the bridge back to the right spot reliably?

Chris Baird
Jan-26-2004, 9:55pm
It is far better to have a floating bridge. The advantages being easier setup, increased accuracy of intonation, increased versatility for precise intonation over a wide range of heights and string gauges, ease of experimentation with various materials, etc...
Your bridge is in the right spot when the fretted 12th note is exactly 1 octave above the open string. Move forward if flat and move back if sharp.

Joe Mendel
Jan-26-2004, 11:03pm
If you like your action really low, the intonation will be correct with the bridge in one place. If you decide to raise the action, the bridge will have to be moved to another place for the intonation to be right. Also, if you change string gauges/string brands, you'll have to change the bridge position for correct intonation.

ShaneJ
Jan-26-2004, 11:11pm
What if you know how you like the action and know the strings you like best? If you did want to somehow attach the bridge to the top, how would you do it? Would there be "interference" from glue, or would a complete connection between every last fiber of the bridge feet and the top enhance the vibration of the top (and sound)?

I assume a couple staples shot in from underneath would not be the wise choice!

Seriously, though....seems like it might be a good idea. Maybe you could start with a thicker chunk of spruce and carve away everything but the top AND bridge.

sunburst
Jan-26-2004, 11:29pm
SJennings,
I don't think staples would be good. Maybe two drywall screws through the back of the mandolin, through the top, and into the bridge feet. Then you could loosen the screws and move the bridge if you had to. http://www.mandolincafe.net/iB_html/non-cgi/emoticons/biggrin.gif
Oh..........never mind. Must be the cabin fever from the snow #http://www.mandolincafe.net/iB_html/non-cgi/emoticons/biggrin.gif

Fretbear
Jan-27-2004, 12:00am
My flat-top guitar developed a "belly" over the years, and the bridge saddle slot had to be (expensively) filled and re-routed in a new position to correct the intonation. Mandolins rule!

Crowder
Jan-27-2004, 5:29pm
All good points. I think I will proceed with Plan B, which is to have the instrument professionally set up per my specs, then find a near-invisible way to mark where the bridge should sit on the mando top based on this setup. Now, where can I find some very thin, clear pickguard material??

Scotti Adams
Jan-27-2004, 8:59pm
Crowder..do as I do when I find it neccessary to remove my bridge...just take some masking tape....out line the base of the bridge on a couple sides by making sure the edge of the tape is right up against the base. That way you know right where the bridge needs to go when you put it back on...then you can just simply remove the tape when you are done. http://www.mandolincafe.net/iB_html/non-cgi/emoticons/coffee.gif

Bob A
Jan-27-2004, 9:55pm
A friend of mine who deals instruments told me about the guy who bought a uke, had it "tuned by a professional", took it home and applied a drop of epoxy to each tuner gear. "Now I'll never have to tune it again!"

Lee
Jan-27-2004, 9:55pm
Yes, use drafting tape, it's less sticky. Lay down tape to mark the bridge position front-to-back and also side-to-side. I only remove all 8 strings at once if I'm going to put some fresh fretboard oil on. And then I use a cotton cloth to scrub off the greenish brown residue that accumulates on either side of each fret down by the fretboard, using my fingernail inside the cotton cloth, side to side. Anyone else do this?

GTison
Jan-28-2004, 10:53am
When I got my new mando back in July, the gruhns had put blue masking tape on the top to mark the bridge placement. When I pulled it off I noticed I could still see where the tape was. I buffed it a bit but I still know where the corners and straight lines were. I'm not so sure about the use of tape anymore. ( I don't take them all off anymore or take care of my instruments as I used to before I had children.

sunburst
Jan-28-2004, 11:15am
Bowfinger, Masking tapes are not created equal. That blue stuff will damage lacquer. If you go to a paint store, you can find out what the various tapes are meant for.

However! No masking tape should be left on a finish for a long time. The recomended time information is available at the paint store too.

I'd say whoever put that tape on your mando and left it there owes you an apology at the very least.

Scotti Adams
Jan-28-2004, 11:23am
..and if worse comes to worse...you can always see where the bridge has set because there will be a faint outline of the bridge in the finish after a period of time..

Mando Medic
Feb-03-2004, 12:08pm
Scotti, Just because you can see where the bridge was, does not mean that is where it's suppose to go. On well made violins, the inside point of the F hole at the center is suppose to be the makers refrence to where the bridge goes. On "Some" well known mandolin makers, the same thing applies, however, they all need to fine tuned. This, as you know, can be done by playing a note at the 12th fret and then playing it open. If the 12th fret note is higher or sharper than the open note, then the bridge is too close to the fingerboard and must be pulled back towards the tailpiece a little. This is repeated with a retune after each incident until the instrument is in tune.

One of the primary reasons bridges are not glued is, as the instruments dries and shrinks, or expands here in Oregon, the inntonation will change some. If the bridge is glued down, how will that happen? Also the changing of strings in brand and guages will affect the inntonation too. Actually, years ago, I did glue down some bridges and as luck would have it, they reappeared at my shop not too many years ago, and sure enough, the position of the bridge was wrong. Yep, I had to cut off, grind and do finish work on the tops. Sucked!.... Don't glue the bridge.

Scotti Adams
Feb-03-2004, 12:50pm
..your right Ken..but it will give you somewhat of a starting point..