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Hi, this Acoustic Parlor Martin Style5 3/4 size almost done, I need your suggestion for the BRIDGE PLACING.
I used floating tailpiece and actually archtop bridge but I made modification on it (cut or removed the bottom).
And my question: Do I have to screw the bridge down to the soundboard to make it unmovable, because everybody tend to move it straight (cause they thought that the straight bridge makes the right sound), however with that certain angle, i found that my tilted bridge sounds just right according to electronic tuner (checking the tone similarity between the open strings and the 12th strings).

and should i screw it or glue it?

* i've set a bridge plate stock under the soundboard in case of screwing is needed

thanks, herry

Hi Herry,
I wouldn't screw it down. One advantage to a "floating" bridge is , if you change string gauges, you can change the angle slightly to adjust the compensation. You could put a couple of decorative fiducial markers next to the ends of the bridge to realign it quickly after someone "fixes it".

If you are relying on an electronic tuner to adjust compensation it's not a bad idea to also check the first fret against the 13th fret.

Thanks, Clay, what someone usually use for marking?

Hi, what someone usually use for marking bridge placing.
thanks

http://en.wikipedia.org/wiki/Fiducial
I think by fiducial he's just meaning a point of reference.
As far as I know, I cant think of anything at all "usually used" as a reference marker for a bridge.
Stick-on abalone/black fret marker dot?
An permanent alternative might be to inlay a small black / abalone or MOP dot each end of the bridge area maybe?
But taking great care not to lift any of the spruce or finish in the area/ finish, and you would have to refinish the top. It's a tricky one.
If I was doing it I might try maybe a 2 or 3 mm diameter, - a downcut router bit may be the best, but don't take my word for it - anyone else got a less dangerous suggestion?

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The name catgut is confusing. There are two explanations for the mix up.

Catgut is an abbreviation of the word cattle gut. Gut strings are made from sheep or goat intestines, in the past even from horse, mule or donkey intestines.

Otherwise it could be from the word kitgut or kitstring. Kit meant fiddle, not kitten.

Colin my friend what's usually been used to mark bridge position for arch top bridges are the sound holes/scrolls. The points have marked the starting point for intonation and placement for far longer that you and I have walked this earth. So there was/is a method to where those holes were indeed located!

Thanks Hesh, I wasn't actually aware of that, good to know.
But I was talking about a flattop guitar with a soundhole in its "normal" position.
Maybe I m barking up the wrong tree here.
But in this particular case I think the guitar has no "F" holes, being a [quote] Acoustic Parlor Martin Style5 3/4 size [/quote) albeit with arch-top style bridge and tailpiece. Something like this? -http://antebelluminstruments.blogspot.co.uk/2012/04/c1890-cincinnatus-parlor-tailpiece.html

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The name catgut is confusing. There are two explanations for the mix up.

Catgut is an abbreviation of the word cattle gut. Gut strings are made from sheep or goat intestines, in the past even from horse, mule or donkey intestines.

Otherwise it could be from the word kitgut or kitstring. Kit meant fiddle, not kitten.

Understand and for a flat top there isn't any permanent reference that I know of either but you can simply measure nut face to the 12th and double it and that will get you close.

For intonation since these bridges are not individually adjustable I simply tune to pitch and set the high e and low e by measuring intonation on a strobe and moving the bridge for each of the e's forward or aft as needed. Easy peezy!

In time the bridge will mark the top like it or not... But you can't trust these markings because the bridge may have never been properly located. But the marks can be a good starting point as well.

Many arch top bridges want to lean too especially if the adjustors, height adjustors are very extended and that needs to be factored into where they are located to account for the lean.

Be sure to fit the base to the top too for maximum contact area - process is the same as fitting a typical acoustic bridge only the arch top bridges are harder to hang onto but with a little creativity you can make a holder for this.

Another option would be to simply glue it to the top as usual. I make ladder braced guitars with tailpieces and glue the bridges in place just as if it was a pinned bridge. A couple of advantages - you can remove all the strings at once if you want to and the bridge doesn't run off and hide under the couch, and of course once you get the intonation spot on it won't change



fwiw - I also build arch top instruments (mando's) and leave bridge floating, but the points on the f-holes are the reference marks for replacing.

You could glue it in place but I wouldn't for the following reasons:

Bridge placement issues during a restring are eliminated if you only remove and replace one string at a time.

The bridge pictured has a VERY small foot print but still some height. I suspect that there may be some risk of the bridge lifting in short order because of the small foot print and torque from the height of the saddle, bridge.

If you did glue it finish would have to be removed under it and this limits your ability to intonate the instrument differently when and if the box geometry changes or you change string gauges.

If you had a conventional sized bridge such as our friend Freeman then I would be more inclined to glue it down.

Also leaving it floating gives you the advantages of a floating bridge. For example, change string gauge and your intonation will be off. With a floating bridge setting the intonation is easy, no tools required, and fast and can be done on the fly at a gig too.

http://www.sinier-de-ridder.com/pdf/sin ... ridges.pdf

On that web page you will see some examples of marquetry that is placed at the ends of the bridge and can mark it's location. The cut work is glued to the top of the soundboard so no inlaying is required. The examples shown are rather elaborate, but a simpler design could be made and would function equally well.

Thanks, Clay S, Colin North, Hesh, Freeman, finally I use transparent cellulose tape and add dot mark under the bridge
Thanks a lot, herry tze