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Locating, aligning, and gluing bridges
http://www.luthiersforum.com/forum/viewtopic.php?f=10101&t=30332		 Page 1 of 2
Author:  James Orr [ Wed Dec 15, 2010 12:29 pm ]
Post subject:  Locating, aligning, and gluing bridges
Needing only to make a nut and saddle before stringing up acoustic #2, I've been reflecting on the progress I've seen in this one and analyzing the processes I still struggle with.

Locating, aligning, and gluing the bridge still gives me trouble. I've been using Stew Mac's saddlematic to find the saddle position, and because my bridges at this point are pre-made, the bridge position as well. There tends to be play in the saddlematic, and then movement under clamping pressure using the Stew Mac bridge clamping caul and Ibex bridge clamp with HHG.

I saw a picture on Hesh's site last night (http://www.lenaweelutherie.info/page6/p ... age21.html) that gave me a bit of an Ah Ha! moment. He used pins in the picture in the saddle slot, which would be a great way to quickly get the bridge positioned once glue's applied, and also to keep it from moving on clamping pressure. Similar to using pins in fret slots when gluing fingerboards.

What are your procedures for locating, aligning, and gluing your bridges?
Author:  Rod True [ Wed Dec 15, 2010 12:41 pm ]
Post subject:  Re: Locating, aligning, and gluing bridges
I've set up my centerline finder from Luthier Supplies for locating my bridge, based on the scale I've chosen.

I scribed a ling at the 14th fret for the scale I use, then I figured out where the front of my bridge needs to be based off my saddle slotting jig (this is where consistency comes into play). This of course all took time and a bit of simple math, but now that I have it done, it's very quick to locate the bridge. When I locate the bridge, I tape it to the top over the wings, then clamp it in place. I then drill through the two E string bridge pin holes through the top and bridge plate. When I glue the bridge on, I use 2 3/16" dia pins to locate the bridge.

Sorry, I don't have any pictures to help with the description.
Author:  JJ Donohue [ Wed Dec 15, 2010 12:45 pm ]
Post subject:  Re: Locating, aligning, and gluing bridges
1) Position bridge precisely using the saddlematic and tape in place.
2) Drill 1/16" holes through E and e. Fit holes with 1/16" pins or drill bit.
3) I use the SM bridge clamp. I drill holes in the clamp that allow the pins to pass through.
4) Warm up the bridge and spruce
5) Apply HHG, align with pins and clamp within 45 seconds
6) Clamp for 12 hours.
Author:  Tom West [ Wed Dec 15, 2010 1:02 pm ]
Post subject:  Re: Locating, aligning, and gluing bridges
James : I have what is called a story stick. It is just a piece of wood stock about 5/8" by 1/4" by about 30" in lenght. This has a stop on one end of the same size stock about 1" long.This hooks on the headstock end of the fingerboard and there are marks for the forward edge of the saddle on the side of the stick for the high E and low E strings.These marks are made by a sharp utility knife.The marks are set at the scale lenght plus the set back for intonation.Using this and a straight edge on the edge of the fingerboard for lateral placement of the bridge I clamp the bridge in place.Then I clip the heads off a couple of small finish nails and use these to drill holes through the saddle slot into the top and bridgeplate. These homemade drills then become the locating pins when you glue. Recheck your positioning after setting pins.
Tom
Author:  woody b [ Wed Dec 15, 2010 1:03 pm ]
Post subject:  Re: Locating, aligning, and gluing bridges
I locate and center mine with Tracy's centerline finder. Then hold it in place with 2 drill bits through the outer bridge pin holes.
Author:  Pat Foster [ Wed Dec 15, 2010 1:22 pm ]
Post subject:  Re: Locating, aligning, and gluing bridges
James,

I'm still in the dark ages as far as figuring out where the bridge goes, using straightedges along the sides of the neck to get the L/R orientation, and an Ibex fret rule for the string length. Once I have it located, I clamp it dry and drill the two E string holes, then use these tapered bridge locating pins from StewMac for the glue up.

http://www.stewmac.com/shop/Tools/Special_tools_for_Bridges/Acoustic_Bridge_Locating_Pins.html?actn=100101&xst=3&xsr=1402

They have no slop, and they're made of HDPE or similar and are easy to remove after the glue dries.

Pat
Author:  Corky Long [ Wed Dec 15, 2010 1:31 pm ]
Post subject:  Re: Locating, aligning, and gluing bridges
JJ Donohue wrote:
1) Position bridge precisely using the saddlematic and tape in place.
2) Drill 1/16" holes through E and e. Fit holes with 1/16" pins or drill bit.
3) I use the SM bridge clamp. I drill holes in the clamp that allow the pins to pass through.
4) Warm up the bridge and spruce
5) Apply HHG, align with pins and clamp within 45 seconds
6) Clamp for 12 hours.



I follow the same process as JJ. Only difference is that I don't have a saddlematic, so I measure, then measure again, based on 12th fret distance x2 plus compensation to the middle of the saddle. I tape the front and back edge of the bridge, then I measure again, then repeat (the measuring) gaah laughing6-hehe ... I'm only kidding a little bit here.

So far my intonation's pretty good - the measuring's paying off.
Author:  sdsollod [ Wed Dec 15, 2010 1:34 pm ]
Post subject:  Re: Locating, aligning, and gluing bridges
I use Ken Cierpilowski's "Bridge Setter". It works well...


http://www.kennethmichaelguitars.com/
Author:  Bob Garrish [ Wed Dec 15, 2010 1:47 pm ]
Post subject:  Re: Locating, aligning, and gluing bridges
James Orr wrote:
I saw a picture on Hesh's site last night (http://www.lenaweelutherie.info/page6/p ... age21.html) that gave me a bit of an Ah Ha! moment.


I'm nominating Hesh for typo of the week. Start of paragraph, about 1/3 of the way down the page:

"Also consider that guitar tops are often doomed." -Hesh

Made my day :)
Author:  JohnAbercrombie [ Wed Dec 15, 2010 1:49 pm ]
Post subject:  Re: Locating, aligning, and gluing bridges
I don't use pins any more, though they work well.
I just make a little 'wall' around the bridge with layers of masking tape; it seems to be enough.
John
Author:  James Orr [ Wed Dec 15, 2010 2:26 pm ]
Post subject:  Re: Locating, aligning, and gluing bridges
Thanks guys. Extremely helpful.
Author:  Arnt Rian [ Wed Dec 15, 2010 2:33 pm ]
Post subject:  Re: Locating, aligning, and gluing bridges
JohnAbercrombie wrote:
I don't use pins any more, though they work well.
I just make a little 'wall' around the bridge with layers of masking tape; it seems to be enough.
John


That's what I used to do, because that is pretty much how Cumpiano shows it in his book. I now do it as Woody describes; Tracy's center line finder w/ bridge locator, 4 mm drill bits in E-string holes. I've had a couple of bad glue-ups with the SM bridge clamping caul (the jig that you attach with only one clamp, and then tighten a pair of screws over the bridge wings), plus I don't like the idea of pressing down those screws with only a caul underneath; too much risk for distortion. So I'm currently using 3 clamps, and I use hot hide glue for bridges.
Author:  Tom West [ Wed Dec 15, 2010 3:27 pm ]
Post subject:  Re: Locating, aligning, and gluing bridges
Bob Garrish: There have been times when I think that is the WRIGHT spelling... wow7-eyes idunno
Tom
Author:  JohnAbercrombie [ Wed Dec 15, 2010 3:30 pm ]
Post subject:  Re: Locating, aligning, and gluing bridges
Arnt Rian wrote:
JohnAbercrombie wrote:
I don't use pins any more, though they work well.
I just make a little 'wall' around the bridge with layers of masking tape; it seems to be enough.
John


That's what I used to do, because that is pretty much how Cumpiano shows it in his book.


That was the way Sergei deJonge was doing it a few years ago when I took a class with him.
I'm sure it's pretty common.
I've started gluing bridges with vacuum, so having pins would be a bit more tricky for me.

John
Author:  Arnt Rian [ Wed Dec 15, 2010 3:49 pm ]
Post subject:  Re: Locating, aligning, and gluing bridges
JohnAbercrombie wrote:
That was the way Sergei deJonge was doing it a few years ago when I took a class with him.
I'm sure it's pretty common.
I've started gluing bridges with vacuum, so having pins would be a bit more tricky for me.

John


The reason I stopped doing it is I have had bridges slide ever so slightly during clamping with this method. Granted, I didn't use that many layers of tape, maybe a few more would have helped, but the pins are less hassle for me. Plus, it makes removing squeeze-out much easier.
Author:  Imbler [ Wed Dec 15, 2010 3:50 pm ]
Post subject:  Re: Locating, aligning, and gluing bridges
John, I am planning to glue my bridge on using vacuum as well, but I had planned on using wooden pins, and pre-gluing them to the bridge through the saddle slot to avoid a vacuum leak path. Am I missing a problem, or would this work?
thanks, Mike
Author:  JohnAbercrombie [ Wed Dec 15, 2010 4:19 pm ]
Post subject:  Re: Locating, aligning, and gluing bridges
Imbler wrote:
John, I am planning to glue my bridge on using vacuum as well, but I had planned on using wooden pins, and pre-gluing them to the bridge through the saddle slot to avoid a vacuum leak path. Am I missing a problem, or would this work?
thanks, Mike


That should work fine, Mike.
I'd bevel the holes in the top a tiny bit to make sure that there wasn't any chance of glue residue around the base of the pin causing a problem.
Lots of (good) ways of doing most of these things......IMO
John
Author:  Terence Kennedy [ Wed Dec 15, 2010 4:23 pm ]
Post subject:  Re: Locating, aligning, and gluing bridges
I pin mine after location like JJ. Two 1/16" brads in the saddle slot. I used the StewMac clamp for a while but the problem is that when you tighten the wing clamps it can take pressure off the center if your center clamp is not 100% rigid. I had at least one bridge lift and went back to separate clamps on the wings
You hide glue guys--are you putting glue on both surfaces or just the top?
Author:  JJ Donohue [ Wed Dec 15, 2010 4:31 pm ]
Post subject:  Re: Locating, aligning, and gluing bridges
Terence Kennedy wrote:
I pin mine after location like JJ. Two 1/16" brads in the saddle slot. I used the StewMac clamp for a while but the problem is that when you tighten the wing clamps it can take pressure off the center if your center clamp is not 100% rigid. I had at least one bridge lift and went back to separate clamps on the wings
You hide glue guys--are you putting glue on both surfaces or just the top?


Both sides... I just spread it out on the bridge and lay down a few beads on the top and slap it together.

I also peel off the squeezeout after 15 minutes. Occasionally I loosen a clamp to get it all and then reclamp. After reclamping, I pull the pins.
Author:  alan stassforth [ Wed Dec 15, 2010 8:16 pm ]
Post subject:  Re: Locating, aligning, and gluing bridges
I'm kind of an idiot, but what I do is locate it with straightedges, and my fret ruler,
screw it down on the wings, remove the screws after glue up, and put a little paua
dot over the screw hole.
No way that's gonne move.
Plus, I like the dots.
Author:  LuthierSupplier [ Wed Dec 15, 2010 9:32 pm ]
Post subject:  Re: Locating, aligning, and gluing bridges
So glad to see everyone enjoying their CenterLine Finders! James, I do it the same as most here. I use the saddlematic to locate where the saddle will fall and add my compensation. Then I use my CL Finder with the bridge square attachment to get the bridge square and centered in relation to the neck. I then tape down the wings and drill 2- 3/16" holes in the 2 E string bridge pin holes. After I drill the hole, I leave the drill bit in and release from the drill. Then take another drill bit and do the other hole and then release it from the drill. So after the drilling is done I've got 2 drills sticking out of the bridge in the 2 outer bridge pin holes. At this point I check the saddlematic reading again and look at the guitars front from a distance to check alignment and see if it looks okay. If all is okay, I just lift the bridge off with the drill bits still in them and put the glue on the bottom and the guitar top. Put the bits into the holes in the top to locate it, then clamp using a ibex clamp in the middle of the bridge. Once the middle is clamped down, I remove the drill bits and then clamp the wings with 2 more cauls and clamps. Never had a problem with movement.

When I glued my little uke, I did the same thing except I drilled 2 holes on each end of the saddle slot(only 1/16"), but same sequence.

By the way, I used hide glue before and never had luck keeping it glued down. Probably user error. But now I just use titebond original and never had a problem.

Hope that helps! Good luck!
Author:  James Orr [ Thu Dec 16, 2010 1:06 am ]
Post subject:  Re: Locating, aligning, and gluing bridges
Seriously, lol. It sounds like I need to start using that feature of my centerline finder! And pins. Those two things should really curb my issues.
Author:  Alexandru Marian [ Thu Dec 16, 2010 2:55 am ]
Post subject:  Re: Locating, aligning, and gluing bridges
I have little faith in tape dams, no matter how tall; they are soft by their nature. A sliding bridge could distort these by a fair margin. Lately I rely on a straight edge clamped to the neck and referenced to the 12th fret, which stops in the saddle at the high E. The rest is done by 2 solid dams. All the surroundings of the bridge are heavily sealed with shellac anyway. On the right spot I put 2-3 layers of tape on which I superglue two spruce sticks, one at the back of the bridge and the other giving the bass length. It is much more solid than a tape dam and safe for the soundboard.
Author:  TonyFrancis [ Thu Dec 16, 2010 4:34 am ]
Post subject:  Re: Locating, aligning, and gluing bridges
-
Author:  Alexandru Marian [ Thu Dec 16, 2010 5:34 am ]
Post subject:  Re: Locating, aligning, and gluing bridges
Do you unload the entire brush (or squeeze out a lot from a bottle) or just paint the surface? It is a difference, I hope I am making sense. I guess that in the first case you get better temperature conservation and lots more squeeze out. That too much squeeze out drives me nuts especially when gluing braces. At the moment I have far better control with fish glue; with hide I am always afraid I did not put enough.
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