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View Full Version : Bridge Clamping...your methods?



zdiver7
06-14-2010, 11:36 PM
Hi guys, just curious how everyone goes about clamping their bridge?

I was thinking about using Hana Lima's manual method of using 2 strips of wood wider than the lower bout with threaded rods in each end, and then using a raised(or lowered, since it's upside down :) ) section in the middle to actually apply the pressure on the bridge.

I also like the idea of using the 5" soundhole clamps from Stew-Mac since there will be squeezing pressure from both sides kind of sandwiching the bride and the soundboard, rather than just pressing down on the bridge like the Hana Lima method...

However, I really don't want to pay the 33 bucks plus shipping for 3 clamps from Stew-Mac. Soooo, how do you guys go about it? I am keeping my options open at the moment, until I get some feedback. I still have some time until I will be ready to actually mount the bridge...

Sven
06-15-2010, 12:00 AM
I'll copy-paste one of my posts on ukulelecosmos earlier this year:



Hope to stick the Bridge on before the weekend, any quick tips for getting it right?
1. measure the distance from the nut. If you want to compensate, don't forget that. I add 1,5 - 2 mm and then compensate the saddle some more for the C-string. So a scale length of "350 mm" gives me 175 mm from nut to 12th fret and 177 mm from 12th to saddle.
2. place a piece of masking tape at right angles from the centerline, between bridge location and sound hole at the measured distance. If you put the bridge on the top and it sits next to the tape strip, it should now be square and at the right distance. NB the tape mustn't be to sticky. Put it on your forehead or your trouser leg first, then on the uke. Or just buy the expensive blue tape.
3. Now the smart trick. Put a steel ruler along the side of the fretboard and mark a line on the masking tape. Do the same on the other edge. You should have two marks with the centerline in between, and the distance between them is a bit shorter than the length of your bridge.
4. carefully place the bridge in the right place, eyeing the pencil marks. This is easy.
5. place strips of masking tape at the ends of the bridge, and a strip at the end block side. The bridge can't move now, the tape forms a nice and snug little cradle for it.
6. Optional, but recommended. Remove the saddle and drill two small holes (1 mm) in the saddle slot straight down through the soundboard and patch. prepare two L-shaped pieces of steel wire (1mm diameter). I make them so the long ends stick out the ends of the saddle slot, but the short end shouldn't go down beneath the bridge patch - a c-clamp will always hit it in the uke and push it up.
7. Smear glue. Carefully fit the bridge between tape strips and make sure the steel wire hits the holes. If you use c-clamps (and I hope you do), fit one at the time and slowly increase pressure. There should be some glue squeeze out.
8. After 5 minutes carefully remove the tape and let that remove the glue. Remove the last glue with a piece of wood and lastly a damp piece of cloth.
9. Drink beer. Eat cheese.

Sven

With C-clamps from metmusic.com (called f-hole clamps):

http://4.bp.blogspot.com/_gXMDRA552Y0/S6VKUkw-ywI/AAAAAAAAA0M/CqB-PuN4UXk/s1600/bild-766528.jpg


With some masking tape showing, and my old home made clamp:

http://2.bp.blogspot.com/_gXMDRA552Y0/Sn8_EtfCMYI/AAAAAAAAAlc/Bv7peP-INWM/s1600/bild-702933.jpg


And with another clamp, and tape (I love my pics!)

http://1.bp.blogspot.com/_gXMDRA552Y0/STkuL34C6uI/AAAAAAAAAYY/RFhtPBe-q58/s1600/photo-743379.jpg

Allen
06-15-2010, 01:17 AM
I vacuum clamp all of mine on now, but have used various method from bridge clamps to go-bars with support inside. I've even done several with just a rubbed joint of hot hide glue. If your up on using hide glue, and have good mating joints, this method works really well.

Michael N.
06-15-2010, 01:48 AM
Hide glue, no clamps. Just light finger pressure for 3 or 4 minutes. Those 3 or 4 minutes can seem like an awful long time though.

Timbuck
06-15-2010, 04:06 AM
I vacuum clamp all of mine on now,
Do you leave the Vacuum pump running all the time while the glue set's?.

Moore Bettah Ukuleles
06-15-2010, 06:52 AM
You may find that the Stewmac 6" clamps are a bit too long. I can always manage to get one in the soundhole but three of them are pretty tight. And forget about it for anything smaller than a tenor. The metmusic 4" clamps seem to be a better fit.
http://www.metmusic.com/SearchByCategory.aspx?CategoryCode=TOOLCL

ksquine
06-15-2010, 08:57 AM
I like that home made clamp Sven. I might have to use that idea someday

fahrner
06-15-2010, 09:54 AM
I like that home made clamp Sven. I might have to use that idea someday
Yes, me too.
Sven, why did you stop using the home made one?

Allen
06-15-2010, 11:08 AM
Do you leave the Vacuum pump running all the time while the glue set's?.

I built a vacuum resevoir set up for all the tasks I use vacuum for. It's basically a reverse compressor. Pump attached to an old compressor tank with gauges and valves to turn it on and off when vacuum rises or falls outside of the set limits. Runs for about 1 minute every 1/2 hour when in use.

Bradford
06-15-2010, 11:31 AM
Bridge clamps are pretty easy to make. Here are a couple of mine, made of 1/2 inch round steel rod and 1/4 inch bolts. I used a Mapp gas torch to heat the rod to bend it, drilled and tapped the ends for the bolts.

Brad

Timbuck
06-15-2010, 11:54 AM
Have I ever shown this one before??...I can't remember if i did or not.
http://i219.photobucket.com/albums/cc143/shiregreenbod/PICT3946.jpg

zdiver7
06-15-2010, 12:15 PM
Man, all you guys are so crafty with your DIY bridge clamps! :) I think for now I will probably just buy those 4" F-Hole clamps from metmusic that Chuck and Sven linked to... a bit better priced than the bigger and bulkier Stew-Mac clamps!

Thanks for all the input guys!

erich@muttcrew.net
06-17-2010, 11:02 PM
I wanted to post this but didn't have the pics on my notebook and I had forgotten they were already in our album.

13787 13788

This is a little bridge clamping contraption we made to clamp bridges on without C-clamps. You feed two lengths of line through little 0.8 mm holes that you drill through the saddle slot and the top, pull them to the soundhole and through a small ebony bar and tie an 8 knot or a double hitch to keep them from slipping. Then you pull the lines up till everything is sitting square underneath and string the other ends through the "clamp" and onto the tuners. We used 28 lb fishing line to start with, but that snapped a couple times so we switched to a wrapped D steel guitar string and that works a charm.

I've done the 5 minute thumb clamp on pieces before, but never the bridge - I always thought clamping pressure was kinda sine qua non for the bridge joint. I'd like to be wrong here, but I don't know if I would trust a thumb-clamped bridge, even with hot hide glue, to hold the 20-40 pounds of tension on the strings.

Allen
06-18-2010, 12:28 AM
I'm using 315 gram strength glue for everything these days and its brilliant for rubbed joints. Test to destruction, the wood always fails before the joint.

I do love your solution though Erich. And it's one of those jigs that is a real conversation starter when you've got your mates over and having a look at all your kit.

Michael N.
06-18-2010, 03:00 AM
Rubbed joints with Hide glue work extremely well. Evidenced by some Lute makers who glue their bridges on in that manner. The large Baroque lutes have some 25 strings. giving a total string tension of around 90 Kg's. That's a lot of tension on a bridge that has a gluing surface area less than that of a Steel String Guitar.

Pukulele Pete
06-18-2010, 03:51 AM
What do you mean by " rubbed joints " ? thanks

Michael N.
06-18-2010, 05:49 AM
Place glue on one of the mating surfaces, place in position and rub the bridge (or whatever) backwards and forwards. In case of a bridge you go across the bout ie. opposite to the direction of the strings. Keep rubbing until the glue 'grabs' and locks. That's it. Hopefully it will be in the correct position.
I don't even do a rubbed joint for the bridge. I place small 'tabs' of masking tape (perhaps 4 or 5 layers thick) to locate the bridge position. Spread glue on the underside of the bridge. place and lightly press into position. Remove it after a few seconds and apply glue once again and relocate. Hold it with light finger pressure for approx. 4 minutes. Let go and carefully clean the squeeze out. You don't need heavy finger pressure and you certainly don't want to deform the soundboard. Glue needs to be of a certain consistency - neither too thin nor too thick. You can always practice these type of joints on scrap wood.