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| Author: | Josh H [ Mon Apr 01, 2013 9:05 am ] |
| Post subject: | Classical Bridge Design |
I'm in the process of finishing up my first classical and have been looking at different bridge designs. I've been planning to go with a fairly traditional style, but I've come across pictures that show bridges with multiply holes for each string. These bridges usually allow the string to be tied off in a neater fashion than a traditional single hole design. Is there anyone out there doing these multiple hole classical bridges that can give me some insight into their design? I've searched around the internet, but other than finding pictures I haven't been able to find any additional info on making them. Thanks Josh |
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| Author: | Michael.N. [ Mon Apr 01, 2013 9:20 am ] |
| Post subject: | Re: Classical Bridge Design |
Lot of makers now doing the 12 or 18 hole design. There really isn't a lot to them, just all the extra holes. I guess you have to be mindful of drilling them too close to each other and that all the holes have to exit above the Bridge trough. That's about it. There's not a lot wrong with the traditional way of tying the strings though. Learn how to tie them neatly and they look fine. They also don't look like they have been infested with the dreaded woodworm. |
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| Author: | WaddyThomson [ Mon Apr 01, 2013 9:39 am ] |
| Post subject: | Re: Classical Bridge Design |
Here is how I do it. I made a plexiglass template, and use a Model Makers Center screw to make starter holes @ 1/16". I do it after radiusing the bottom of the bridge blank and before cutting out the slots for the saddle and the separation at the tie block. I also make a cut along the back of my bridges to leave a little lip below the string holes. I do all the slotting with a Radial Arm Saw. The holes are slanted to exit a bit higher in the other side of the tie block. Each hole is chamfered on both sides with a little Dremel V bit in a pin vise. Attachment: P1050038 (E-Medium).jpg Attachment: P1050044 (E-Medium).jpg
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| Author: | Colin S [ Mon Apr 01, 2013 9:42 am ] |
| Post subject: | Re: Classical Bridge Design |
I switched originally to the 12 hole bridge after going to Siguenza, but now have used an 18 hole one for the last 20 or so guitars, and much prefer it. The main benefit is the better break angle as the string isn't being pulled up by the overwrap. I use a bone plate on the rear of the bridge which stops the strings cutting into the wood of the bridge. I have a template I use to drill the holes. As Waddy says drill the holes before excavating the trench.  Colin |
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| Author: | Tony_in_NYC [ Mon Apr 01, 2013 9:44 am ] |
| Post subject: | Re: Classical Bridge Design |
What is the benefit of the multiple holes? I learned how to tie my strings just by copying the strings I was removing. Since I no longer own a classical, I would not be able to tie them if I needed to, but if I had a pic, I could just copy that. Does having multiple holes allow you to NOT tie them? Waddy, can you show a pic of your strings tied on your bridge? That is an impressive amount of small holes in a tight area by the way. |
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| Author: | Stephen Boone [ Mon Apr 01, 2013 10:03 am ] |
| Post subject: | Re: Classical Bridge Design |
As Colin said the main benefit is the break angle over the saddle. I use a 12 hole design and I can say for sure that string changes are much much faster at the saddle end. Attachment: IMG_5035editedraw.jpg Attachment: IMG_5047editedraw.jpg
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| Author: | jfmckenna [ Mon Apr 01, 2013 1:06 pm ] |
| Post subject: | Re: Classical Bridge Design |
I have a hard enough time drilling six holes 
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| Author: | WaddyThomson [ Mon Apr 01, 2013 2:06 pm ] |
| Post subject: | Re: Classical Bridge Design |
Colin's is similar to mine. He just puts the bone layer on there to protect the wood. I just like that I don't have to put any protection on the tie block, and it looks very neat with no strings crossing over. Now, if you have some guy tie them the wrong way, it dents the tie block(DAMHIKT). I actually find it easier to tie this way, once you have done it one time. I always supply instructions for tying with the guitar. Seems difficult, but it's very simple. |
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| Author: | ernie [ Mon Apr 01, 2013 2:26 pm ] |
| Post subject: | Re: Classical Bridge Design |
Stephen /waddy Have yet to build an 12 or 18 holer bridge . If you drill the holes before excavating the trench. How high up from the bottom is the lowest hole 1/8in ??? ernie thanks |
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| Author: | Jeff Highland [ Mon Apr 01, 2013 3:11 pm ] |
| Post subject: | Re: Classical Bridge Design |
Besides an improvement in break angle with 12 and 18 holes, the 18 holer also has the advantage of eliminating string dings in the soundboard from a slipped string end whipping over the tieblock |
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| Author: | Clay S. [ Mon Apr 01, 2013 4:18 pm ] |
| Post subject: | Re: Classical Bridge Design |
If the break angle over the saddle is a big concern you could just tie a knot in the end of the string before you slip it through the hole.  It might look a little messy though 
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| Author: | Mike Collins [ Mon Apr 01, 2013 6:06 pm ] |
| Post subject: | Re: Classical Bridge Design |
I use a 12 hole for "Flamencos" 18 for Classicals. The breakover angle is great Because of this I can make a lite in weight bridge with a lower profile(height) This helps me achieve the "sound-tone" that I 'm hearing in my ears & need to hear from my guitars. Plus the ability to get the string height(from the top) right for the player. It's a matter of personal choice . Mike |
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| Author: | WaddyThomson [ Mon Apr 01, 2013 7:42 pm ] |
| Post subject: | Re: Classical Bridge Design |
ernie wrote: Stephen /waddy Have yet to build an 12 or 18 holer bridge . If you drill the holes before excavating the trench. How high up from the bottom is the lowest hole 1/8in ??? ernie thanks I angle the bridge when drilling the holes so the bottom holes pop at as close to 4 mm as possible, so it's about a 2 mm slant in a 10mm tie block. Took some experimenting to get it right. However, if they come in low, I just chisel the channel a bit deeper to accommodate them. The goal, however is to have them just pop through at the height of the bridge wings at about 4mm. |
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| Author: | ernie [ Mon Apr 01, 2013 8:42 pm ] |
| Post subject: | Re: Classical Bridge Design |
Guess your doing it on angled drill press guide?? |
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| Author: | WaddyThomson [ Mon Apr 01, 2013 9:35 pm ] |
| Post subject: | Re: Classical Bridge Design |
Actually, I have a piece of mdf cut at an angle that I mount the bridge on, and ride that against a fence. Attachment: P1060252 (Large).JPG Attachment: P1060253 (Large).JPG
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| Author: | Josh H [ Mon Apr 01, 2013 9:48 pm ] |
| Post subject: | Re: Classical Bridge Design |
Thanks guys, this has all been extremely helpful and informative. Is there anyone who can post a top view of an 18 hole bridge (with the strings on) that would allow me to see the strings coming out of the block as they go over the saddle? |
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| Author: | enricopg [ Tue Apr 02, 2013 12:15 am ] |
| Post subject: | Re: Classical Bridge Design |
In my building experience I moved back and forth from 6 to 12 holes. I still have not found any pratical benefit from the extra holes. Moreover it happened more than once that traditionalists classical guitar players are puzzled by the steep angle. It happened that they untied the strings and tied them again using only 6 of the 12 holes. They feel like the steep angle gives them some unwanted tightness of the string. I never believed this. Nowadays if I make the 12 holes is just because it's easier to do before rather than after. But what I know for sure is that great guitars were built in any possible systerm. Did you guys find any qualitative difference by tying the string in 6, 12 or 18 holes? |
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| Author: | WaddyThomson [ Tue Apr 02, 2013 2:12 pm ] |
| Post subject: | Re: Classical Bridge Design |
Josh H wrote: Thanks guys, this has all been extremely helpful and informative. Is there anyone who can post a top view of an 18 hole bridge (with the strings on) that would allow me to see the strings coming out of the block as they go over the saddle? This isn't just of the bridge, but here you can see the break angle. Attachment: P1060798 (Large).JPG
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| Author: | Colin S [ Wed Apr 03, 2013 9:55 am ] |
| Post subject: | Re: Classical Bridge Design |
Waddy beat me to it! Here's another shot, again the whole body, but shows the break angle.  Colin |
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| Author: | dberkowitz [ Thu May 12, 2016 10:26 am ] |
| Post subject: | Re: Classical Bridge Design |
What is the typical offset for a 12 hole and 18 hole bridge? |
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| Author: | david farmer [ Thu May 12, 2016 11:22 am ] |
| Post subject: | Re: Classical Bridge Design |
When I'm retrofitting a six hole for 12 to increase break angle, I move the second hole centerline laterally 3mm and up 1.5mm relative to the centerline of the original hole. Hope that helps. |
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| Author: | Alan Carruth [ Thu May 12, 2016 4:02 pm ] |
| Post subject: | Re: Classical Bridge Design |
All of this is interesting, but break angle is not usually a problem on guitars. I've done a pretty thorough experiment on this, and found that once you get past 'enough' break angle, more doesn't help the sound. You can discuss just what 'enough' is, of course. In my experiment I used a mechanical plucker to get the same force and direction of pluck in the same place every time. I used a 'vertical' pluck; one that gave an initial displacement of the string that would leave it vibrating in a plane perpendicular to the soundboard. This gives the greatest driving force on the top. What I found in my experiment was that for this type of pluck 6 degrees of break angle was sufficient to avoid problems, although probably only just sufficient. Careful listening tests of recorded plucks, as well as objective measurements of the sound output, showed no significant change in the way the guitar worked when the break angle went from 6 degrees to 25 degrees. In most cases you end up plucking the string at least partly crosswise, so there are both vertical and horizontal components to the motion. In that case the horizontal motion could cause the string to roll a bit across the top of the saddle, and this might have an effect on the sound. More break angle would help to control this, but without data I can't say how much would be required. I suspect anything beyond about 25-30 degrees is overkill, though. The greater the break angle the more tipping force there is on top of the saddle trying to break out the front of the bridge. In the extreme case where the strings made a 90 degree break angle, running down the back surface of a vertical saddle, the tipping force would be equal to the tension on the strings. Tilting the saddle back is one well known way to solve this problem; if the saddle bisects the break angle there is no net tipping force on it, and it won't break out the front of the bridge. This does NOT affect the string forces driving the top, only the static forces trying to break the bridge. As always, one of the first things you learn when you do an experiment like this is that you should have spent three or four times as long and done a better one. Any experiment can only speak to the things that were done in that study, and it may be that I missed something important. At he moment, however, in the absence of better data, I'm sticking with the results I have: break angle probably doesn't matter beyond a certain point, and that point is 'way short of the extremes some folks are going for. |
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| Author: | Woodie G [ Thu May 12, 2016 5:40 pm ] |
| Post subject: | Re: Classical Bridge Design |
We do 4-5 six-to-twelve hole conversions a month - usually to increase break angle, but sometimes because the owner finds string changes to be less of a chore. While neither I nor the boss hear all that much difference in the conversions, both students and instructors prefer the modified guitars, and string changes are a bit easier. I should mention that these are almost always 3/4 and 7/8 sized guitars, although every few months we rework a full sized instrument. To perform the modification in place, we drill an offset hole at each string position, usually 5/32" over and 1/16" above, slightly angled as needed to stay below the trim on the block, using one of two long drill bits. An piece of old saw plate and a wood wedge are used to prevent damage to the area under the saddle. The drill bits used are either 12" flexible aircraft drill bits or shop-made extension bits using aluminum tubing and ends fashioned from quick-release, hex type bits. We don't really see any disadvantages to the modification, but we also don't find there's often a good acoustic argument unless the instrument has break angle issues which cannot be resolved with a little change to the owner's restringing technique. We usually recommend the mod when the measured break on any single, properly installed string is 5 degrees or less, and where the bridge is not otherwise compromised. With restring, this is about a 30 minute task when it's done by someone familiar with the job. |
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| Author: | david farmer [ Thu May 12, 2016 6:52 pm ] |
| Post subject: | Re: Classical Bridge Design |
I only do this modification to stop buzzing on the saddle when action is lowered. Not for any attempt to improve tone. Teaching how to tie a twelve hole so "carbon" trebles don't slip, I find, is more of an educational challenge than a traditional 6 hole. |
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