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Author Topic: bridge ramping depth  (Read 53 times)
Gottaplay
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« on: August 12, 2019, 12:45:38 PM »

Finally tackled my first ever fret levelling and action lowering DIY project and it was mostly fun. My 2008 L-03's PO had dried it out severely. When I bought it three months ago it came with two filled and cleated soundboard cracks running from the near the bridge back to near the tail. While the neck was fairly straight and the action tolerable at 8/64 E and 7/64 e I discovered afterwards that the neck angle had also been compromised by being dried out or at least that's my premise. A strait edge placed on the fretboard runs into the bridge about 1mm below the top. To my surprise the same can been said of two other brand new Larrivee's I sighted down at a local shop so go figure maybe that how L rolls??

 But I digress mainly the sound vs cost was what hooked me. I was after a player not so much a looker. Last month we did a blindfold AB test putting it up against my lady's father's D-10E which has been referred to at bluegrass jams as a "real cannon". Well I could hear the volume and sustain differences (closeish but not quite) and subtle  tone variations but my $750 L-03 held up quite favourable overall which felt pretty good and reaffirmed my investment choice.

 OK fast forward to taking 1/16th off the saddle and a full fret leveling,crowning and polishing and voila the better action and overall playability improvements. The Bridge untouched thus far by me is 8.2mm above the soundboard and I can't tell if it has already been shaved but I guess I could drop it another 1.2 down to Matthew Larrivee's recommended safe minimum of 7mm in order to gain more bridge clearance and breakover but then I`d have to ream the peg holes a bit as their already a tad snug and not perfectly even. Been reading a ton of info on ramping the bridge to get the saddle breakover angle back up to the minimum 15 degree for volume, sustain and clarity. The one specific detail I can't seem to locate is the maximum depth recommended for string ramps in the peg hole. Saddle height is now down to about 1/16" above the bridge in order to get the action down to 5.5/64 E and 3/64 e with .011" neck relief. In doing so the guitar now plays great but the breakover varies on the B compensated Tusq saddle from between about 9 and14 degrees with the high e being the shallowest as expected.

I`ve read and watched enough well informed luthiers to be confident in doing the ramping but have yet to read if there is a rule of thumb/best practice as far as how deep to set the ramp end into the peg hole wall. Off the top of my head somewhere around 1/2 the total depth of the ebony bridge seems reasonable but only if required.

And finally here's my question....can folks out there refer my to readable or watchable information sources regarding ramping technique and specifically maximum depth. Thanks

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jpmist
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« Reply #1 on: August 12, 2019, 08:28:32 PM »

Congrats on the find and willingness to salvage an old Larrivee. Considering it's age and dry history, it's no doubt fully opened up.

Only here to offer this site from Frets.com http://www.frets.com/FretsPages/Luthier/Technique/Guitar/Bridges/StringRamps/stringramp.html

"I try to make the most shallow ramp I can" - he  seemed to have just eye-balled it with a dremel which considering his experience he can get away with.

If you can spare the effort to record it, it'd be interesting to see if there's an audible difference in the shaved bridge compared to stock. My on-line diploma in armchair luthery suggests a lighter saddle will change the tone some due to less mass on the soundboard? - I'm guessing a sharper attack and more treble?

Good luck with the project!
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« Reply #2 on: August 12, 2019, 09:47:03 PM »

Hey JP thanks for the input. Given the shallow angle presently I`m guessing a deeper than typical ramp is needed but this is all new to me. Frets.net is one of my "go to" info sources thanks to it being brought to my attention by several members of this forum...tons of good info all in one spot..quite generous really.

Good idea on recording it pre and post ramping. I`ll let you know how it compares but not being very computer savvy I may be "challenged" in posting sound recordings. Just a simple country carpenter don't cha know.
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« Reply #3 on: August 12, 2019, 11:16:26 PM »

just found this:

That post was from me, Al.
Here is the info in more complete form:

This is an excerpt from what was posted on AGF a few years ago regarding break angle.
The response was from Alan Carruth , a highly respected luthier who has done rigorous testing and published results in luthier magazines on numerous aspects of guitar tone including sound ports and break angles.

The Question: Is it true that increasing the break angle over the saddle will increase the volume of the guitar? I would think that more pull would cause the top to vibrate more and produce better tonality.

The Answer: Not Really. The break angle isn’t what increases or decreases the pull on the top. The distance the strings are above the top changes the pull.

Take two otherwise identical guitars. One has a bridge that is .250 inch thick and the saddle is .175 inch above the bridge. The bridge pins are in a straight line behind the saddle. The break angle is uniform for each string and pretty steep due to the height of the saddle. But the torque the strings put on the top isn’t that much because the top of the saddle is only .425 inch above the soundboard.

On the second guitar, the bridge is .375 inch thick and the saddle is only .125 inch above the bridge. The bridge pins are in a smiley pattern, like a lot of builders use, so the break angle is fairly shallow and not uniform. However, this guitar sounds a lot fuller, louder, more resonant, and is more responsive because the torque exerted by the strings is greater. Why? Because the top of the saddle is .500 inch above the soundboard, giving the strings more leverage to work the top.

One can get too high. I’ve found that at about .550 inch, the tone gets muddy because the top is stressed too much.

I hope I’ve explained this in a way that makes sense. This doesn’t mean that a guitar won’t sound good with measurements differing from those above, but break angle, within a range of about 10 to 45 degrees won’t make any difference. If it did, all of the guitars with smiley bridges would sound bad.

There is much concern about break angle, widely disseminated on the web. But it is one of those urban myths. As long as the saddle is held firmly in the slot, you are o.k. The true key is the torque that the strings put on the top (height above the top), not what happens behind the saddle.

Well go figure...
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« Reply #4 on: August 13, 2019, 12:52:36 AM »


The Answer: Not Really. The break angle isn’t what increases or decreases the pull on the top. The distance the strings are above the top changes the pull.

There is much concern about break angle, widely disseminated on the web. But it is one of those urban myths. As long as the saddle is held firmly in the slot, you are o.k. The true key is the torque that the strings put on the top (height above the top), not what happens behind the saddle.


Well go figure...

That makes sense. I was a tad skeptical about being really precise with the ramp slots.  The end of the string is gonna vibrate the top the regardless of the break angle, but I didn't factor the overall height of the string acting as kind of a lever on the top.
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Larrivee OO-05 • Larrivee OOV-03 Short Scale • Taylor 322ce    Various Strats • Soundcloud https://soundcloud.com/jpmist
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