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I was talking to a friend today and he suggested I could make a string through acoustic bridge that would not require a bridge pin (small holes drilled at the tail of the bridge where the strings would go through) to avoid bridge pins but also avoid the damaging effect of the string balls on the bridge plate. Is there any design considerations when doing this?

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Tai Fu buddy here is a link to one discussion in the archives about pinless bridges: http://luthiersforum.com/forum/viewtopic.php?f=10102&t=13870&p=195397&hilit=+pinless+bridge+#p195397

There are many more too - if interested just search under "pinless bridge" in quotes and select the "archive" as the forum to search.

Good luck.

Great question Tai.

Thanks Hesh for the link.

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Jack Batts Maker and Repairer of Fine Violins

The archived discussion talks about this a bunch, but the main consideration is the increased tendency for the bridge to peel off. For that reason, i think they are kind of lame.

Of course, pin bridges also lift over time, and damage the bridge plate as they go.

Either way works, i would recomend removing the finish from the entire bridge outline before glueing, dont leave finish under the bridge perimeter. (i think that is good advice for pin or pinless bridges, but especially pinless)

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Jordan Aceto
Ithaca, NY

I wouldn't worry too much about a pinless bridge pulling off. FWIW, I bought a Harmony Sovereign with a pinless bridge in 1967 when I was 20 years old. For the next 20 years I subjected that guitar to a lot of rough treatment, but the bridge is still on there.
Walter

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Walter Lay
"It's taken me so long, but now that I know
I can see. All that I do or say, is all I ever will be"
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Well I would take a more skeptical approach. I have repaired way more guitars with pin less bridges (pin less that are not directly tied back to a bridge plate) lifting off than pined. There is a reason they are at a higher risk of failure. With a pined bridge the ball of the string pull against the bridge plate putting the glue joint of the bridge to the top in compression load. On a typical pin less bridge to top glue joint is more in shear load. If the guitar see some extreme heat like a summer time trip in the trunk of a car where the temps can easily reach 140f, the glue joint can succumb to the shear load. Now if your guitar will never see any thing like that (and it shouldn’t by the way) it is certain that a pin less bridge is at a far higher risk to fail at the top to bridge joint than a pinned bridge.

Now there are several methods of fabricating pin-less bridges that take this in to consideration and fabricate in a way that shares part of the added shear load into compression loading by means of attachment to the bridge plate with bolting and such.

Ask Ovation why they leave the mounting/allignment bolts in their pin-less bridges after glue-up

I'm 99% confident that George Lowden does not use pin keepers in his pinless bridge design. And you don't hear to offten of one of his bridges lifting or coming off.

Many of the lower quality companies (Takamine) actually bolt there pinless bridges onto the guitar top (along with glue). Than they put a plug in the bridge over the bolts.

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To continue the thought process then, what are the thoughts on bridges being bolted, either pinless or pinned? I know it's considered low-class these days but bridges were often bolted as well as glued in the past. You know, back when they weren't afraid to drill a hole in the top, bridges, pickguards etc.

So, what is the thinking?

Thanks,
Joe

There are examples of bridges which have been attached to their respective top for well over 60 years now. I think glue is fine. No bolts required.

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"There's really no wrong way, as long as the results are what's desired." Charles Fox

"We have to constantly remind ourselves what we're doing....No Luthier is putting a man on the moon!" Harry Fleishman

"Generosity is always different in the eye of the person who didn't receive anything, but who wanted some." Waddy Thomson

Be assured of that 99%, Rod. He's been using "bolt-less" pinless bridges for decades. It's worth reading George's thoughts about pinless bridges in the "Cult Of Lowden" discussion groups. A lot of careful thought has gone into the design to prevent bridge failure.

hi Tai
Rod & Sam are correct, my 25 year old Lowden bridge is still where it should be, and it look’s like its “stickin” around for some time to come. That’s on a cedar top 25.5 scale and I’ve used 13 to 56 gauge strings all that time.
I’ve wondered what glue / procedure he uses as I would like to try something similar on a S/S.
yours Geordie

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It's important to distinguish between whether something is a bad design, or just an opportunity for ineptitude to shine. I think pinless bridges fall into the second category. They're an opportunity to show if you have sloppy joints, bad gluing or clamping technique, don't know which glue to use where etc etc. Pinless bridges are less fool-proof than pinned bridges, that's all.

How many times do we see people complain on forums that totally standard procedures in guitar building (which have worked, repeatedly, for others) must be flawed because they've failed at them? My rule is if someone else has succeeded (take Lowden, in this case), then if I fail then it's not the designs fault!

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Bob Garrish
Former Canonized Purveyor of Fine CNC Luthier Services

I'm working on a Jeff Elliott design pinless bridge now which is what you call the Doolin design.
My J45 is 9 years old and is called an Early J45 and it's bridge is glued down an also is bolted down with what looks like 6-32 bolts . the heads are covered with the pearl dots on the bridge. It's my best sounding guitar so I don't think the bolts are effecting it any.

Tai Fu,
Are you referring to the type of bridge where the the ball end of the string is inside the box and the string passes through a hole in the bridge just big enough for the string to fit through? I built a ukulele this way and it worked great. Getting a steel string through a hole on the inside of a guitar could be quite a challenge.
Doug

Check Hesh's Link and you will see both types.

Bolts in bridges = not cool. The problem is that they do not stop the bridge from lifting, but they do make a royal mess of the bridge plate when the bridge does start to go. I see bolts that just eat their way through a bridge plate, making for an unfun repair.



I like that rule.

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Jordan Aceto
Ithaca, NY

I've made two guitars with pinless bridges. I'm back to pinned. I'm not worried about them coming unglued (I agree with Bob's observations), but there's a big disadvantage to pinless that is enough of a reason for me to not do them any more. That is, when working on the setup, you cannot disconnect the strings from the bridge without taking them off completely, since they have to be threaded through the holes in the bridge. On a pinned bridge, you can just loosen the string, pop the pin, and pull out the string, leaving it attached to the tuning machines. Makes some setup operations a lot quicker. The Elliot/Doolin design takes care of that, and is a cool design, but I don't like the looks of it.

I had originally had this thought that pinless bridges reduced mass by eliminating the pins, but I think (admittedly, I haven't actually measured this) the added mass of the larger tie-block required on a pinless more than defeats any gain.

Pinless bridges are kind of elegant in a way, but I actually like the shapes I can do with a pinned bridge better, without having to incorporate the tie block portion.

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Todd Rose
Ithaca, NY

https://www.dreamingrosesecobnb.com/todds-art-music

https://www.facebook.com/ToddRoseGuitars/

Many guitars with pinless bridges get quite worn behind the bridge with time. Lots of oportunities for the strings to scratch the finish when they break or get changed.

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Rian Gitar og Mandolin

hi
Arnt as you can see this guitar has been played, for twenty + years and
I have not found a problem with strings marking behind the bridge.
Geordie

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To Todd's comment about having to take the strings out of the bridge. I have seen pinless bridges with slots, so the strings can be removed.

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Jordan, thanks for the informed reply about bolts in bridges. I know you rarely see it these days, but have seen it on many old factory guitars, probably lower end models. Nice to hear the experiences from the repair end.

Joe

I have a related question (and I'll freely admit I'm pretty ignorant about flot tops): On those designs where all parts of the string are ABOVE the top, why is a bridge plate even necessary? Obviously, some alternate form of bracing would be necessary on the underside of the top, but why a traditional bridge plate? Just asking...not advocating! Thanks.

Patrick

It is a method of doubling the thickness in that area and helps convey the energy into the X-brace.

Patrick, you'll find plenty of disagreement on that question. Personally, I think a bridge plate is still a good idea, largely because I believe it creates a much more stable substrate for the bridge, i.e. it stiffens the area and helps limit cross grain wood movement (expansion and contraction of the spruce with changes in humidity) of the top, which helps ensure that the bridge will stay on over the years.

On the two pinless bridge guitars I made, I used a spruce bridge plate.

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Todd Rose
Ithaca, NY

https://www.dreamingrosesecobnb.com/todds-art-music

https://www.facebook.com/ToddRoseGuitars/

I have an acoustic bass guitar plan that has a rather simple pinless bridge. It is constructed the same as a pinned bridge but the pin holes are drilled at a 15 degree angle, the top of the hole being tilted to the tail of the guitar. The bridge is slotted as one would do for unslotteed pins and the pins are eliminated. I have yet to build one of these. Is there a flaw to this solution? Perhaps a reason it would work on a bass and not a standard six string?

Steve