Official Luthiers Forum!

I've coined the term here "serviceability quotient" to refer to some measure of how serviceable an instrument was engineered to be. Of course in my business I want things engineered to be properly serviced as service may be expected to be performed on any wooden musical instrument.

So Epiphone's bridge design on their L-OO is so very poor that no one did a walk though before they produced these things and made sure that an owner could change a string..... They can't and this owner discovered that the hard way....

The pin recesses are so deep that you cannot get any of the various tools (we have them all and then some...) on the pin head because you are only working with less than 1/2 of the pin head exposed.

So.... to take the strings off I had to cut them off, all of them and stick my massive arm... in the sound hole and wiggle and push the pins up from in the box. I was swearing to beat the band this AM at 3:00 when I did this one....

Anyway after the new strings were on and it was in for a full setup I want to mill the saddle after taking measurements at the 12th. So..... that meant installing temp pins (my idea) on one side so I could pull them, take the saddle out, mark it, mill it, replace it, remeasure and if I nailed it slack the strings and replace my temp pins with the ****** pins that came with it.

Sheesh

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The name catgut is confusing. There are two explanations for the mix up.

Catgut is an abbreviation of the word cattle gut. Gut strings are made from sheep or goat intestines, in the past even from horse, mule or donkey intestines.

Otherwise it could be from the word kitgut or kitstring. Kit meant fiddle, not kitten.

Hesh... I know you're with me. You want to kill some of these people who make these things.

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"Act your age, not your shoe size" - Prince

Desperate times call for desperate measures.....

I guess they were thinking you only have to put strings on once in the factory.

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This thing sounded so bad they may be right....

I wish design flaws were found just in imports from China, but that same flaw - overly countersunk pins - is present on every <Super High End Builder Dude> and his apprentice's clones we saw come through the shop. We had a custom-ground set of Knipex end cutters just for those instruments. Other bridge design and execution flaws abound on factory as well as small shop and larger boutique builders... as should be expected given some builders see bridges as canvas for artistic expression and others as a functional bit of structure that makes the guitar go.

Years ago, I spent roughly an entire weekend fabricating and installing replacement bridges on two North American-built custom guitars... 0.085" worth of material at the treble side of the through saddle the root cause of bridge failure of both of the builder's guitars owned by our customer. Mr. Stock had a lengthy discussion with the builder on that design flaw, as well as other execution issues on finish and neck set. Based on a quick check of that builder's web site, those design and execution flaws still appear to be present after more than 5 years since that discussion.

As I heard far too often at that former shop, learning organizations require both willingness to accept critical, sometimes unkind review as well as willingness to wipe egg off face and make necessary changes to design, process, execution, etc. The related comment I heard was that those who won't or can't learn from failure - either their own/by others - really make life interesting for repair professionals.

In general, we saw better awareness of the consequences of design choices and more consistent execution in instruments from custom builders that had spent a lot of time doing repair work. Those builders without a repair background seemed less consistent in making wise choices in design for durability, as well as ability to offer effective warranty support. For those builders without a repair background, hiring a repair professional to handle warranty work is one possible solution... and one we wish we would have seen more of from North American small shop builders.

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A constellation only takes shape when one maps the whole.
- Beth Brower

Very good point Woodie. Some of the most egregious design flaws I’ve encountered while repairing - truss rod nut inaccessible due to bracing position, strings hanging up on their neigbour’s posts due to poor tuner placement - have all been on luthier-built instruments.

That’s not to say the big boys don’t have their moments. Plenty of time to ruminate on these things as you heat out the walnut plug on a modern Fender in preparation for practicing your proctological techniques on yet another stripped 1/8 hex drive…

Good Point Woodie, That is true in my case, Even though I am new to building (2 electrics and 2 acoustics) that is something that is always on the back of my mind when I am planning or building a guitar. I often have a problem with over-thinking stuff and delaying building something just to dot my i's and cross my t's almost to a fault...

Cheers,
Bob

Ain't that the truth

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Steve Smith
"Music is what feelings sound like"

Great post and again we see the recommendation that if you want to be a great builder or even be fast tracked to getting better doing repair work is an opportunity, an opportunity to learn to build... better. This was Rick Turner's RIP big point too when he was here only his delivery of the concept was not as palatable to all as your's is Woodie.

I learned some important things about my designs and practices as a builder too such as finish the instrument with the neck off. I also learned that frets are not something you bang in when you are close to being done with the thing and call it good... And I also learned that my own bridge design has a flaw in it too when it comes to using conventional clamping cauls the back pressure needs to be augmented. Another flaw in my Heshtone bridge design is how thin the wings are they won't do well if the bridge bottom has to be milled down for a bridge reglue. I have work arounds for all of these things but it would have been better to not be in this position at all.

My comfort level with HHG greatly increased too when I started doing repairs since I used it much more often.

Anyway thanks Woodie.

The builder who had the opportunity to heed some advice but stayed with the flawed designs is sad. They missed one of those opportunities that I am speaking of.

Leo Finder even got things wrong, some things. He was a master of manufacturability but did not get the guitar physics all that well. For example the standard Fender neck design engineered to use a certain sized piece of wood lacks proper break angle at the nut and has to be augmented with string trees, special short post tuners or both.

Gibson tremolos are very much an exercise in what were they thinking....

And Ov*tion, well make me puke......

The lovely thing about small shop constructed instruments is that the builder can be very agile with regard to change... there is a freedom there to immediately apply lessons learned which is usually lacking in a factory setting. Imagine the issues a large production builder such as Epiphone has in actually addressing a design flaw... developing the fix, documentation of the change, adjustments in the supply chain, changes in marketing and customer support materials, etc. - and that is before implementation on the production line. The truth is that we have some advantages in our small operations that the big guys envy.

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A constellation only takes shape when one maps the whole.
- Beth Brower

Very true and good point again Woodie. Epiphone produces in multiple countries too so there is that too in terms of change being slow and perhaps painful.

Going to take this a step further and suggest that people get repair experience BEFORE getting big time into building. Lots of the better mousetraps that I came up with were not better and I was not who came up with them I simply didn't know my guitar history very well when I started building. Would have been much more useful to see and know why some designs fail before attempting my own.

Had a small builder instrument in yesterday and it was typical with many of the same issues we see on most, not all small builder instruments. Fretwork, nut, saddle, set-up were all approached as if it wasn't expected to need to be done after the woodworking... and was an afterthought. It weighed a ton, had 7 different kinds of wood on it and not all matched, obvious major efforts to be different somehow from the others (differentiation) but with bad ideas. The saddle for example had the bottom scalloped.... WTH?

But when all was said and done frets were loose, action high, neck angle wrong, etc. Had this builder been in the repair business or sent some time in the trenches they might have had more knowledge to approach these operations with.

When a guitar fails at being a successful tool for a musician it's failed at being a guitar in my view.

The thread title lends itself well to a little deeper discussion on bridge design and utility.

Woodie quote - "some builders see bridges as canvas for artistic expression and others as a functional bit of structure that makes the guitar go."

...And most of us see it as both. Bridges, headplates and rosettes are three areas that can and do become something of a builders signature.

This is timely for me as I'm struggling with designing bridges for my current 3 builds. Shooting for something unique that also hits the sweet spot for all the maintenance issues that can come down the road.

To open up the playing field a bit, I'm seeing some really really nice looking pinless bridges on steel string guitars these days. Any of you folks doing lots of repair work seeing failures in that regard?

Still dreaming of an "easily" removable bridge, like bolt on necks, that's something to wish for.

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Brian R, Wood Mechanic
N8ZED

Build archtops.

Repair experience teaches you what doesn't work. Then all you need to learn is what does.

It always seemed to me that Ovation took some sort of perverse pleasure in flouting 'standard practice', evern aside from the Tupperware.

I post this often, but somehow the message has not gotten through as yet. British designer and wood worker David Pye wrote:
" Where the problem is old, the old solutions will nearly always be best (unless a new technique has been introduced) because it is inconceivable that all of the designers of ten or twenty generations will have been fools"

How about those Tacoma guitar bridges? Remember those?

I'm also very interested in pinless bridges and would love to hear from experienced repair folks.

I'm guessing that keeping the mass low is one of the fundamental challenges with pinless designs. I haven't heard of structural failures with them but then I'm not a very experienced repair person.

I'm in the repair camp, and it seems to me I see a disproportionate number of failing pinless bridges, even among those that are bolted on. Right now I have two in the shop. I can't see the point, really, and I suspect (some with better understanding of the physics involved may chime in on the subject) that the design might hinder proper top movement as well.


Pierre
Guitares Torvisse

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Pierre Castonguay

I've only built a few steel string guitars (mostly stick to nylon), but the ss "pinless" design that I like best is the Elliot design, which is really more of a permanent pin design than properly pinless. It makes setup less of a pain than most pinless designs as you can pop the strings on and off easily and I also suspect that there is less of a tendency for this design to peel than other pinless designs.

William

I spent some time looking for an "Elliot" design bridge. Elliot guitars.....etc without much luck.

Any chance you can link a picture or website or something. It sounds interesting and I'd like to see one.

Thanks

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Brian R, Wood Mechanic
N8ZED

Jeff Elliot, who is most well known for his classicals, came up with it for the harp guitar that his friend Sullivan made for John Doan. There was an article on it, the 'Sullivan-Elliot harp guitar', in American Lutherie some years ago. There are some good pictures of the bridge.

I've used this design on several instruments, as well as for tailpieces on archtops. The ball ends of the strings are captured in holes on the bridge surface. The holes are drilled at a back angle so that tension on the strings pulls the ball further in, with it's top is more or less level with the bridge top when it's seated. The strings have to be ramped down into the bridge top. I have used short lengths of brass tube, inlet into the holes, and slotted for the string, for the ball to bear on, to avoid wear on the wood. The hole in the ball fits over a small pin (I use 1/16" brass rod) to keep the ball from flipping sideways: the pin is not there to take the tension; that's what the brass liner is for. String replacement is easy: once you slack them off they just pop out, and putting on the new string only requires that you use a finger on the ball while you start to tighten it, until it seats.

One big advantage of this design is that you don't run the risk of drilling a pin hole through a brace.

Some computer modeling that I've seen suggests that the load peeling the bridge up is no greater with this design than a regular pin bridge. My repair experience suggests that these bridges should be no more prone to pull up than a pin bridge. Pins may, however, help to retain a bridge that is loose for a while; keeping it from flying off catastrophically and killing the cat. That benefit is probably at the cost of more distortion in the top and bridge, however.

Thanks for the great description Alan. After reading it, I'm pretty sure I've seen pictures of the technique, they just weren't attributed to Elliot.

I always figured there must be some mechanical advantage to both well fitted bridge pins and the strings being wrapped over the top of the bridge and anchored against a solid bridge plate beneath in regard to holding the bridge down. Kinda like a tiedown strap over a load in a truck.

On the other hand, the high tension strings many classic players prefer approach steel in pull on the bridge.

Thanks for you post Alan, appreciated!

Back to the drawing board.

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Brian R, Wood Mechanic
N8ZED

Here's a link to Jeff's steel string bridges. The first two are traditional pin bridges. Past those are his pinless design ones.

https://www.elliottguitars.com/bridges1.html.

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formerly known around here as burbank
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