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Demand for custom multi scale bridges?

Posted: Tue Jun 26, 2012 3:25 pm
by Dan Hehnke
I just wanted to run a little survey to find out what people think about this subject. I've started making most of my guitars with various multi-scale configurations, and it seems like more and more builders are starting to experiment with it as well.

I find the choice of bridges for this is rather limited. I usually like a simple tune-o-matic style bridge because it allows for the most possible configurations, eg you can use a Bigsby, do string through, put tuners on the bottom end for a headless, etc. So what I have done, and I've seen others do occasionally is machine a custom slanted base for use with typical adjustable saddles such as the ones you can pull from a Wilkinson roller bridge. It's cheap enough that robbing the saddles is well worth it.

It would be easy to make a 3d model of a custom bridge for CNC machining, and make it so it is easy to adjust the parameters for each one to fit the guitar. If I knew the FB radius, string spacing, and angle at the bridge.

I don't yet know how much it would cost to have one-offs machined, but I thought I'd look into it, possibly starting with brass.

Do you think there would be a demand for this kind of thing, if the price was comparable to other high end bridges?

Re: Demand for custom multi scale bridges?

Posted: Tue Jun 26, 2012 4:40 pm
by Dan Hehnke
I was thinking something along these lines.

Re: Demand for custom multi scale bridges?

Posted: Tue Jun 26, 2012 6:22 pm
by Jason Rodgers
When you say "demand," do you mean going into mini-production yourself and selling them? I don't know that answer. But in terms of bridge configurations, if you're going to go with the bridge base in the example above, or any bridge base that requires a different angle for different scales, I have a couple suggestions.

When it comes to multi-scale instruments, regardless of the treble and bass scales used, there will always be a difference between the two. For example, if folks are doing a standard 6-string, they might choose 25" to 25-1/2": if it's a baritone, it might be 26-1/2" to 27". Either way, the difference is 1/2". That can be a stock bridge configuration.

Of course, all this all depends on where people put the perpendicular (to the centerline) fret. In the 1/2" example above, if the nut is perpendicular, then all the difference is in the bridge. If the bridge is perpendicular, all the difference is in the nut. If the 12th fret is perpendicular, the difference is halved. If the perpendicular fret is at the 7th... etc... If you're offering an off-the-shelf product, though, you could possibly dictate a "best case scenario" to your customers and tell them to put the perpendicular fret at the X fret.

So what you might have to do is take poll of some of these parameters - scale differences and perpendicular fret - to find out what people tend to be using. You might find a lot of different ideas out there, but with that information, it seems that you could come up with a couple stock configurations that would accept a variety of scale differences. It might only end up being a small handful: maybe starting at 1/4" offset and going up by 1/8ths to a 1" offset (or some division that could accept scale differences one way or the other).

I've not played a multi-scale guitar, but I plan to build some. Even though they're starting to seem more "normal" to folks who pay attention to guitars, the general public doesn't really know why it's used. It might take Taylor putting a multi-string guitar out there for it to really catch on. As for small-time builders using it, the barriers created by the need to fabricate a custom bridge might be holding people back. If someone offered a stock bridge, maybe folks would be more willing to experiment.

Re: Demand for custom multi scale bridges?

Posted: Tue Jun 26, 2012 6:43 pm
by Dan Hehnke
I understand everything you are saying. And what you said about the perpendicular fret, combined with different scale differences is why I am going the way of a completely custom bridge, rather than off the shelf. I think you might be able to nail most configurations down with only a handful of configurations, but when you add in string spacing also, I am not so sure. What I was trying to say, was that it's very easy to adjust the CAD file for different configurations. And if I found a friendly machine shop, I would think it would also be just as easy for them to input the new CAD file. I'm sure there will be a setup charge, but not sure how much.

My feeling is that someone making an instrument that is custom enough that they are going to make a multi-scale design is going to want a bridge configuration exactly matching their design, rather than adjusting their design to match a bridge config. That's what I want, which is why I might have my own design machined.

Re: Demand for custom multi scale bridges?

Posted: Wed Jun 27, 2012 6:49 am
by JC Whitney
Shooting from the hip here: what if the two bumps/sides of your bridge above were able to pivot (and then be locked down) around the post holes to acommodate different angles during construction? Some sort of side to side adjustment would also be necessary to deal with the varying "width" of the saddles as their angle changed relative to the centerline of the neck. Hmm... I see it as two D shaped pieces sitting on the base plate, posts go through matching holes in both - as the angle changes the Ds' flat edges stay parallel. (o/------/o) (oI------Io) (o\------\o) A few allen screws to tighten everything down once it's configured.

Re: Demand for custom multi scale bridges?

Posted: Wed Jun 27, 2012 10:28 am
by Jason Rodgers
That's good thinkin', JC. So the base plate would be the variable part, which would be very simple to machine out of bar stock. And heck, unless the posts absolutely need to be 'D'-shape, they could just be cylinders. The bracket across the top, holding the saddles, would be a little more complicated, but simplifying the base of the bridge would mean less cost for the whole unit.

Re: Demand for custom multi scale bridges?

Posted: Wed Jun 27, 2012 12:26 pm
by Dan Hehnke
I like that idea. The problem I still see though, is the radius. The steps built into the main plate for the saddles to rest on are aligned parallel to the neck as well. It may be hard to get those to rotate along with the posts. I suppose if you made the saddles much thinner than typical, there might be room enough to rotate them without the steps being necessarily parallel. But the tapped holes in the base to secure the saddles would not be in the right place any more....hmm.

One other idea I did have was to get one long piece of brass machined with the steps in the right place and the posts as a long rail, and then I could just bandsaw out bridges at the angles I needed, then do the rest of the finish work. Of course then I'd still have to locate and drill and tap the saddle holes by hand.