Pinless bridge troubles X30

byudzai · #1 02-23-2019, 04:51 AM

One of my strings keeps wanting to come loose from my pinless bridge. I threw it through a little washer for the moment, but I think I'm going to 3D print this part in aluminum and glue it under the bridge. Weighs the same as the 6 bridge pins supplied by Emerald. We're looking at it from inside the guitar, so the string will come down through the hole and then catch against the little ramp there. Thoughts?

kramster · #2 02-23-2019, 06:07 AM

Cool...great having a genius on here...saves me the trouble... nice wood floor by the way...wood or lament ?

jonfields45 · #3 02-23-2019, 08:36 AM

This guitar was originally supplied with bridge pins? It is the one where you've been inserting the bridge pins from inside?

new2guitar_eh · #4 02-23-2019, 08:41 AM

Seems a good approach. First however, have you asked Alastair about what is going on?

new2guitar_eh · #5 02-23-2019, 08:44 AM

Separate question...would such a part work on a non-pinless bridge too?

jwellsy · #6 02-23-2019, 09:18 AM

That's a great design effort. What CAD program do you use? I have a few regular PLA type 3D printers. I do see a couple of things you may want to think about.

The inside bevel where the string goes through the base hole appears to be backwards and may tend to cut into the string.

The gap between the uprights are currently the same for all strings. That measurement will be critical to accommodating various string diameters while excluding the eyes. The uprights may be a little stronger if those gaps were graduated.

I would add more meat to the forward side of the uprights. There's a lot of force pulling forward.

David Eastwood · #7 02-23-2019, 09:37 AM

I'm more curious about why one string keeps coming loose. What's different about the bridge in that position?

Methos1979 · #8 02-23-2019, 09:53 AM

Quote:

Originally Posted by eatswodo

I'm more curious about why one string keeps coming loose. What's different about the bridge in that position?

Same here. I have one string ball end that seats much lower than the others - see photo below.

Along with the slight PITA of getting it to come loose for string changes, I worry that this one might at some point wear farther (further?) and start to slip. Should this happen I would likely just send it back and have Alistair convert it to a pin type bridge (assuming this can be done) and also have the bridge tinted at the same time.

But I'm getting way ahead of myself. I've only done the one string change so far and don't do them all that often as I typically only change strings 3-4 times a year, if that. But I would like to hear more details about the how the slippage issue came to be.

steelvibe · #9 02-23-2019, 12:53 PM

Quote:

Originally Posted by kramster

Cool...great having a genius on here...saves me the trouble... nice wood floor by the way...wood or lament ?

I think it's Brazilian but maybe Emerald should make a CF version so that you can travel with it?

Gitaman · #10 02-23-2019, 02:09 PM

How about A dome with a center cut to make the two posts so that the string ball end stays secure.

with a big enough hole in the back for entry into the core.

Gitaman · #11 02-23-2019, 02:18 PM

or just curl the posts up and back like horns... All the way to the base leaving just enough space for the string to pass by. It will be tough to incidentally slide back out.

tommyld · #12 02-23-2019, 03:05 PM

Nice design...seems like it should work.

I've slotted wooden guitar's bridges using tabletop jigsaw blades (by hand)...maybe a slightly deeper slot would fix it. Though IMO, "stock" pinless bridges, especially with CF, shouldn't slip or fail ever. Have you contacted Emerald?

SpruceTop · #13 02-23-2019, 05:11 PM

Ovation has an excellent pinless bridge design. Never had one fail in owning many guitars of the brand over many years. Maybe Emerald could adapt a variation of the Ovation design?

byudzai · #14 02-23-2019, 08:31 PM

Quote:

Originally Posted by jonfields45

This guitar was originally supplied with bridge pins? It is the one where you've been inserting the bridge pins from inside?

This guitar has a dedicated pinless bridge. I think one of the slots just has bad geometry for some reason.

Quote:

Originally Posted by new2guitar_eh

Separate question...would such a part work on a non-pinless bridge too?

That's the hope! If it works I'll make a few different sizes for different pin hole spacings and put them on Shapeways in case anyone else wants one.

Quote:

Originally Posted by jwellsy

That's a great design effort. What CAD program do you use? I have a few regular PLA type 3D printers. I do see a couple of things you may want to think about.

The inside bevel where the string goes through the base hole appears to be backwards and may tend to cut into the string.

The gap between the uprights are currently the same for all strings. That measurement will be critical to accommodating various string diameters while excluding the eyes. The uprights may be a little stronger if those gaps were graduated.

I would add more meat to the forward side of the uprights. There's a lot of force pulling forward.

CAD program is Onshape. (Love Onshape!). The inside bevel is filleted -- see photo. Gap size shouldn't matter since ball size is equal; I suppose I could narrow them for the thin strings, but those have the least tension so prob doesn't matter. The bolsters supporting the ball-stops.... you're prob right about that, good call.

Quote:

Originally Posted by Gitaman

or just curl the posts up and back like horns... All the way to the base leaving just enough space for the string to pass by. It will be tough to incidentally slide back out.

Can you draw a picture of what you're describing so we can see it?

SpruceTop · #15 02-24-2019, 09:37 AM

Quote:

Originally Posted by byudzai

This guitar has a dedicated pinless bridge. I think one of the slots just has bad geometry for some reason.

That's the hope! If it works I'll make a few different sizes for different pin hole spacings and put them on Shapeways in case anyone else wants one.

CAD program is Onshape. (Love Onshape!). The inside bevel is filleted -- see photo. Gap size shouldn't matter since ball size is equal; I suppose I could narrow them for the thin strings, but those have the least tension so prob doesn't matter. The bolsters supporting the ball-stops.... you're prob right about that, good call.

Can you draw a picture of what you're describing so we can see it?

Although I love your elegant design and admire your desire to make and apply it to this problem, why not just use a thin copper or brass or aluminum strip or other thin material strip (maybe of a composite in keeping with the carbon-fiber/composite theme of your Emerald) with the six holes drilled in it for the strings to pass through and either just let the string balls draw it up against the bridgeplate or even use a little superglue to secure it in place for when you want to remove all strings from the guitar for cleaning? The strip could look similar to Taylor's string-ground strip with the wires and fuse removed, of course, and appropriate hole size and spacing for your guitar's needs.