Help me modify a guitar capo
January 7, 2022 8:55 PM Subscribe
In order to play a particular arrangement I came up with, I need to modify a capo that I have, and I need any tips the hive mind can muster.
I got a 6-string gliding capo for my 7-string guitar, and spent a lot of time arranging a tune that is only possible to play with the capo. Once I started practicing it on my seven string, I realized that when I move the capo up mid-tune, the top string falls out of the rubber roller's range, making it impossible to continue.
I called the company, and they said that they were considering making a wider 7-string capo prototype, but then when I followed up with them a couple of months later, they said that they had scrapped the idea, so I'm out of luck.
But I don't want to give up on this. When you look at the design on that link above, you can see that the part that touches the strings is a rubber roller skewered and glued to a metal rod. There is a little space on either side of the roller, where I could potentially add some more rubber. Another possibility would be to replace the roller entirely.
So, I guess my question is: how would you proceed? It seems like I would have to do my best to match the rubber with the same density of rubber that is on the roller now, but I don't know how to begin (I have determination but admit to iffy skills in the diy maker department).
Oh, and the song is a 7-string solo instrumental arrangement of Stereolab's blips, drips and strips. It has already taken me months to get this far!
I got a 6-string gliding capo for my 7-string guitar, and spent a lot of time arranging a tune that is only possible to play with the capo. Once I started practicing it on my seven string, I realized that when I move the capo up mid-tune, the top string falls out of the rubber roller's range, making it impossible to continue.
I called the company, and they said that they were considering making a wider 7-string capo prototype, but then when I followed up with them a couple of months later, they said that they had scrapped the idea, so I'm out of luck.
But I don't want to give up on this. When you look at the design on that link above, you can see that the part that touches the strings is a rubber roller skewered and glued to a metal rod. There is a little space on either side of the roller, where I could potentially add some more rubber. Another possibility would be to replace the roller entirely.
So, I guess my question is: how would you proceed? It seems like I would have to do my best to match the rubber with the same density of rubber that is on the roller now, but I don't know how to begin (I have determination but admit to iffy skills in the diy maker department).
Oh, and the song is a 7-string solo instrumental arrangement of Stereolab's blips, drips and strips. It has already taken me months to get this far!
That rubber roller looks an awful lot like something you'd find inside a computer printer. You might be able to find a scrap printer and cut a section down, it won't have the taper but maybe the taper isn't that critical. Or, if you can find an oversized roller you could mill it down to taper it like EKStickland suggests.
Idea 2- buy a second rolling capo, cut the rollers from both and splice them together somehow to make a wider one. I can't tell from the photo, but presumably there's a metal rod going though the center of the roller. Does the rubber roller also have a metal tube bonded to it which rolls over the rod? Or is the rubber roller bonded to just a single piece of solid rod which pokes out at both ends? How it's constructed will determine how it might be possible (or not) to splice two together.
Idea 3- A machinist could fabricate a custom roller out of delrin, brass, what have you. Easy peasy with a lathe. You could then rubberize the outside of it with plasti-dip. (Used to put the rubberized coatings on hand tool handles and such.) I'm not sure how well this coating would hold up long term, but I think it would work for a while.
posted by Larry David Syndrome at 4:23 AM on January 8, 2022
Idea 2- buy a second rolling capo, cut the rollers from both and splice them together somehow to make a wider one. I can't tell from the photo, but presumably there's a metal rod going though the center of the roller. Does the rubber roller also have a metal tube bonded to it which rolls over the rod? Or is the rubber roller bonded to just a single piece of solid rod which pokes out at both ends? How it's constructed will determine how it might be possible (or not) to splice two together.
Idea 3- A machinist could fabricate a custom roller out of delrin, brass, what have you. Easy peasy with a lathe. You could then rubberize the outside of it with plasti-dip. (Used to put the rubberized coatings on hand tool handles and such.) I'm not sure how well this coating would hold up long term, but I think it would work for a while.
posted by Larry David Syndrome at 4:23 AM on January 8, 2022
Diy might not be too hard. Try looking around the McMaster Carr website.
Some hard rubber washers, threaded rod, metal washers for the ends, nuts or wingnuts to squeeze your stack of washers together, and then reuse the original springs and rear part? McMaster will also have springs with hooks on the ends that you could slip over the threaded rod.
If that doesn't roll smoothly enough, you might look into what stuff rubber hoses or conveyor rollers they may have that you could cut down.
Did you ask if they would just make a custom version for you? Should be trivial if they at least have enough equipment to make prototypes at their facility.
posted by jellywerker at 7:36 AM on January 8, 2022 [1 favorite]
Some hard rubber washers, threaded rod, metal washers for the ends, nuts or wingnuts to squeeze your stack of washers together, and then reuse the original springs and rear part? McMaster will also have springs with hooks on the ends that you could slip over the threaded rod.
If that doesn't roll smoothly enough, you might look into what stuff rubber hoses or conveyor rollers they may have that you could cut down.
Did you ask if they would just make a custom version for you? Should be trivial if they at least have enough equipment to make prototypes at their facility.
posted by jellywerker at 7:36 AM on January 8, 2022 [1 favorite]
is a rubber roller skewered and glued to a metal rod
Is it glued? It might just be held in place because the hole in the roller just fits tightly on the rod. They move too fast in the various videos, I can't tell if the roller is rolling when they change position or if it's just sliding over the strings.
Looking at the demo videos, I'm thinking 2 things; 1) I've got doubts about whether adding a washer-type thing to an end would work, I think you need a continuous piece of tubing, because the washer could rotate/move separately from the main roller and go out of alignment and 2) it looks like there is very little space for a larger roller - the metal end pieces are thicker than the rod that passes through the roller and from what I can tell those thicker pieces of metal are pressed right up against the ends of the rubber. Might take a few tries to cut a piece exactly the right size.
jellywerker beat me to it, I would definitely poke around McMaster-Carr for rubber tubing to replace the roller.
I suspect whether the curvature of the roller is important depends on the fretboard radius of your guitar. 7-string suggests an Ibanez or something fairly modern with a flatter radius (like 12" or 14"), so you might be OK with a flatter piece of tubing.
posted by soundguy99 at 7:49 AM on January 8, 2022
Is it glued? It might just be held in place because the hole in the roller just fits tightly on the rod. They move too fast in the various videos, I can't tell if the roller is rolling when they change position or if it's just sliding over the strings.
Looking at the demo videos, I'm thinking 2 things; 1) I've got doubts about whether adding a washer-type thing to an end would work, I think you need a continuous piece of tubing, because the washer could rotate/move separately from the main roller and go out of alignment and 2) it looks like there is very little space for a larger roller - the metal end pieces are thicker than the rod that passes through the roller and from what I can tell those thicker pieces of metal are pressed right up against the ends of the rubber. Might take a few tries to cut a piece exactly the right size.
jellywerker beat me to it, I would definitely poke around McMaster-Carr for rubber tubing to replace the roller.
I suspect whether the curvature of the roller is important depends on the fretboard radius of your guitar. 7-string suggests an Ibanez or something fairly modern with a flatter radius (like 12" or 14"), so you might be OK with a flatter piece of tubing.
posted by soundguy99 at 7:49 AM on January 8, 2022
I'm gonna guess the company is buying rubber tubing in bulk and cutting it down to size. Perhaps you can ask them to sell you a slightly longer piece to replace yours with?
If you do add washers after all, just make sure you glue them to the main roller so they all rotate together.
posted by ananci at 8:30 AM on January 8, 2022
If you do add washers after all, just make sure you glue them to the main roller so they all rotate together.
posted by ananci at 8:30 AM on January 8, 2022
Response by poster: Thanks, everyone, for giving me lots of promising leads. I just realized that the university where I work has a maker space with a coordinator who helps people with projects. I'm going to bring this link to him and work on these possibilities.
posted by umbú at 8:46 AM on January 8, 2022
posted by umbú at 8:46 AM on January 8, 2022
Take the capo to an auto parts store, tell them what you're trying to do. I would bet that half the dudes working at Auto Zone are also guitar players (this is a stereotype, I know, but I have known many Auto Zone employees and they all have a BC Rich guitar at home) and you might get one of them who thinks this is a cool project. They might be able to find a rubber hose that fits the metal rod.
It does look like it's slightly narrower in the middle, perhaps it will still work on your guitar, or maybe you could sand it down to shape somehow.
posted by bondcliff at 11:31 AM on January 8, 2022
It does look like it's slightly narrower in the middle, perhaps it will still work on your guitar, or maybe you could sand it down to shape somehow.
posted by bondcliff at 11:31 AM on January 8, 2022
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It looks like the original capo is flared larger on the ends, presumably to accommodate a variety of fretboard radii; depending on how flat (or not) your fretboard is, you might want to go slightly larger with the washer on the end, too.
posted by EKStickland at 9:54 PM on January 7, 2022 [1 favorite]