Cepheid 5: Ripthorn Builds a Bass

Discussion in 'Luthier's Corner' started by Ripthorn, Oct 20, 2019.

  1. Ripthorn


    Jul 15, 2008
    So with the epoxy pretty well set, I pulled the clamps off and it seems to be holding nicely. I routed the edges flush with the back of the body, sanded the aluminum with 120 (what I had on the sander), and cleaned it up with acetone.


    This guy is ready for a top, so I mixed up about 2 oz. of epoxy, spread it on the aluminum, and then filled in inside the aluminum, with the thickest portions being in the upper horn and the lower bout of the body. I started clamping at the end strap button and lower bout along with the upper horn, forcing any excess epoxy out the vent channel and hole. I flipped it upside down so that the vent hole would stay free and so that epoxy wouldn't run down the nice sides of the body back. I used just a couple clamps:


    While that did its thing, I thinned down the headstock. I have just enough space for the headstock and fretboard as is, so I had to thin it by taking some off the back. Looks like I get to figure out how to do an angled volute! Or I can just do no volute. Either way, the compound scarf joint came out really nice and clean.


    The neck then got dealt with on the front side. I'm doing a 24" truss rod and about 26" long, 1/8" thick, 5/16" wide carbon fiber stiffeners. This is just mocked up:


    I also ran the face of the headstock over the jointer a bit. I drum sanded some of the birdseye maple cutoff so that I can do a matching headstock to the body, with an aluminum veneer between the bocote and birsdeye. It will also cover the angled ends of the carbon fiber.

    Tomorrow I hope to trim the top flush, get the carbon fiber epoxied in, and make a template for my headstock so that I can cut and glue some wings on it.
  2. Dark Horse

    Dark Horse Supporting Member

    Jul 31, 2008
    Austin, TX
    This project is looking great !

    that compound scarf joint ... mind blown !
  3. This is looking incredible I cant wait to see how the finished project will look
    Beej and Reedt2000 like this.
  4. Ripthorn


    Jul 15, 2008
    Happy Easter to everyone! Yesterday and Friday were fairly productive. I radiused the fretboard. I normally use a jig where the board swings and the router routes the radius with a straight bit, but this board is too long (I normally do guitars). Well, I have had a radius router bit kicking around for a couple months waiting to get tried out, so I did. I roughed out the radius pretty well, no tearout and no real issues:


    I also pulled the body out of clamps and trimmed the top. I also had to glue on headstock wings prior to the headplate and I rough cut the pieces for the bridges. So here we have what will become the guitar and bridge, I just need to remove all the material that doesn't make a pretty bass and awesome bridge:


    I will get the headplate glued on first, then glue on the fretboard, trim up the neck, route the headstock. Then I need to route the neck pocket, but I want at to have bridges done first so that I can make sure that they will be placed correctly on the body. That means the woodworking will slow while I do the machining of the bridges. I have the process all laid out along with some CNC code, I just need to spend the time making it. It's getting fun!
    wraub, Ethereal Thorn, Beej and 7 others like this.
  5. Ripthorn


    Jul 15, 2008
    I got the headplate epoxied on to the neck blank:


    Then, I set to work on the Dingwall-style bass bridges. I have 7 blanks because inevitably I will screw up at least one, possibly two. This is slow going, as I am manually checking a bunch of stuff and making sure that all the design works the way it should. Basically the procedure is to remove all the stuff that isn't the bridge and don't remove anything that is. As you might be able to spot, there is one piece where I did remove some of what will be the bridge. Thus the 7 starting blanks :) I just about have them all ready for shaping. This represents probably 5 hours on the mill, but again, lots of measuring and on the fly tweaking. Pretty happy with where things are at so far.


    Next up is getting the headstock cut and routed, glue on the fretboard, and finish off the bridge pieces.
  6. Ripthorn


    Jul 15, 2008
    So a few things have happened. First, the birdseye maple started delaminating from the aluminum in two spots on the treble side of the body. I flooded the areas with CA and clamped and it has been holding for a couple days now, so I'll just chalk it up to a 50 degree temperature swing over the course of two days. Like I said before, this could be a disaster.

    I pulled the clamps off the headstock and cut and routed the headstock to shape. No picture, as I was in a hurry to move on to the bridges.

    For the bridges, I got all the structural machining done. I decided to scrap the idea of mounting the string ball ends on a pin and instead changed to just having a feature for capturing the ball end. Then I tapped all the holes. After that, it was time for shaping. For shaping the arc on the front and back of the saddle, I made up a little swing jig to work with my ROSS to put the 2.25" radius on the ends:


    To shape the top, I made up another scrap wood swing jig. This time it's a 7.5 inch radius:


    I used up an entire 80 grit belt on the 6 bridges, but that's ok by me. I roughed the arc on my metal bandsaw and then used the swing jig. Here's what a bridge looks like fresh off of it:


    Then I switched out for a fine belt. After that, it's wetsanding at 400 grit, then maroon and gray scotch brite. Here is the first one done:


    Today I hope to finish off the rest and then get the fretboard glued on. We'll see how it pans out.
    5tring, rwkeating, Beej and 4 others like this.
  7. You know the competition is fierce when somebody's making their own aluminum bridges :wideyed:
    EddiePlaysBass, GMC, Beej and 2 others like this.
  8. Ripthorn


    Jul 15, 2008
    Eh, I've done this many times. I love designing my own stuff: bodies, knobs, bridges, I've even designed and machined my own headless tuners for a multiscale. I don't like doing the same thing twice, for the most part. I don't see this as a competition, but as an opportunity to participate in a huge outpouring of creativity.
    EddiePlaysBass, dmarino, Beej and 3 others like this.
  9. That's a good way to look at it :) I would make my own bridges too if I had the equipment! Mind you I could just design something in CAD and have it machined, but that gets awful expensive pretty quickly.
    TerribleTim68 likes this.
  10. Ripthorn


    Jul 15, 2008
    Try buying the machinery! Luckily, I've made a large number of items on mine and it has totally been worth it to me.
  11. I've promised myself a small mill and lathe in the future! It might have to wait until I move into a bigger shop, but if you have any recommendations...

  12. Those bridges look good. I like the jig for the sander. I’ve done similar stuff with wood but, for whatever reason, I might not have thought of doing that with metal. Post some detail pics of the bridges when they’re done.
  13. I think I'll just draw it and then lean on my brother-in-law who works at a massive steel fab shop. They have all the equipment you could ever dream of. :cool:
  14. Dark Horse

    Dark Horse Supporting Member

    Jul 31, 2008
    Austin, TX

    Amen !
  15. Ripthorn


    Jul 15, 2008
    Grizzly g0704 or precision matthews pm25 for a mill and grizzly g0602 for a lathe. I have a 7x14 lathe and would like to upgrade.
    BioWeapon likes this.
  16. Ripthorn


    Jul 15, 2008
    Well, I got the fretboard glued on yesterday:


    I also spent about an hour and a half doing the final finishing on the bridges. A little matte clear to seal them and to give them that really finished look:



    I was originally planning to have aluminum base plates for each that they mounted to and that would be recessed in the body. But now I am thinking that I will probably just mount these direction to the body. I need to figure out what the right placement will look like for intonation. I have no idea what a 5 string bass intonation looks like, so if you have some insight, like how far beyond nominal string length bass strings need for proper intonation, I would love to hear it!
  17. Don't you just set the bridge with the saddle somewhat centered at the given scale length and let the adjustment account for intonation? Or are you saying you actually build some intonation into the bridge placement?
  18. Ripthorn


    Jul 15, 2008
    Correct, I am thinking of building some intonation into the placement. I just don't know what a low B needs, as this is my first 5 string and my first bass in over 10 years.
  19. ctmullins

    ctmullins Dominated Gold Supporting Member

    Apr 18, 2008
    MS Gulf Coast
    I'm highly opinionated and extremely self-assured
    Not centered, no. Intonating typically (always?) results in moving the saddle back, away from the nut, not forward. So you want most/all of your adjustment range towards the back.

    Because bass string thicknesses vary in a gradual and linear fashion, intonation does too. Add the thickness of your G string to your scale length, and start with the G saddle at that point. The thicker strings will be progressively farther than that, ending up in a basic slanted line.
  20. So I was always told that the intonation is the scale length plus the amount of thickness of the given string subtracted from the thickness of the next higher string. So in the case of the low B it would be the thickness of the B string minus the thickness of the E string. Which is why every set of strings intonates differently, because in reality they are never exactly the thickness the package says. But I would think that math could get you in the ballpark, right?

    Unless I'm just way off here. Bueller? Bueller? Bueller?