4 to 5 string conversion idea... Thoughts?

Discussion in 'Luthier's Corner [DB]' started by agfrag, Jun 1, 2021.


  1. agfrag

    agfrag Supporting Member

    Feb 24, 2006
    Novi, Mi
    I am pondering doing a conversion on my plywood Double Bass from 4 to 5 strings, by adding a high C string. I am thinking of adding a tuner to the tailpiece of all places, and then configuring an "anchor" for the ball end of the string, somewhere in the scroll area. What drives me to think this may be possible are a couple of unique features of this particular bass:

    1. The fingerboard is quite wide. The distance from the E string to the fingerboard edge at the end of the fingerboard is 7/8 of an inch, and the distance from the G string to the edge of the fingerboard at the end of the fingerboard is about 3/4 of an inch.

    2. The nut is wide as well, it is actually wider than my 5 string 3/4 size EUB's nut, and I am quite comfortable with that nut.

    3. This is the strange part... The soundpost is supported by a strip of wood on the back of the bass which goes across the entire width of the back. I've not seen this before on any of my previous basses, nor could I find any illustrations of a similar post support on the internet.

    4. The end block is kinda big as well, but not sure that matters.


    I would have to replace the bridge of course, and make a custom tailpiece (not a problem, I have too many woodworking and luthier tools), but I am led to think that due to the massive soundpost support, and the "brickhouse" nature of the rest of the build, I may be able to add the stress of the C string, without too much worry.

    I didn't pay a lot of money for this bass, but for some strange reason, it is quite the best sounding bass I have owned of the five I have owned, and of the thousands of dollars I have spent on the previous basses!

    I can't find any record of any other attempts to do this as a guide, so I would be glad to hear any comments you might have...
     
  2. LouisF

    LouisF Supporting Member

    Apr 21, 2003
    Los Angeles, CA


     
  3. agfrag

    agfrag Supporting Member

    Feb 24, 2006
    Novi, Mi
    Thanks for your response, LouisF.
    I did indeed check out this series of videos and determined that none of the content apply in my case due to the fact that there is no room in my pegbox for another tuner (which is a shame as I have an extra set of individual tuners in my possession!).
     
  4. LouisF

    LouisF Supporting Member

    Apr 21, 2003
    Los Angeles, CA
    It's a project I've thought about a few times myself. Good luck.
     
  5. Steven Ayres

    Steven Ayres Supporting Member

    Mar 11, 2007
    Northern Arizona
    Kay experimented with the transverse back brace in its first year of bass production, then reduced it to a 2-3" reinforcement disc on the back for the post.

    Here's the thing: if you're happy with how the bass sounds with four strings, be aware that it will sound different with five, due to the additional pressure on the table.

    It occurs to me that one may be able to test this before taking on a conversion by tuning the strings sharp to simulate the additional pressure; I'm guessing someone here might know how to calculate that pitch change.
     
  6. five string combo.jpg Do you have a friend who is handy with a lathe and metal work? I had a removable 5th string set up for a Low C that is based on the "spool" being a sleeve rotating around the brass peg of the E string for support/strength. This is turned by its own small worm gear whose knob protrudes from the front of the pegbox. The worm gear is mounted on its own plate that is screwed to the inside face of the pegbox. If I hadn't sold the bass I could have better photos but you can see the neatness of the result. I don't think there is anything like this available commercially. Big advantage sare that it caters for a 4 string pegbox, leaves four small screw holes when removed and can interchange between 4 and 5 strings by changing the bridge (or having two lots of grooves) and nut. Food for thought?
     
  7. agfrag

    agfrag Supporting Member

    Feb 24, 2006
    Novi, Mi
    Curious... was it similar to this one by Martyn Bailey?
    I had looked at this but was hesitant due to what I imagine the cost might come to...

    3-5 string tuner 2.jpg
     
  8. This is the very professional upmarket version of what I described above but neither my Luthier, C.A. ("Harry") Vatiliotis nor myself have ever heard of Martyn Bailey. Is he English? The original idea may have come from an old bass player in the London Symphony Orchestra in the 60s who was quite inventive. I met him in London when on tour in 1974 and later bought a converted bass with a very crude version from my teacher, also an Englishman. Later I commissioned the bass pictured above from Harry and he built his own very similar arrangement to the above for me. He too is an extremely inventive man, one of the most intelligent I have ever met.

    The unit above looks really great but leaves me with one question. It appears to be a new build, including the fresh looking peg holes, so that the sleeve could be turned to neatly fit over the new brass peg. Is it possible to retro fit this unit to an existing old peg?

    I have just found the Martyn J. Bailey site. Yes, English and can be retrofitted with his help but a very good clean solution if you think your bass is worth it IMO. Cheers, DP
     
    Last edited: Jun 3, 2021
  9. agfrag

    agfrag Supporting Member

    Feb 24, 2006
    Novi, Mi
    I have emailed Mr. Bailey about his device, and hope to hear from him soon.
     
  10. eerbrev

    eerbrev

    Dec 6, 2009
    Ottawa, ON, CAN
    I think there's a relatively famous Prescott that had the 4th tuner on the tailpiece (it had originally been a three string).

    One other thing to consider (as a 5 string player myself) is to make sure the fingerboard is wide enough. I want to say that there was a bassist, Paul Warburton, who used to post on here many moons ago (I believe he's sadly passed away) whose 5 string had a fingerboard that was a bit wider than the neck itself - food for thought if you find the neck is too cramped.
     
  11. LouisF

    LouisF Supporting Member

    Apr 21, 2003
    Los Angeles, CA
  12. After my last post above I allowed my ancient brain to trawl through its archives. The old LSO bass player I met was Bob Norris who loaned his Hart bass to my colleague in an emergency while his fingerboard was re-glued on. I also went to my "glory box" of bass stuff and found the device that I tried to describe above. IMG_1006.JPG IMG_1007.JPG IMG_1008.JPG It is so simple and crude but it worked well. I replaced it later by re-using one of the original Fawcett extension machines that was , I think, the first in Australia when I bought it in 1970. This was after seeing one on John Gray's bass when he first came with Yehudi Menuhin's orchestra. His mechanical "fingers" were retracted by a forest of rubber bands. Fawcett was still working for the RAF and made his machines from scrounged bits and pieces . He very generously sent me detailed hand-written mounting instructions with photographs. His brother was an amateur bass player, I recall.

    Coming back to your original ideas, agfrag, I wondered about using two carefully spaced screws on the inside of the peg box cheek to slot the knob of the string into. To provide tension how about using a stainless steel turnbuckle such as used for tensioning yacht rigging. This could be quite small and give you the range of movement to tighten the string. The fifth string could use the existing tail piece by drilling a hole for the D string to centre the forces.

    Cheers, everyone, and keep safe (get vaccinated !!)

    DP
     
    strigidae, marcox and Tom Lane like this.
  13. GretschWretch

    GretschWretch Supporting Member

    Dec 27, 2013
    East Central Alabama
    The device in the pic looks like something that would be used to adjust the elevation on a WWI field piece.
     
  14. bassmanbrent

    bassmanbrent Supporting Member

    Apr 5, 2011
    Vancouver, BC
    Paul Warburton doesn't visit this site anymore, but he's still very much alive and quite active on FB.
     
    eerbrev and Eric Hochberg like this.
  15. eerbrev

    eerbrev

    Dec 6, 2009
    Ottawa, ON, CAN
    Glad to hear it! I don't know why I thought he was dead.
     
  16. Brent Nussey

    Brent Nussey

    Jun 27, 2001
    Tokyo, Japan
    Eugene Wright's Prescott

    2004_NYR_01369_0018_000(075258).jpg
     
  17. eerbrev

    eerbrev

    Dec 6, 2009
    Ottawa, ON, CAN
    THANK YOU.

    I've been low key looking for this since I mentioned it!
     
  18. agfrag

    agfrag Supporting Member

    Feb 24, 2006
    Novi, Mi
    Wow, just wow on the patented 1915 tuners on Paul's bass... Took me a second to realize that it has a one piece back-plate. It should get some kind of Steam Punk award.

    Joseph Bohmann1915 tuners.jpg
     
    Leigh Semmens likes this.
  19. agfrag

    agfrag Supporting Member

    Feb 24, 2006
    Novi, Mi
    Before I saw the 1915 tuners, I threw together a "reversed peg" tuner concept idea in Sketchup (after I saw the 1915 tuners, I think I'm ashamed of everything I've ever designed in my whole life!). It would sit between the E and A string tuners on the inside of the pegbox, there's just enough room if I file a notch in the tuner back plate. It would require me to drill holes in the pegbox walls, but so would adding a fifth tuner anyway...

    5th string tuner concept.JPG
     
  20. Have you considered repurposing an existing set of gears that are made for each other? I have seen 1/4 Plate machines where the large cog is attached to the peg by a screw. If you took the cog off the peg and machined a hole that fitted the existing peg on your bass it could be a good start for your design. The 1/4 plate and worm gear could be mounted on the inside of the pegbox. All that would be needed is a spool brazed or soldered to the large gear and rotating around your peg to wind the string over? Do you have a friend with a lathe?
     
  21. Primary

    Primary TB Assistant

    Here are some related products that TB members are talking about. Clicking on a product will take you to TB’s partner, Primary, where you can find links to TB discussions about these products.

     
    Jul 30, 2021

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