1. Please take 30 seconds to register your free account to remove most ads, post topics, make friends, earn reward points at our store, and more!  

Help Needed: Converting a sub short to a short scale

Discussion in 'Luthier's Corner' started by ejaggers, Jul 31, 2020.


  1. ejaggers

    ejaggers

    Aug 18, 2009
    Fort Worth, tx
    I have a 60’s Kingston sub short scale (25”) bass that I bought for reasons unknown.
    I wasn’t even drinking that day, anyway…

    My luthier said the neck is shot ( can’t remember if it’s a truss rod issue),
    but I’d like to convert it to a 30”.
    The current neck is 18” x 2” at the heel, the 2” is my first problem.

    My second problem is, it’s old 60’s junk, and SS necks are expensive, and hard to find.
    I’m not wanting to throw a lot of money in this project,
    but I’d like your opinion on what it would take to make this happen.
    Kingston.jpg
    057912
     
  2. dwizum

    dwizum

    Dec 21, 2018
    At a current scale of 25" you're basically talking about converting a guitar sized instrument into a bass.

    Scale length conversions can be done without body modifications if you account for the distance between the bridge and neck pocket, and then work backwards from your new scale length to determine what fret position would end up at the end of the neck pocket. Then you make or find a neck with the "right" fret at the end of the fretboard.

    Probably easier to walk through an example. I see your current neck has 21 frets. Using the 21st fret position for a 25" scale (roughly 17.5") we can subtract that from the scale length to determine how far the bridge is from the neck pocket. This gives us a distance of 7.5" between the bridge and that 21st fret (you can measure this to confirm - you'll probably get a number a little higher than that due to compensation for intonation). Working backwards, for your desired 30" scale, 7.5" from the bridge would be 17.5" from the nut, which would be the position of the 24th fret. So, the "easiest" way to get a 30" scale on that bass, in terms of needing no modifications to the body, would be to have a custom neck made to fit that heel pocket, with 24 frets (such that the 24th fret was right where the current 21st fret is). Or if you hit the jackpot and happen to find a 30" scale neck that fits the pocket with 24 frets, you could use that.

    Of course, making the neck so much longer like this, on a bass with a short upper horn, may cause some pretty bad neck dive.

    Another alternative would be to modify the neck pocket to fit an existing 30" neck. But, unless you also want to move the bridge, you may have trouble finding a neck that's long enough. Many bolt on necks end at the 21st or 22nd fret, so they basically aren't "long" enough for your short body. You can't just slap a 22 fret neck into the existing pocket (even if it fits) because the bridge will be in the wrong spot relative to the scale length, and the bass won't play in tune. For an example, let's say you find a 22 fret neck in 30" scale length that fits the pocket (or you modify the pocket to fit it). That 22nd fret will be 7.5" from the current bridge. But for a 30" scale, the 22nd fret needs to be 8.42" from the bridge. So, you'd have to move the bridge back almost an inch (it does look like there's room on the body for that).

    Might be worth asking your luthier what their opinion is since they've seen the bass in-hand...
     
    wraub and ejaggers like this.
  3. If it is 25” scale you might be able to get a guitar neck with a blank headstock and drill it for bass tuners and make a new nut. Follow @dwizum directions above and make sure the bridge lines up with where it should be. You’ll probably find 25.5” scale Fender necks but they might line up.
     
    eddododo and ejaggers like this.
  4. dwizum

    dwizum

    Dec 21, 2018
    I bet a Fender-style guitar neck would actually be pretty close. 25.5" scale length and the neck ends in a similar spot as the OP's neck (basically just past the 21st fret). Probably close enough to get it to work, depending on how much saddle adjustment room this bridge has. Of course, Fender heels are 2 3/16" wide by 3" long - sounds like your pocket is too narrow at only 2" (which you could fix by routing the pocket bigger, or trimming the neck heel but leaving the fretboard intact).

    Warmoth sells a baritone conversion neck designed for use in a Fender neck pocket, with the standard bridge placement, to get a 28.5" scale length. Might be tough to find strings that fit, but it could be a good option.
     
  5. I couldn’t remember the Fender heel width but I have rebated neck heels before. If you’re careful it can look fine.
     
    ejaggers and dwizum like this.
  6. rudy4444

    rudy4444

    Mar 13, 2012
    Central Illinois
    If this were mine I'd make a new 30" scale neck, making the new one wider at the heel and lengthening the neck pocket by whatever the body would accommodate. Making the pocket bigger is a lot easier than making one smaller... :)

    The "cost" is mostly labor, as you can re-use the tuners. Neck wood, fret board, frets, and a few position dots would be south of $50 in parts.

    If you need fret layout for a 30" neck you can use the layout on the CAD drawing I provided in my " 30" scale compact fretless semi-acoustic" build topic.
     
    ejaggers likes this.
  7. ejaggers

    ejaggers

    Aug 18, 2009
    Fort Worth, tx
    Rudy,
    What would you charge for making a neck, and converting this to a 30"?
    I'm just curious because actually I'm not sure this is worth the effort.

    I can't do the conversion myself, but I can mod it.
    It could use re-wiring, but I think the PUP is okay.

    057912
     
    Last edited: Aug 1, 2020
  8. ejaggers

    ejaggers

    Aug 18, 2009
    Fort Worth, tx
    I was thinking getting the cheapest 30" neck, widening the pocket, and moving the bridge.

    This is actually old Japanese junk, but the body style is so cool to me.
    But it's probably unrealistic for me to fix this up, the lipstick, and wig on a pig scenario.

    057912
     
  9. ejaggers

    ejaggers

    Aug 18, 2009
    Fort Worth, tx
    Matt,
    Are you saying a guitar neck would work if I wanted to stay with the same scale?


    @dwizum, @rudy4444,
    What would it take to replace the TR on this neck?

    057912
     

  10. It might. If you do like @dwizum said and figure out where the last fret on a Fender style neck will sit and see if it lines up with where the bridge is. Alternatively, you might have to move the bridge. Either way, the neck route in the body or the neck heel will probably require some adjustment.
     
    ejaggers likes this.
  11. dwizum

    dwizum

    Dec 21, 2018
    Truss rod replacements usually involve removing the fretboard, which can't always be done non-destructively. It's probably a good several hours of work. In terms of rough estimates it's probably not much different than the level of effort it would take to modify a typical modern neck and/or the body to get them working together - since you seem budget-conscious I'm not really sure it would make sense to pay someone to do either...

    Can you clarify exactly what is wrong with the current neck (or truss rod)? If all you're trying to do is get a cheap and functional bass, there may be compromise/workarounds to get this playable.
     
    ejaggers likes this.
  12. Beej

    Beej

    Feb 10, 2007
    Vancouver Island
    To help vision this with a 30" neck: if you mount a 30" scale neck and keep the bridge at the same location, the new neck will have a 12th fret at roughly where the 9th fret currently is on the 25" scale neck. The nut will be 5" further away (obviously). This is perfectly doable with a new neck, like @rudy4444 mentions above. Another thing to think about is the pickup will effectively be in a new location compared to the 25" scale - closer to the bridge (relatively speaking).

    Have you got any woodworking skills or access to tools? Making a neck always seems daunting, but it's pretty straightforward to make a neck like the one on that bass, if you have access to tools and a little workshop. :thumbsup:
     
    ejaggers likes this.
  13. eddododo

    eddododo Supporting Member

    Apr 7, 2010
    That’s a really cool bass...


    I can’t be that useful compared to the people chiming in, but I DO know that the Ibanez mikro and short scale stuff is ~28.5” really slick playable necks, and they can be found for as little as $99 to $150 used!

    edit: the Ibanez 34 scale parts I have sitting around are ~2 3/8 at the pocket-
    I’m ALMOST certain that the pocket for the short scale may be the same- I have a few different related pieces and they use a LOT of interchangeable parts, templates, and dimensions between the Mikro, GSR (34”) and the Mikro 5..

    Any guitar center has 57+ of the Ibanez Mikro 4’s to go measure, otherwise you could get crazy and use a Mikro 5 neck and make this thing something new entirely
     
    Last edited: Aug 1, 2020
    ejaggers likes this.
  14. eddododo

    eddododo Supporting Member

    Apr 7, 2010
    And if for whatever reason you end up deciding it’s not worth the time and you want it gone, go ahead and send me a message :)
     
    ejaggers likes this.
  15. dwizum

    dwizum

    Dec 21, 2018
    Mikro necks are a great idea. Google says the pocket is 2.2". Close enough to make for an easy modification. I'd wanna check the bridge position too, but I bet you could buy a cheap mikro, take the neck, and sell the rest to recoup some of your cost...
     
    ejaggers likes this.
  16. rudy4444

    rudy4444

    Mar 13, 2012
    Central Illinois
    This is a $200 job IF I did bass work beyond what I do for myself, which I don't. The banjo stuff keeps me as busy as I want to be. :)

    Finding a used short scale to use the neck from might be an option depending on your local used market. I recently bought a Mikro that was less than a year old for $50 on Craigslist, but I bought it to use mostly as it came, other than doing the Master volume / J blend / tone control mod.

    Checking Amazon I see a new "small scale" bass for less than $100 that MIGHT work. Pulling the parts and ebay-ing them separately would get you the neck for free if you wanted to go through the effort.
     
    ejaggers and eddododo like this.
  17. ejaggers

    ejaggers

    Aug 18, 2009
    Fort Worth, tx
    It’s a semi-good option to restore it to a 25”, but sub’s feel weird to me.
    I would restore it as a last resort, but would prefer 30”.


    My luthier told me awhile back, but I don't remember anything after,
    “This neck is shot, and it’s not worth fixing”.
    At that point this bass just became wall art to me.

    However, the more I look at it, the more I see it as a possible project,
    but I’m having a hard time justifying it since I’m starting out with junk.

    I don’t have woodworking tools, but I would try making one to see if I could.
    I’m very anal-retentive and a half-ass neck would drive me nuts.


    Yeah, I thought about a Mikro neck, but I haven’t seen any used on my CL.
    I’ve also never played a Mikro but I am a short scale guy.
    BTW, short scale and 5er makes my head spin!!!

    On the serious side, getting rid of it is probably the best idea.

    Because I’ll walk away from it for a while, but always come back to, “what if I can do this”, scenario.
    I almost threw it away in one of those scenarios.

    What would you do with it?

    I’ve actually been looking for one but haven’t seen any under $180.
    Plus, what it would cost to have someone who knows what they’re doing to make the neck work.


    Wish I could find $50 deals on my CL.
    The only ones I find are generally P basses,

    And I don’t need another one of those.
    I haven't found any SS necks, except the ones where you have to shape the headstock yourself, and I’m not a woodworker.

    057912
     
  18. eddododo

    eddododo Supporting Member

    Apr 7, 2010
    I’d either convert a Mikro neck with a reshaped headstock, or, depending on how my current project turns out, I’d build a scratch neck for it.
     
    ejaggers likes this.
  19. ejaggers

    ejaggers

    Aug 18, 2009
    Fort Worth, tx
    Then getting it to you has become one of my scenarios.
    I'd like to see this little sucker pimped out even if I can't (or won't).

    And as long as I have it, it's going to bug me,
    because I've always considered wall art, pictures.

    My wife bought hangers to put it on my grandsons wall,
    but if she hasn't done it by now, I don't thin she will.
    Which is another failed scenario.....057912

    BTW, don't you just hate people that over use the word "Scenario"?
     
    eddododo likes this.
  20. dwizum

    dwizum

    Dec 21, 2018
    Ultimately, a scratch neck seems like the best choice, you could totally avoid all the other fiddling around...
     

Share This Page

  1. This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
    By continuing to use this site, you are consenting to our use of cookies.