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de afwerking mk4-4++ - blablas has that building itch again

Discussion in 'Luthier's Corner' started by blablas, Jul 12, 2014.


  1. I'm beginning on a new build.... and build thread.

    The plan is to make a (left handed) 12 string (4 + 2 octave strings per string), it will once again be based on my mk4 single cut body design.

    Most of the CAD-work is already done, the tuner layout, the placement of the bridge and the fret positions.
    [​IMG]

    I've also been working on the headstock shape.
    [​IMG]
    Due to the huge amount of tuners I'm limited to working with straight lines, if I try a curve somewhere I run into position problems with them.
    I'm really happy with the tuner layout so I'm afraid I'll have to live with these straight lines.

    The advantage of these straight edges is that the fabrication of the headstock will be a lot easier. :)


    The details I'm pretty sure of:
    - 12 strings, 4 + 2 octave strings per string.
    - mk4 body design.
    - Bolt-on neck.
    - 35 inch scale.
    - 24 frets, brass nut.
    - Two dual action trussrods.
    - Schaller 3D-8 bridge (which will need some modifications to be used for twelve strings, and while I'm working on it some other refinements as well).
    - 4 Warwick bass tuners en 8 Boston guitar tuners.

    Things I need think about in more detail:
    - Pickups (two, probably dual coils).
    - Electronics (active, but which one).
    - Wood: body, top & back, neck & fingerboard.

    For the top and back I will use one of these two sets:
    Rosewood:
    [​IMG] [​IMG]
    the first one will be the top.

    Poplar burl:
    [​IMG] [​IMG]
    I'm net yet sure which of these two will be the top.
     
  2. pilotjones

    pilotjones Supporting Member

    Nov 8, 2001
    US-NY-NYC
    That rosewood sure is pretty. Would it darken up with a finish? or would it be left unfinished maybe?


    I was thinking about that headstock. I thought there was some possibility of making some curvature in there, without touching your tuner layout.

    I tried making a Tele style lefty, but it didn't work with the tuners. Something inspired by a normal righty one cold be like these,
    [​IMG]

    [​IMG]
    or, if you're willing to extend the overall length somewhat, it could be done with a larger, fuller top bulb.

    Reversed for your lefty, you get reverse-Tele types.
    [​IMG]

    [​IMG]

    The other possibility is to go like most of your other "blablas standard" headstocks--slight concave curves on both sides. There's enough room to make it work.
    [​IMG]
    And IMO it's so much more elegant than the straight-hacked sides.
     
  3. Probably, but if I'm using this one I will oil it anyway.



    Those Tele designs you did don't work for me, I prefer my headstocks more symmetrical.
    I like the last one you did, when I tried this sort of shaping this afternoon I couldn't get it to work, I'll give it another go tomorrow. :thumbsup:
     
  4. pilotjones

    pilotjones Supporting Member

    Nov 8, 2001
    US-NY-NYC
    Here's the sketch with the original lines still in, so you can see where the relative changes are.
    [​IMG]
     
  5. Dadagoboi

    Dadagoboi CATALDO BASSES Supporting Member Commercial User

    Jul 1, 2005
    Florida Swamp
    CataldoBasses: Designer/Builder ThunderBuckerPickups:Consultant
    IMO 12ers are easier to tune if you use 2 different tuners for the octaves. Easier to figure out which one you're tuning without looking. Schaller makes two quality styles of guitar tuners. These are cheapo Chinese.
    [​IMG]

    It will be interesting to see your mods for the Schaller bridge. It works fine for me with the slots in the right place.
    http://www.talkbass.com/threads/12-string.1078138/
     
  6. Your build gave me the idea that this was exactly the bridge I was looking for. :)
    [​IMG]
    The main mod I want to do is see if I can give these ball ends a nicer fit by slotting the holes they go through, factory standard it's just a round hole I assume?
    I'm also going to ad at least two more screw holes for mounting the bridge to the body, for me as a engineer three just feels too risky when twelve strings are pulling on the bridge.
     
  7. Dadagoboi

    Dadagoboi CATALDO BASSES Supporting Member Commercial User

    Jul 1, 2005
    Florida Swamp
    CataldoBasses: Designer/Builder ThunderBuckerPickups:Consultant
    On Top Petersen's aluminum 12 the holes are slightly modded. I didn't see the need since everything works and there's not a lot of extra metal in that area. I'll also be using guitar strings for the high Es as well as the high Gs in the future. What I did have to do was relieve the A string saddle carrier where there was slight interference with one of the high As that caused buzzing. LH setup might cause a similar problem on different strings.

    3 screws are perfectly adequate to hold in pine, let alone alder. So no reason to add more IMO. It's possible you might need more in softer wood, there are also holes under the A and D saddles.
    I don't like to overdo things, spent too much time around structural engineers in my youth.
     
  8. If there are two holes underneath the A and D saddles I don't need to make extra holes. :cool:

    These two extra holes are by the way not showing in the Schaller drawing of this bridge (found somewhere on the Internet, the only place where you can always find what you are looking for, even if it is wrong :D).
     
  9. Dadagoboi

    Dadagoboi CATALDO BASSES Supporting Member Commercial User

    Jul 1, 2005
    Florida Swamp
    CataldoBasses: Designer/Builder ThunderBuckerPickups:Consultant
    So much for 'German Precision'. I was going to use those extra holes but forgot about them after I realized they were unnecessary. Just remembered when I replied. Schaller doesn't supply screws for those, you will need flat heads instead of the oval heads fitted in the other holes.
     
  10. I've been doodling around some more with the concave shape and still can't get it to my liking, I come up roughly with the same shape you did, but I don't like the way the tip of the headstock comes out, it just gets too wide, I prefer a slim looking tip, for the time being I'm staying with the straight lines, maybe when I start shaping the headstock I'll give it another go but I don't keep up my hopes too high.
    The straight edges don't really bother me by the way, the headstock will already busy enough with all those tuners and strings running over it.
     
  11. Dadagoboi

    Dadagoboi CATALDO BASSES Supporting Member Commercial User

    Jul 1, 2005
    Florida Swamp
    CataldoBasses: Designer/Builder ThunderBuckerPickups:Consultant
    What is the total center to center tuner distance on each side of your headstock? Mine is 126mm, same as Hamer. If something works steal it, modify it and make it your own. That's a fundamental designer rule.
    [​IMG]

    Yours seems much greater. With a 35" scale, double dual action trussrods and extra length on your headstock, neck dive could be a major problem as well as reach to the far tuners.

    The parameters that are highest on my priority list are ergonomics, weight distribution and overall weight. A bass that is uncomfortable or too heavy to play while standing will seriously limit its functionality IMO.

    As I say, these are my engineering guidelines. I'm always curious as to what other builders consider of primary importance...besides tone of course.
     
  12. Center to center my distance is 170 mm, I don't like wriggle my fingers around objects when I'm tuning, this is the minimal distance I feel comfortable with.
    I hope I compensated the weight gained by this distance enough by making the shape of the headstock more compact.
    I also don't expect any real problem with reaching the far tuners, this headstock is roughly 1.5 cm longer than the the one of my previous build, the 35" seven string, and I can reach those without any problems.
    I don't know if neck dive is going to be a issue, but considering the fact I go with a single cut body design and the strap button is positioned just beyond the eleventh fret I don't expect a problem.


    Meanwhile, I've been working on the body design, I think it's almost there, I'm not yet sure if I'm fully satisfied with the lower horn shape, for now I'm letting sink in this design and see if I want to do a little more reshaping.
    [​IMG]
     
  13. Decided on the pickups and preamp I'm going to use and ordered them.
    - Pickups: Delano SBC 5 HE/S (Set) - Yes, a 5 string set, on the 4 string set they have the sensing area is too small for the width of my string layout.
    - Preamp: Noll TCM 3 PM - 3 band, parametric midrange.
     
  14. I'm going with the rosewood for the top and back due to the simple fact that the poplar burl is to small for this body design.
    No problem, the poplar burl will be use for a future mk5 build.

    The first parts arrived today.
    [​IMG]
    The rest of the parts I need are also ordered, once these and the wood for the back are in I can start making sawdust.
     
    Splods likes this.
  15. And today the top for the back arrived at my doorstep.
    [​IMG]


    Decided on the wood I'm going to use for the body, khaya mahogany core, three ply birch accent layer between the mahogany and rosewood and of course the rosewood top and back.

    Re-sawed the body core, straightened the edges of all the layers for gluing and very roughly sawed the body shape.
    [​IMG]

    Re-sawed the top for the headstock from a leftover piece of the top.
    [​IMG]
     
  16. [​IMG]
    Finally got the headstock shape right, I got a flash of inspiration after I took a better look at what I did with my 8 string headstock. :)
     
    Puavo likes this.
  17. [​IMG]
    Most of the ordered parts are in, the only things that are still missing are the bass tuners and strings.

    [​IMG]
    A forest of clamps, the body layers being glued up.
     
    Splods likes this.
  18. [​IMG]
    [​IMG]
    Body out of the clamps, ready to be sawed in shape.
     
  19. Looks great..! I'm sure this will be -another- amazing build from you :)

    Question: Do you use regular wood glue for the rosewood front/back? It looks that way from the pics... I'm asking because some say Rosewood is difficult to glue due to the high oil content and that epoxy is advised. Apparently it can un-glue itself after a few years with regular wood glue. But I don't know if this is exaggerated... I'm curious to hear your thoughts and experiences on this
     
  20. Titebond original wood glue, haven't had anything come loose yet.
    Luckily I didn't know this or else I might have been worried to use this glue. ;)

    As far as I am concerned I think this problem is rather exaggerated, it would be a problem for all manufacturers that use rosewood fingerboards.
    And rosewood is the most common wood used for fingerboards!