Fret- and Headless Neck-Through Multiscale 6-String (Walnut-burl, Mahogany, Bubinga)

Discussion in 'Luthier's Corner' started by couchsofa, Oct 13, 2014.


  1. jcanderson

    jcanderson

    Apr 13, 2013
    Los Altos, CA
    Agreed. There's a reason why these are mainly in high-tech areas, and it's probably to provide resources to engineers working on side-project prototypes who are hoping to someday capitalize on their ideas. I haven't yet found a reason, myself, to justify the expense.
     
  2. NextFab is something similar, here in Philadelphia.
     
  3. jcanderson

    jcanderson

    Apr 13, 2013
    Los Altos, CA
    ...and there's a TechShop in Pittsburg.

    Although I haven't found a use, myself, for joining Techshop, they do have quite a few classes for which one does not need to be a member. And some pretty cool tools, too, such as a CNC ShopBot. Looks like it might be able to fab a bass body from a slab of wood and a CAD file.
     
  4. Whoa, that's expensive! But if they offer professional guidance and a proper shop setup it might be justified. Nobody at our FabLab gets payed. It's all voluntary/honorary and I pay about 12$/month, it will be around 40$ once we move to a larger space and have proper woodworking setup.
    But we really don't want to charge much more, sharing knowledge and enabling everybody to take part is of the essence here. It's all much more in the spirit of the concept of hackerspaces and "the third room".
     
  5. A little bit on topic;)

    I've written and simulated some gcode for the CNC (emc2.4).

    This script creates a indentation in a wooden base to place the brass, takes care of positioning issues.

    Code:
    %
    
    (Creates a nice bed to place the workpiece)
    
    G21 (using mm)
    G40 (manual toolrad comp)
    
    (Operation config)
    #<z-safe> = 20 (safe height)
    #<z-feed> = 0.5 (depth feed steps)
    #<toolrad> = 4
    #<feedrate> = 200
    
    (Workpiece params)
    #<width> = 15
    #<length> = 93.8
    #<depth> = -2
    
    G00 X0 Y0 Z[#<z-safe>]
    
    
    (Corners)
    
        G00 X[#<width> * 0.5] Y[#<length> * 0.5]
        G01 Z[#<depth>] F[#<feedrate>]
        G00 Z[#<z-safe>]
    
        G00 X[#<width> * -0.5]
        G01 Z[#<depth>] F[#<feedrate>]
        G00 Z[#<z-safe>]
    
        G00 Y[#<length> * -0.5]
        G01 Z[#<depth>] F[#<feedrate>]
        G00 Z[#<z-safe>]
    
        G00 X[#<width> * 0.5]
        G01 Z[#<depth>] F[#<feedrate>]
        G00 Z[#<z-safe>]
       
    (Return to Origin)
    G00 X0 Y0 Z[#<z-safe>]
    
    (Square)
    
        G00 X[#<width> * 0.5 - #<toolrad>]
       
        G01 Z[#<depth>] F[#<feedrate>]
       
        G01 Y[#<length> * -0.5 + #<toolrad>] F[#<feedrate>]
    
        G01 X[#<width> * -0.5 + #<toolrad>] F[#<feedrate>]
       
        G01 Y[#<length> * 0.5 - #<toolrad>] F[#<feedrate>]
       
        G01 X[#<width> * 0.5 - #<toolrad>] F[#<feedrate>]
       
        G01 Y0 F[#<feedrate>]
    
        G00 Z[#<z-safe>]
       
    (Return to Origin)
    G00 X0 Y0 Z[#<z-safe>]
    
    %
    This one cuts the first pocket.

    Code:
    %
    
    (Creates a nice bed to place the workpiece)
    
    G21 (using mm)
    G40 (manual toolrad comp)
    
    (Operation config)
    #<z-safe> = 20 (safe height)
    #<z-feed> = 0.5 (depth feed steps)
    #<toolrad> = 4
    #<feedrate> = 200
    
    (Workpiece params)
    #<wp_length> = 93.8
    #<width> = 12
    #<length> = 40
    #<depth> = 8
    
    #<steps> = [#<depth> / #<z-feed>]
    
    G00 X0 Y0 Z[#<z-safe>]
    
    G00 Y[#<wp_length> * 0.5 - #<toolrad> - 8] X[#<width> * 0.5 - #<toolrad>]
    
    #<current_depth> = [#<depth>]
    
    O101 repeat [#<steps>]
    
        #<current_depth> = [#<current_depth> - #<z-feed>]
    
        G01 Z[#<current_depth>] F[#<feedrate>]
        G01 Y[#<wp_length> * 0.5 - #<toolrad> - #<length> - 8] F[#<feedrate>]
        G01 X[#<width> * -0.5 + #<toolrad>] F[#<feedrate>]
        G01 Y[#<wp_length> * 0.5 - #<toolrad> - 8] F[#<feedrate>]
        G01 X[#<width> * 0.5 - #<toolrad>] F[#<feedrate>]
    
    O101 endrepeat
    
    G00 Z[#<z-safe>]
    
    (Return to Origin)
    G00 X0 Y0 Z[#<z-safe>]
    %
    Had some problems getting the loop to work (emc2.4 won't run while statements) but it runs just fine with repeat statements and subroutines.
    Second pocket and beveling is next.
     
    GrumpiusMaximus likes this.
  6. BruceWane

    BruceWane

    Oct 31, 2002
    Houston, TX
    tx/rx labs is in Houston; and, like most things when comparing Austin and Houston, seems a bit more affordable.
     
  7. Wrote the code for the second pocket:

    Code:
    %
    
    (Creates a the second, open pocket)
    (flip workpiece with closed pocket facing down on the clamped side)
    
    G21 (using mm)
    G40 (manual toolrad comp)
    
    (Operation config)
    #<z-safe> = 20 (safe height)
    #<z-feed> = 0.5 (depth feed steps)
    #<toolrad> = 4
    #<feedrate> = 200
    
    (Workpiece params)
    #<wp_length> = 93.8
    #<width> = 12
    #<length> = 46.9
    #<depth> = 8
    
    #<steps> = [#<depth> / #<z-feed>]
    
    G00 X0 Y0 Z[#<z-safe>]
    
    G00 Y[#<wp_length> * 0.5 + #<toolrad>] X[#<width> * 0.5 - #<toolrad>]
    
    #<current_depth> = [#<depth>]
    
    O101 repeat [#<steps>]
    
        #<current_depth> = [#<current_depth> - #<z-feed>]
    
        G01 Z[#<current_depth>] F[#<feedrate>]
        G01 Y[#<wp_length> * 0.5 - #<toolrad> - #<length>] F[#<feedrate>]
        G01 X[#<width> * -0.5 + #<toolrad>] F[#<feedrate>]
        G01 Y[#<wp_length> * 0.5 + #<toolrad>] F[#<feedrate>]
        G01 X[#<width> * 0.5 - #<toolrad>] F[#<feedrate>]
    
    O101 endrepeat
    
    G00 Z[#<z-safe>]
    
    (Return to Origin)
    G00 X0 Y0 Z[#<z-safe>]
    %
    I did a test run on a piece of wood and adjusted some margins.
    Then I decided to try it out on the brass bar.

    tumblr_nf1ywzqK8v1twvu9io2_1280.png

    Messy, very messy :)

    tumblr_nf1ywzqK8v1twvu9io3_1280.png

    And the finished prototype:

    tumblr_nf1ywzqK8v1twvu9io1_1280.png

    Some of the process was captured on video:




    Now I only need to repeat that for the next 6 tuners (so I got one extra unit for further prototyping).
     
    Last edited: Nov 14, 2014
    GrumpiusMaximus likes this.
  8. Finished 6 units today; still need to add 2 bevels though.

    tumblr_nf5g4uU2OU1twvu9io2_1280.png
    tumblr_nf5g4uU2OU1twvu9io1_1280.png

    Code for the bevel on the back:
    Code:
    %
    
    (creates a bevel on the back side)
    (clamp workpiece on open pocket)
    
    G21 (using mm)
    G40 (manual toolrad comp)
    
    (Operation config)
    #<z-safe> = 20 (safe height)
    #<z-feed> = 0.25 (depth feed steps)
    #<toolrad> = 4
    #<feedrate> = 200
    
    (Workpiece params)
    #<wp_width> = 15
    #<depth> = [10 + 1] (1mm safety margin)
    #<bevel> = 3
    #<wp_length> = [93.8 - #<bevel>]
    
    #<steps> = [#<depth> / #<z-feed> * 0.5]
    
    G00 X0 Y0 Z[#<z-safe>]
    
    G00 Y[#<wp_length> * 0.5 + #<toolrad> - [#<bevel> + #<toolrad>]] X[#<wp_width> * 0.5 + #<toolrad>]
    
    #<current_depth> = [#<depth>]
    
    O101 repeat [#<steps>]
    
        #<current_depth> = [#<current_depth> - #<z-feed>]
    
        G01 Z[#<current_depth> - 2] F[#<feedrate>]
       
        G03 X[#<wp_width> * 0.5 + #<toolrad> - [#<bevel> + #<toolrad>]] Y[#<wp_length> * 0.5 + #<toolrad>] I[[#<bevel> + #<toolrad>] * -1] F[#<feedrate>]   
        G01 X[#<wp_width> * -0.5 - #<toolrad> + [#<bevel> + #<toolrad>]] F[#<feedrate>]   
        G03 X[#<wp_width> * -0.5 - #<toolrad>] Y[#<wp_length> * 0.5 + #<toolrad> - [#<bevel> + #<toolrad>]] J[[#<bevel> + #<toolrad>] * -1] F[#<feedrate>]
       
        #<current_depth> = [#<current_depth> - #<z-feed>]
    
        G01 Z[#<current_depth> - 2] F[#<feedrate>]
       
        G02 X[#<wp_width> * -0.5 - #<toolrad> + [#<bevel> + #<toolrad>]] Y[#<wp_length> * 0.5 + #<toolrad>] I[[#<bevel> + #<toolrad>]] F[#<feedrate>]
        G01 X[#<wp_width> * 0.5 + #<toolrad> - [#<bevel> + #<toolrad>]] F[#<feedrate>]
        G02 Y[#<wp_length> * 0.5 + #<toolrad> - [#<bevel> + #<toolrad>]] X[#<wp_width> * 0.5 + #<toolrad>] J[[#<bevel> + #<toolrad>] * -1] F[#<feedrate>]
    
    O101 endrepeat
    
    G00 Z[#<z-safe>]
    
    (Return to Origin)
    G00 X0 Y0 Z[#<z-safe>]
    %
    
    Haven't tested it yet, but looks good in simulation.
    And the code for the smaller bed, to put the unit on its side and mill the front bevel.

    Code:
    %
    
    (Creates a nice bed to place the workpiece)
    
    G21 (using mm)
    G40 (manual toolrad comp)
    
    (Operation config)
    #<z-safe> = 20 (safe height)
    #<z-feed> = 0.5 (depth feed steps)
    #<toolrad> = 4
    #<feedrate> = 200
    
    (Workpiece params)
    #<width> = [10 + 0.5] (2 x .25mm margin for workpiece)
    #<length> = [93.8 + 0.5] (2 x .25mm margin for workpiece)
    #<depth> = -2
    
    G00 X0 Y0 Z[#<z-safe>]
    
    
    (Corners)
    
        G00 X[#<width> * 0.5] Y[#<length> * 0.5]
        G01 Z[#<depth>] F[#<feedrate>]
        G00 Z[#<z-safe>]
    
        G00 X[#<width> * -0.5]
        G01 Z[#<depth>] F[#<feedrate>]
        G00 Z[#<z-safe>]
    
        G00 Y[#<length> * -0.5]
        G01 Z[#<depth>] F[#<feedrate>]
        G00 Z[#<z-safe>]
    
        G00 X[#<width> * 0.5]
        G01 Z[#<depth>] F[#<feedrate>]
        G00 Z[#<z-safe>]
       
    (Return to Origin)
    G00 X0 Y0 Z[#<z-safe>]
    
    (Square)
    
        G00 X[#<width> * 0.5 - #<toolrad>]
       
        G01 Z[#<depth>] F[#<feedrate>]
       
        G01 Y[#<length> * -0.5 + #<toolrad>] F[#<feedrate>]
    
        G01 X[#<width> * -0.5 + #<toolrad>] F[#<feedrate>]
       
        G01 Y[#<length> * 0.5 - #<toolrad>] F[#<feedrate>]
       
        G01 X[#<width> * 0.5 - #<toolrad>] F[#<feedrate>]
       
        G01 Y0 F[#<feedrate>]
    
        G00 Z[#<z-safe>]
       
    (Return to Origin)
    G00 X0 Y0 Z[#<z-safe>]
    
    %
    
    I still need to write the code for the front bevel. If you want to use this code please note that there is a lot of room for optimization and higher accuracy left!
     
  9. Front bevel code, not tested only simulated:

    Code:
    %
    
    (Creates the second bevel on the front side)
    (flip workpiece with closed pocket facing down on the clamped side)
    
    G21 (using mm)
    G40 (manual toolrad comp)
    
    (Operation config)
    #<z-safe> = 20 (safe height)
    #<z-feed> = 0.25 (depth feed steps)
    #<toolrad> = 4
    #<feedrate> = 200
    
    (Workpiece params)
    #<wp_length> = 93.8
    #<wp_width> = 10
    #<depth> = [15 + 1] (1mm safety margin)
    #<bevel> = [10 + #<toolrad>]
    
    #<steps> = [#<depth> / #<z-feed> * 0.5]
    
    G00 X0 Y0 Z[#<z-safe>]
    
    G00 Y[#<wp_length> * 0.5 + #<toolrad> - #<bevel>] X[#<wp_width> * 0.5 + #<toolrad>]
    
    #<current_depth> = [#<depth>]
    
    O101 repeat [#<steps>]
    
        #<current_depth> = [#<current_depth> - #<z-feed>]
    
        G01 Z[#<current_depth> - 2] F[#<feedrate>]
       
        G03 X[#<wp_width> * 0.5 + #<toolrad> - #<bevel>] Y[#<wp_length> * 0.5 + #<toolrad>] I[#<bevel> * -1] F[#<feedrate>]   
       
        #<current_depth> = [#<current_depth> - #<z-feed>]
    
        G01 Z[#<current_depth> - 2] F[#<feedrate>]
       
        G02 X[#<wp_width> * 0.5 + #<toolrad>] Y[#<wp_length> * 0.5 + #<toolrad> - #<bevel>] J[#<bevel> * -1] F[#<feedrate>]
    
    O101 endrepeat
    
    G00 Z[#<z-safe>]
    
    (Return to Origin)
    G00 X0 Y0 Z[#<z-safe>]
    %
    
     
  10. Hey couchsofa. Some really nice work there. I applaud your work in making your own hardware. Cool stuff.

    What I wanted mention was the practicality of a multiscale fretless. A few years back I built a multiscale 4 string, headless fretless. If you do a search with my username you'll find the build thread for it. It sounded amazing, but it was almost impossible to consistently play in tune. I've played upright and fretless for over 20 years but I couldn't manage even after a weeks solid practice on it. It was 34-31" across the 4 strings.... And that was with good fret markers.

    A good friend bought it but pretty much never plays it. It's an expensive curio now really.
     
  11. Thanks :D

    That's a shame. 3" in scale difference would roughly equal 76mm ... quite some angle on the frets!
    I'm going for 15° at nut and bridge, with a 15 - 9mm string spacing that gets me ~37mm in difference over 6 strings. Plus a bit of a margin on the notes form the extra long scale (although that might not add up to a lot).
    Hopefully that increases playability enough to make it work.
     
  12. Code ran fine but vibration triggered an endstop and caused the cutter to move into the unit :/ Took out 3mm of the workpiece so I adjusted the code to take off 3mm more on the front.
    I'm now at 90mm total length, 30mm for tuning and ~30mm for intonation adjustments ... I think it's enough room to work with.

    tumblr_nf94v5VqJf1twvu9io3_1280.png

    LabNews: the lasercutter is up and running :D Soon it will be cutting guitar templates!

    tumblr_nf94v5VqJf1twvu9io1_1280.png tumblr_nf94v5VqJf1twvu9io2_1280.png
     
  13. Yeah I had a look and I have to say I'm a bit concerned but on the other hand really want to build this thing. It would be a shame if the playability is really that bad but the whole endeavor is about learning, experience and building basses!
    For me, building instruments is a way to relax, lean back and go a bit crazy :D
    So it will be a success no matter what happens but you got me worried :/
     
  14. Well you're in the design phase, so STOP! What you can do is mock up a plank of scrap timber with some strings, tuners and bridge on in the right scales. It doesn't have to be fancy, it just has be good enough to play. Adding some sort of pickup will make it easier to hear. Draw on some line markers with a marker pen. Then try playing it in tune for a week or so. If you... and other bass players you know, have no dramas playing it in tune, then go ahead and build your dream. Otherwise, you need to rethink. Personally, I'd just fret the bass... which is another alternative. I built a multiscale fretted 6 string last year and it's a joy to play.
     
  15. Harry Cahyadi

    Harry Cahyadi Commercial User

    Apr 11, 2013
    Clayton, VIC, Australia
    C Basses Owner & Builder
    I did pretty much what he said. Started of with this 5 string, 37-32" multiscale lined fretless plan. Cut the body, cut the neck, cut the slots for the lines and, all of a sudden, I thought, how the heck am I gonna play this in tune. At that point I decided to put frets on it :).
     
  16. Right, removing the veneer and installing frets is an option, I guess. Certainly sounds like a plan: starting with veneer, see how it plays and adding frets if it's really that bad.
    I wanted to try a multiscale bass at our local music store but they didn't have one, so I have no reference (hmm, thinking about it ... I have no reference at all, only ever played basses that I built myself :D).
     
  17. Subd
     
  18. Drilled holes in the tuner cases yesterday.

    tumblr_nffqoqIWnz1twvu9io1_1280.png

    I used a larger drill to create a sloped pocket for the screw head. Screwed up one hole, drilled right through because it was very hard to gauge the depth on the 1,14mm thick brass while it slowly curved away from the drill ... oh well, gonna use a bigger screw :)

    tumblr_nffqoqIWnz1twvu9io2_1280.png

    Here are the pieces, pretty good for doing it by eye. Still need to manufacture the other parts and do some finishing on fine wet sandpaper, I'm also thinking about a lacquer finish ...

    tumblr_nffqoqIWnz1twvu9io3_1280.png
     
    Geoff St. Germaine likes this.
  19. Today I made some progress. Sunk the screws with a proper tool and cut the template in some 6mm ply with our nice new laser cutter :D

    tumblr_nfm4mezB9F1twvu9io2_1280.png
    tumblr_nfm4mezB9F1twvu9io1_1280.png

     
    Geoff St. Germaine likes this.
  20. 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.

     
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