3D printing Longhorn bass pointer knobs? ideas?

Discussion in 'Hardware, Setup & Repair [BG]' started by tommy cass, Aug 19, 2020.

  1. tommy cass

    tommy cass

    Dec 18, 2016
    I'm curious if anyone on here has any experience with 3D printing guitar parts.
    Im needing a set of the knobs found on Longhorn basses.
    Danelectro doesn't sell them and the plain round type are OUT OF STOCK.
    A Dano page poster measure his set and I have measurements but I don't have a printer or the know how.
    ANY suggestions welcomed.
    thanks T
  2. tommy cass

    tommy cass

    Dec 18, 2016
    Ill take that as a FIRM no lol
  3. RSBBass


    Jun 11, 2011
    Most 3d plastic printers will use plastic that will be too soft to be useful for knobs.
  4. Hachimitsu


    Jun 6, 2019
    New Zealand
    I think the originals were wooden? Better bet may be to find a cabinet maker or similar that will do it for you. If you have the measurements and multiple photos, it shouldn't be a problem
  5. Arie X

    Arie X

    Oct 19, 2015
    "Most 3d plastic printers will use plastic that will be too soft to be useful for knobs."

    not true. you can print a variety of resins suitable for knobs. make your way over to thingiverse and hit up one of the designers.
  6. JKos

    JKos Supporting Member

    Oct 26, 2010
    Torrance, CA
    Not true at all.

    @tommy cass ,
    An important question is what type of shaft do they go on?
  7. Bruce Johnson

    Bruce Johnson Commercial User

    Feb 4, 2011
    Fillmore, CA
    Professional Luthier
    I would make them by resin casting, rather than 3D printing. It's the way we make up bobbins and other plastic parts for making pickups. You hand carve a master part from wood or plastic or even modeling clay. Make a silicone rubber mold from it. Then make the knobs by pouring polyurethane casting resin in the silicone mold.

    With any kind of knob, you have to figure out how to do the center hub that locks onto the pot shaft. It can be smooth 1/4" bore with a side setscrew, or a serrated bore. Like JKos asked, what kind of pot shafts do you intend to put these on? Most knobs have an aluminum or brass center hub that is molded into the plastic.

    One way to make custom knobs like these is to modify existing knobs. Buy some knobs that are a little smaller, then add a plastic shell on to them to get the look that you want.
    JKos likes this.
  8. My son has printed some knobs for me before. They wont be as smooth as metal ones (IE: there will be printer lines on them) and I've never tried to sand one, but they are possible to print. He printed some knurled type knobs that looked really good.

  9. pravus


    Feb 5, 2013
    Denver, CO
    I have friends that have been doing 3D printing for years now and this should be easily possible with some caveats.

    You will need to either find or create a 3D model for the knobs. There are sites where people post these or drawing/CAD programs to create them. Once you have a model picked out you feed it into a processing pipeline to convert it to a set of instructions that are used to move the motors on a 3D printer much in the same way that CNC machines work. There are a lot of subtle steps here to get the model optimized for printing but anyone with experience with 3D printing should be able to help. Knobs should be extremely easy in this regard since they are a plain surface with no holes or internal structure.

    There are multiple plastics that can be used for printing in a variety of colors. Each of these materials has different hardness and shrinkage properties and people experiment with new materials all the time. For example, there are now high-end exotic car parts using sintered metal printing with rare materials for their heat characteristics. Again, someone with experience in 3D printing can help choose a material because they probably have experience working with several and you can also do your own research.

    The prints themselves can vary in quality depending on how well the model is converted, the materials used, and the resolution of the gears in the stepper motors that move the print head. Current technology can get very detailed prints but many of them will have a rough finish and potentially small imperfections at the edges or in lettering/numbering. You will need access to a semi high-quality 3D printing rig to get good finishing results and even then you might need to print multiple batches and experiment with different final finishing methods if you don't like the way the plastic prints look. You are essentially gluing thin, melted layers of plastic together so the process always has a certain element of slop to it.

    Resin prints have an almost smooth finish and every one I've seen are extremely high quality because they use a laser to cure layers of resin on top of one another. However, the resin itself never hardens completely and always has a mushiness to it. My personal opinion is that this would be the way to go if you don't mind the feel. It's also possible that other resins might be available that fully harden when cured but I'm not as familiar with these. It seems like resin printers are newer and rarer but that might just be my perception.

    Anyway, that's a long-winded way to say, yes it is possible. Based on the image you gave I think it would be easy to get the knobs made but you'd have a hard time getting them to look exactly right because the originals were probably cast in a mold and all of the edges are rounded and soft. The nice thing about 3D printing though is that it is generally cheap to do experiments so it might be worth getting a few made just to give yourself an idea of what's involved.
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    Primary TB Assistant

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