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taper size for machines

Discussion in 'Setup & Repair [DB]' started by Matthew Tucker, Feb 28, 2008.


  1. Matthew Tucker

    Matthew Tucker Commercial User

    Aug 21, 2002
    Sydney, Australia
    Owner: Bresque Basses, Sydney Basses and Cellos
    Is there a standard taper for tapered DB machine heads? I have three examples here, all different models, but all the same taper (.0336)

    Its not a morse taper, is it?

    Is it a standard machine taper or is it something quircky only for DB machines?

    I want to make sure I get the right reamer, if I lash out for one.
     
  2. Matthew Tucker

    Matthew Tucker Commercial User

    Aug 21, 2002
    Sydney, Australia
    Owner: Bresque Basses, Sydney Basses and Cellos
    No-one uses taper reamers?? So what do you use?
     
  3. 1st Bass

    1st Bass

    May 26, 2005
    Forest Grove, OR
    I had to make my own...and it wasn't that great. I think, on my next bass (this one, actually, as I am a long way from installing tuning machines), I will turn grade-8 bolts to the correct taper and length, for each tuning machine taper (they are not the same), and then use an abrasive cut-off wheel to cut a slot or two in each. That will make a satisfactory reamer, and as infrequently as they will be used, it will probably work as long as I am likely to need such tools.

    The last one I made by heating a file white-hot, and twisting it into a helix, then grinding the taper, and sharpening it. It looks cool, hanging on my tool-rack, but was not that good, in actual use. I can think of things I could have done to improve it, but...the bolt idea would probably work fine, for less trouble.

    I suppose if one had a cheap source of twist drills of the appropriate size, one could simply grind the appropriate taper, and the helical flutes would already be in place. The taper is the same for all four tuners, but the lengths are different, and in my case, they do not go all the way through, so I had to have four separate reamers. as it necessitated four different lengths and diameters.
     
  4. RCWilliams

    RCWilliams Commercial User

    Apr 23, 2007
    Merriam Kansas (Kansas City)
    owner RC Williams Co. LLC
    try googling a 1,30 or 1:30 taper pin reamer, the .0336 almost equates to a standard violin peg taper but the diameter may be an issue. and if you know of a source for machine mountable 1:17 reamers let me know.
     
  5. Matthew Tucker

    Matthew Tucker Commercial User

    Aug 21, 2002
    Sydney, Australia
    Owner: Bresque Basses, Sydney Basses and Cellos
    I worked out that a number 4 Morse taper is about 1:19, I think that might be close enough for endpins.

    But for machines - last time I ground down some spade bits, but that really wasn't satisfactory. Though I only needed a taper really for the thick end, for the bottom end it was satisfactory just to drill a hole with the right size twist drill, about 3-4mm deep.
     
  6. 1st Bass

    1st Bass

    May 26, 2005
    Forest Grove, OR
    Now that's a good point-- I wonder why I never thought of that. I will simply shorten my home-made reamer a bit, and it will probably be acceptable...and still look cool on the tool board. :)
     

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