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Tuner Identification

Discussion in 'Setup & Repair [DB]' started by jsf729, Jan 19, 2017.


  1. jsf729

    jsf729 Supporting Member

    Dec 12, 2014
    Central Maryland
    Hoping to acquire some knowledge about characteristics of tuning machines from various areas of the globe as well as time of production. I've studied pictures on the classifieds, but don't know enough to tell the difference. Plus composition material is even harder to decipher from pictures.
    Also would appreciate pros and cons if applicable. Thanks in advance!
     
  2. Ortsom

    Ortsom Banned

    Mar 23, 2016
    Not entirely certain what sort of discussion you're after, but here are some pointers for starters:
    • Gear ratio. Indicates how many turns the flapper (handle) will make before the peg makes 1 turn. Common ratio's for DB, with 14mm OD pegs, is around 1:26 or 1:27. If you go finer (=higher number, like 1:30), adjustment is in principle more accurate, but practically the benefit is small due to friction of the string on the nut. For steel core strings on a 14mm peg I find anything just above 1:25 suitable, for more stretchy synthetic or gut you can go lower. Count the number of teeth on the sprocket (cog): for a common single-thread worm, one full rotation of the worm (& flapper) rotates the sprocket by 1 tooth, hence the number of teeth on the sprocket gives the gear ratio.
    • Peg OD. When the peg makes 1 full rotation, it pulls in 1 x the peg's circumference (+ a bit, depending on the string OD) of string, so the peg OD also determines the tuning sensitivity. For a thinner peg you could get the same tuning sensitivity with a lower gear ratio. But beware: bending a thick string round a thin peg can cause the core to break (there was a recent thread where that happened). Historical wooden DB pegs are typically 18-19mm OD, but modern metal DB pegs seem to converge towards the 14mm OD EBG 'standard' as introduced by Fender/Schaller. That 14mm normally doesn't give many problems (that I know of), but the 'slim line' or 'light' EBG-style tuners with thin pegs (8?, 9? mm) that are being used in some EUB's to me seem less suitable for DB strings. Furthermore, thinner pegs come with thinner peg-sprocket joints, which are weaker & less suitable for the higher tension in DB strings (typically close to double that of EBG strings). Of course, normal DB tuners have the peg supported on both sides in the pegbox (with the worm below the sprocket), and I believe 14mm is the smallest they come in (if not the only size).
    • Peg shape. Historically tapered, like in violins & cello's, and still commonly so in the upper range, also for DB. But nowadays cylindrical 14mm pegs are also common.
    • Sprocket (cog) size. The bigger the sprocket, the lower the forces between sprocket & worm. With the tension forces in particularly steel DB-strings, small EBG-style sprockets (typically 22mm OD) may cause the worm not last as long as with bigger DB-style sprockets (typically OD 35mm or more).
    • Tuner type. Common DB tuners have the peg running all the way across the pegbox, and the peg is then supported on both sides (and the worm is below the sprocket). This is advisable for DB string tension, particularly steel strings. EBG-style tuners have the peg supported on just 1 side, with the peg held using cantilever forces (and with the worm above the sprocket). It works, for some time, and is used in several EUB's, but in my opinion it is structurally inferior to the conventional DB construction. But of course that requires a bigger pegbox. So a design compromise.
    • But most important of all is the fitting. Even the best up-market ($1000) machine can run poorly if not fitted properly, while even the cheapest ($50) DB machine can run well if fitted well. For plate-type tuners it is important that the axle of the peg is purely perpendicular to the plate when fitted, so that it is stressless & does not grind when everything is tight, and of course with well fitting pegs. But also french-style plateless tuners benefit from that orientation (so the axle of the sprocket is aligned purely perpendicular to axle of the worm, and the worm properly positioned), allowing proper contact between the teeth & the worm.
     
    DoubleMIDI likes this.
  3. jsf729

    jsf729 Supporting Member

    Dec 12, 2014
    Central Maryland
    That is great info Ortsom. Thank-you! More to the point though, I'm interested in info for how to visually identify -for example- a German tuner machine from a French, or Italian. I've noticed that some members here- you being one of them- have a great knowledge of this. The physics of the tuner that you graciously contributed is appreciated though.
     
  4. Ortsom

    Ortsom Banned

    Mar 23, 2016
    No I don't. To me, 'French style' tuners just means that there is no plate connecting the worm & peg, not even a small one. Then the forces between sprocket & worm are carried by the wood of the pegbox cheek. And 'Tyrolian' means it has a big plate covering the entire cheek, but I may be wrong.
     
    DoubleMIDI likes this.

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