Reverse tuners

[artdeco]

I have three sets of mid-range Schaller F5 tuners on hand. Two of them turn clockwise to tighten the strings and one set turns counter-clockwise to tighten the string. So, am I to understand that the counter-clockwise units are 'normal', and the clockwise units are 'abby something'? (sorry for the Marty Feldman reference).

[Paul Hostetter]

If it doesn't turn like this, regardless of whether the worm is over or under, it's simply wrong.



I have some sets of gears out and will attempt to find time to photograph them to elucidate this better. Among them is an older ('70's) set of Gotoh F gears, worm under, that turn the wrong way!

Quoting me:

On the left are the modern gears. Note the direction of the worm gears. On the right are the so-called "reverse" gears. The cog is of course unchanged.

John says:

I beg to differ. Most quality tuners have sloped teeth on the cogs, to match the slope of the worm. In that case, right-hand and left-hand cogs are not interchangeable.

You're right, but you're also missing my point. But with luck I can take some photos that will make it clearer.

[siminoff]

This is an interesting thread. Tony had initially asked about the history of key direction and I’d like to offer some info there. For string instruments with side-tuning machines (as opposed to straight peg and friction peg instruments), it was traditional that strings were tightened by turning the knob counterclockwise for both bass-side and treble-side knobs. All of Gibson’s mandolins (and banjo mandolins) tuned this way until 1978. In 1978, when we were launching the new F5-L mandolin (first shown at the June 1978 Chicago NAMM Show), the only manufacturer of mandolin machines available to us at the time was Kluson Mfg, a small, but important Chicago-based machine manufacturer that started making machines in 1925 and was sold to new owners around 1985. At the time, they were producing mandolin machines that turned properly, but were “inverted” – that is, the worm was above the round gear. Their machines had a left-hand thread worm. On special order, Kluson would assemble the machines upside down so that the worm gear was below the round gear (they didn’t want to re-work their tooling to cut the worms right-hand). While the machines had the F5 look (well, almost), they turned backwards. Neither Schaller nor Gotoh were prominent in mandolin machines at the time, and the few other mandolin machines on the market didn’t have the right look, so the only choice we had to go with for the F5-L was the wrong-turning Klusons. So, for a few years of production, the F5-L Gibson mandolins tuned backwards. For whatever reason, many of the import look-alikes that emerged during the past past 20 years were also cut with a left-hand worm and when assembled worm below round gear, they turned backwards. Today, to the best of my knowledge, only Gotoh makes both inverted and regular machines that both turn correctly (their inverted machines have a left-hand worm and their regular machines have a right-hand worm). So, it actually was by “decision” that the machines (at least the F5-Ls of the late 1970s) tuned backwards - we really didn’t have another choice at the time.

Regarding backlash, I agree with Paul’s comments. The problem wasn’t really with gear backlash as much as it was with post binding. In the early machines, the posts were fitted into snug holes in the peghead and the edge of the hole was dressed up with an eyelet. The eyelet didn’t provide much of a bearing surface and as a result the posts would hang up in the hole and the musician could turn the knob slightly one way or the other and feel what appeared to be “backlash” but was actually the string post not turning at all. So, by inverting the machines – putting the worm on top of the round gear – and having a tighter fit of the round gear into the worm gear, the result would be reducing backlash but not really solving the post binding problem. The improvement came when bushings were used rather than eyelets, and the string post holes were drilled to the outer diameter of the bushing. In this way, the post never touches the wood and only bears on the backstrap and the bushing which provides minimal friction and basically eliminates the apparent backlash problem.

Best,
Roger