I’ll weigh in on tuning pin depth and similar issues.

I agree with Bill that you have to have awfully scrawny pins to twist on their axes. The ones that used to be supplied by Zuckermann for a 4’ register really were too thin and twisty, but the slightly thicker ones I use show none of this problem. My “standard” 8’ pins (the only larger ones I use are for wound strings on big clavichords, and those are indeed monsters) are 4.1mm thick, and my top-octave thinner 4’ pins are 3.8mm thick. Neither twists on its axis, with a proper tuning hammer and good technique.

As for how deep. This is intertwined with the issue of hole diameter. I learned eventually that a too-tight hole means that the pin does not seat very deeply into it, and is, as a consequence, not well secured. And there is a special issue with instruments that require a very tall tuning pin up near the 8’ nut in the bass, where the nut is high and the string comes off the pin very high on it. This requires a significantly greater length of pin down in the hole in order to provide leverage against the pull of the string and its risk of tilting the pin towards the tail (“flagpoling”). If this happens, the hole gets elongated in an egg shape and you are in trouble. This issue is one reason I prefer to make my own tuning pins, because I have control over their length, and can make a small set of extra length for that situation in the bass, ensuring a long bit of pin down in the hole. As much as 50% of the total length of the pin in some cases. In general my “standard” pins are 50mm long and the set I use for the bass on instruments like the big Zell are maybe around 55 or even 60 long, and go pretty deep into the block.

To back up, though, I learned quite a long time ago that a larger hole can make a more secure tuning pin simply because it allows more length of pin down into the wrestplank. For what it is worth, with my 4.1mm pins I use a  #22 drill bit (diameter 3.99mm according to a chart I just looked up) and with around 10-14mm of pin down in the hole, the pins hold very firmly but turn smooth as silk. I don’t remember the drill size for my smaller pins. I may use a #27 for the 3.8mm pins (3.66mm).

In all cases I  now use brad-point bits for these holes in order to avoid or at least minimize the cosmetic unpleasantness of tearing out when the bit enters the wrestplank. On non-veneered walnut planks, used on Italian harpsichords, the risk of tearing isn’t that great, though even here the brad-points cut more cleanly at the top and can be more accurately positioned, but with spruce or fir veneer, the risk is quite high. I finally learned that if I run a pilot scoring by running the bit for a second backwards, the holes will be clean as can be. This will only work with a brad-point bit with a center spur and annular scoring ring.

Normally, brad-point bits, at least in North America, can only be obtained in imperial-inch sizes, in widely spaced fractions, but I found a company (W. L. Fuller) which sells brad-point bits in so-called “wire-gage” diameters, very reasonably priced. Here is their link:  http://wlfuller.com/html/brad_point_drills.html

By the bye: my “standard” 4.1mm tuning pins are made from ordinary 16d bright common nails, the smaller ones from 10d bright commons, and those monsters for big-clavichord wound strings from 20d (4.88mm) bright commons.

hope this can be made helpful

owen

ps: back to depth: basically, once you have determined a tuning pin and hole size you like, the depth will pretty much take care of itself. You drive in the pin until it is secure but moves smoothly. Doesn’t need to be over-thought.


____________________________________


Owen Daly Early Keyboard Instruments
557 Statesman St. NE
Salem, OR 97301
http://www.dalyharpsichords.com
(503)-362-9396

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