I am going to have to agree with those suggesting Gotoh. The Sperzels are fine gears, and the quality is very high. I don't have anything negative to say about them (which, if you know me, is high praise), but the Gotoh 510 series of gears, if you can find them, is the nicest thing on the market, bar none. They make them with the locking mechanism, and they are excellent. If you can find them (which is difficult) you will be very happy with them. Strangely, the place with the widest retail selection I have found is the wood and metal machinery importer Grizzly. Their new president is a guitar maker, and he has them selling wood and parts for guitars.
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