I bought a set of these for replacing the tuners on my MM Stingray. They are well designed and feel solid and dependable. However, I was very disappointed by the quality control.
Under the big cog is a slip of thin clear plastic, which helps the cog to glide smoothly as you turn the tuner head. Out of the four in the set, three tuners had that slip of plastic badly mangled and bent -- one was even slightly chewed up by the cog gear... ironically probably damaged by someone turning the tuner gear during a QC check, and not observing that the plastic film had slid into the cogs and gotten bent out of shape. The function of the plastic is to just ensure a smooth movement, but with enough turning these broken plastic slips just get so mangled that they impede the smooth movement of the gear, and eventually work themselves out of the mechanism entirely, leaving you turning metal on metal.
Fortunately, because these are a direct replacement of the stock MM tuner gears, it was easy enough to just transplant the plastic slips from the original tuners into the three that were mangled in this new set. But I shouldn't have to do that.
For Stingrays, if you don't want to drill holes in your headstock you pretty much have no other choice than these, and once they're installed (with undamaged plastic slips) they work really well and are solid and smooth. But, I'd highly recommend you carefully check those plastic slips and if possible, salvage the ones from your old set if you're doing a replacement. 1 undamaged out of 4 in a new set is not a good track record for quality control.
