On ebay now Fairchild tin with two cutting stylii in USA
http://cgi.ebay.co.uk/Fairchild-Record-Cutter-Stylus-/260756484293?pt=Vintage_Electronics_R2&hash=item3cb64c30c5
ebay: Fairchild cutting stylii
Moderators: piaptk, tragwag, Steve E., Aussie0zborn
There need not be any relationship at all between the tin and the stylii. The tin is interesting, because it says "With 4 deg Offset Flat". This shows that the stylii that were originally in the tin were made for cutting equipment without suction: the swarf was thrown to the side, most likely towards the centre where a brush on the nut collected it.
This fixed offset was the equivalent of rotating the cutting stylus in its holder. This means that the signal in one flank of the groove precedes that in the other, and it means that ideally, if you use an elliptical stylus for reproduction, that also should be rotated in the cantilever. You may use stereo reproduction with a conventional elliptical stylus, but you cannot use simple adding, but need to shift one channel in time, and variable at that.
This fixed offset was the equivalent of rotating the cutting stylus in its holder. This means that the signal in one flank of the groove precedes that in the other, and it means that ideally, if you use an elliptical stylus for reproduction, that also should be rotated in the cantilever. You may use stereo reproduction with a conventional elliptical stylus, but you cannot use simple adding, but need to shift one channel in time, and variable at that.