The Birmingham YCL1340GH comes with a 30t, 40t, and a 127/120 double gear, which allow most common inch and metric thread pitches. These additional change gears will allow you to cut nearly any pitch that exists. For example, The stock gears don't allow for 1.25mm, 2.5mm or 5mm threads. With the gears arranged 30/127 x 120/36, you can cut all of those pitches. And many more.

19.3mm bore, 5.35mm x 2.55mm key slot

Includes one each:

30t

32t

36t

50t

60t

66t

Should also work for the Grizzly G4016, Shop Fox M1019, Jet Ghb1340 and any other version of the older Norton gearbox equipped 13x40 lathes with the double speed lever on the headstock.