Ignition Advance Unit NSN 2920-00-040-0498

Internal involute spline data'number of teeth 20, diametral pitch 16/20, pressure angle/at given pitch diameter/20 degrees, circular pitch 0.1963 in., base circle diameter 1.1746 in., chordal space width 0.0981 in./machine to 0.981-0.1002/permissable backlash 0.002 to 0.006 in. When meshing with mating spline, tooth spacing error referenced to pitch line 0.003 in. Between adjacent teeth, 0.0007 in. Cumulative index, teeth to be parallel with axis within 0.0002 in. Per in. Of length, dim cir space width 0.1003 in., min dim cir space width 0.0982 in., min eff cir space width/with gage/0.0975 in., 1.1094-1.1012 in. Between 0.10497 in. Diameter pins, american bosch part number gr-5221-a fscm 01843

2920 Nonaircraft Engine Electrical System Components

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