Rule of thumb in evaluating gear mesh 

Builders

A quick guide on gear tooth clearance;

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No blood = too loose.

Aircraft Mechanic passes out = too tight.

Moderate bleeding = acceptable clearance.

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Note to builders: When turning engine over by gripping flywheel, avoid the 10 and 2 O’clock grip because it puts the right thumb very close to the point where the starter and ring gear mesh. Proper mesh clearance is set with a 1/16″ drill in in a separate operation, thumb is not an accepted substitute for 1/16″ drill.

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-ww.
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