What are the acceptable deflection limits for shafts carrying gears and bearings?

For shafts with gears, lateral deflection should be less than 0.01 x module at gear location to prevent uneven tooth contact. Angular deflection at gear should be less than 0.05 degrees. At bearings, angular deflection should be less than 0.04 degrees for ball bearings and 0.1 degrees for roller bearings. For precision machinery, limits are halved. Excessive deflection causes gear noise, vibration, bearing damage, and premature failure. Use Macaulay's method or FEA for deflection analysis.