Parallel Key and Keyway Calculator (DIN 6885)
Look up the standard parallel key section, shaft and hub keyway depths for a given shaft diameter per DIN 6885, then check the bearing stress on the keyway for your torque and load type. Covers shafts from 6 to 110 mm.
Advertisement
How to use this calculator
- Enter the shaft diameter to get the standard key section b x h and keyway depths t1 and t2.
- Enter transmitted torque and the effective key length to check bearing stress.
- Select the load type to compare against a typical allowable stress.
Frequently asked questions
What key fits a 45 mm shaft?
Per DIN 6885 the shaft range over 44 to 50 mm takes a 14 x 9 key with shaft keyway depth t1 = 5.5 mm and hub keyway depth t2 = 3.8 mm.
How is keyway bearing stress computed?
Sigma = 2 x T x 1000 / (k x L x d) where k is the smaller of the two contact heights (h - t1) and (h - t2), L is the effective length and d the shaft diameter.
Why does the calculator use the smaller contact height?
The shaft side and hub side of the key do not both fill their keyways completely because the depths sum to more than the key height. The smaller contact area governs.