Woodruff key is a semi-circular disc & fits into circulars recess in the shaft, which is machined by Woodruffs keyway cutter. The shaft may be parallel or tapered, showing the method of dimensioning shafts for the Woodruff key where the depths of the recess from the outsides of the shaft are given, in addition to the diameter of the recess.
Woodruff keys have the advantage that they will turn themselves into their circular recess to accommodate any tapers in the mating hub on the assembly; For this reason, it cannot be used as a pawn key, as it would jam
Woodruffs keys are commonly used in machine tools and, for example, between the flywheel and crankshaft of a small internal combustion engine, where the drive depends largely on the fit between the shaft and the conical rugged flywheel hub.
The keyway in the shafts is a semi-circular pocket, the mating parts, a longitudinal slot. They are used to improves the concentricity of the shafts & mating part, which is important for high-speed operation. The circular section can be cut directly by plunge cutting with a circular woodruff cutter without any relief.
The main advantage of Woodruff keys is the elimination of milling near the shaft shoulders, where stress concentrations and concentrations would be affected. A more precise fit of the key and keyway also reduces play and stress concentrations and improves the reliability of the key.
The Woodruff keys is a semi-circular disc and fit into a circular recess in the shafts, which is machined by a Woodruffs keyway cutter. These Woodruff keys are mostly used in machines, tools & automobile shafts ” to 2½” (6 mm to 60 mm) in diameter. Woodruff keys are not capable of bearing the same weight as long parallel keys.The advantage of the Woodruff key is that it is able to accommodate any taper in the hub keyway, its captive and depth preventing the key from turning over. Disadvantageous or drawbacks of woodruff keys are that the depth of the keyway weakens the shaft, cannot be used as a feather key, is difficult and small to install. Installing two or more Woodruff keys to lift the bulk of the load is expensive and makes installation more problematic.
Advantages of Woodruff Key:
Here, the different advantages of woodruff key are as follows
- This is an easily adjustable key.
- This hub is capable of accommodating any taper in the keyway,
- This is a more precise fit of the key and also reduces keyway play and stress concentrations, and improves the reliability of the key.
- This ends milling near the shaft shoulders, where stress concentrations and concentrations will be affected.
- This is especially important for high-speed operations.
- This harness is useful at the ends of the shafts. Its extra depth in the shafts prevents any tendency for it to overturn in its keyway.