Piston head key ways are sometimes given so little clearance that the key completely fills the keyway when driven fully home.
The sides and bottom of the keyway should be surfaced true with the file.
If a keyway is to be cut by hand through a bore, as in a pulley or gear-wheel bore, its width should be marked with a T-square.
This head is also driven by a key which engages a keyway in the boring-bar.
The rod end should be planed to thickness for the brasses and of equal thickness on each side of the keyway.
The flat key is used where it is necessary to secure the wheel more firmly without weakening the shaft by cutting a keyway in it.
A much more usual method, however, is to employ slotting or keyway drills.
The sleeve now stands still, the die cuts the thread and pulls the turret along by the friction of the pin in the keyway.
This causes the pin to catch in the front end of the keyway and the sleeve is again locked.
Fig. 1533 represents the chuck in use for holding a piece of shafting s to cut a keyway or spline in it.