1.1.3 Mechanical Joint: Keyway
Keyways transmit torque between a shaft and gear by means of a rectangular key secured to the shaft by dowels, pins or set screws. Machining costs for tolerances required by keyways may be significant. The diameter of a shaft in which a key is seated must be increased by up to 30% to accommodate the key while supporting the torque load.
![](/en/manuals/bonding/assets/img/cylindrical-joint-fastening-methods.jpg)
![](/en/manuals/bonding/assets/img/key-keyway-shaft-fastening-methods.jpg)
![](/en/manuals/bonding/assets/img/key-keyway-shaft-fastening-diameter.jpg)
1.1.4 Mechanical Joint: Folding or Clinching
Two pieces of sheet metal can be connected to each other by folding or bending tabs in the form of a buckle and a clamping slot in a folded joint. This assembly method is relatively quick, reliable, economical and convenient.
However, folded metal joints do not seal and may be susceptible to corrosion. These types of joints require a relatively long contact area to provide strength and are not suitable for plastics.
![](/en/manuals/bonding/assets/img/mechanically-folded-joints-sealing-4.jpg)
![](/en/manuals/bonding/assets/img/mechanically-folded-joints-sealing-5.jpg)
![](/en/manuals/bonding/assets/img/mechanically-folded-joints-sealing-6.jpg)
![](/en/manuals/bonding/assets/img/mechanically-folded-joints-sealing-7.jpg)