The type of door that will work best for your shower depends on the design of your shower, the size of the opening and the practical space considerations that determine how your door should open. Showers generally fall into three types of designs.
Preload is the tension created in a fastener when it is tightened. This tensile force in the bolt creates a compressive force in the bolted joint known as clamp force. For practical purposes, the clamp force in an unloaded bolted joint is assumed to be equal and opposite of the preload.ither is acceptable, however a torque value defined for tightening the head does not necessarily apply to tightening the nut. Tightening the head vs. the nut can result in different nut factors and therefore change the torque required to achieve proper preload.
For torque controlled tightening whether the nut is tightened and the bolt head held, or the bolt head tightened and the nut held, can be of importance. The general objective from a tightening process is to achieve a consistent bolt preload.s more torque is perhaps needed to overcome friction, less remains for the bolt extension and hence as the effect of adversely reducing the preload. If the friction under the nut face is reduced, then, for a given torque, the bolt preload will be increased.