Thrust screws are also called positioning screws, support bolts and thrust screws. They are a type of bolt used to fix the relative position of machine parts. When in use, screw the set bolt into the screw hole of the machine part to be fixed, and press the end of the bolt tightly against the surface of another machine part, even if the former machine part is fixed on the latter machine part. Slotted and hexagonal set bolts are used on machines where the bolt head is not allowed to be exposed, and square head set bolts are suitable for machines where the bolt head is allowed to be exposed. The clamping force of the bolt is the smallest for slotted bolts, the largest for square head bolts, and the hexagonal bolts are in the middle. Cone-end bolts are suitable for machines with low strength; non-pointed cone-end bolts are suitable for machines with pits on the clamping surface to increase the ability to transfer loads; flat-end bolts (the clamping surface should be flat) and concave-end bolts are suitable for machines with high hardness or frequently adjusted positions; long cylindrical end bolts are suitable for tubular shafts (on thin-walled parts, the cylindrical end enters the hole of the tubular shaft to transfer a large load, but there should be a device to prevent the bolt from loosening when used.)