Lap joint flange has a curved radius at the bore and face to accommodate a lap joint stub end. The lap joint flange and stub end assembly are normally used in systems requiring frequent dismantling for inspection. They are used on piping equipped with lap joint stub ends or with lapped pipe. These flanges slip over the pipe and bolting pressure is transmitted to the gasket by the pressure of the flange against the back of the pipe lap. Lap joint flanges have certain special advantages: freedom to swivel around the pipe facilitates the lining up of opposing flange bolt holes and the lack of contact with the fluid in the pipe often permits the use of inexpensive carbon steel flanges with corrosion resistant pipe or tubing. The stub is welded to the pipe and the lap joint then works as a backing ring. The main advantage of this type of flange is that the bolt holes can be aligned with the matching flange after the welds have been completed. They are primarily used on carbon or low alloy steel piping systems. They are also used in the erection of large diameter or hard-to-adjust piping configurations because of its quick bolt hole alignment.

Lap Joint flanges are used on piping equipped with lap joint stub ends. It is used at all pressure levels and is available in full size range. These flanges slip over the pipe and are not welded. The bolting pressure is transmitted to the gasket by pressure of the flange against back of the pipe lap. It permits the use of carbon steel flanges with corrosion resistant pipe. It is machined with flat face and fillet radius accommodates stub end or pipe lap.

Lapping & polishing machines are used to smooth and polish the surface of any solid material. It allows finishing any surface to nanometer thick nesses. A lapping or polishing machine creates a very smooth or flat surface with an extremely fine finish.

Lapping plates are used to smooth out heads that read the disks of hard disk drives in computers. Lapping is the process of rubbing the heads on the lapping plates, in a sense sanding the heads smooth.