Heel
The portion of the broad part without teeth in a file is known as Heel.
60 degree
The angle between the teeth and the centre line in single cut file is 60 degree.
A single cut file has rows of teeth cut in one direction across its face. The teeth are at an angle of 600 to the centre line. It can cut chips as wide as the cut of the file. Files with this cut are useful for filing soft metals like brass, aluminium, bronze and copper.
Half round
The shape of a rasp cut file is Half round.
Try square
The try-square is a precision instrument which is used to check the squareness of a surface and the flatness of surfaces.
Witness marks
Witness marks The line marked on metal surfaces is likely to be erased due to handling. To avoid this, permanent marks are made by placing punch marks at convenient mark intervals along the marked line. Punch marks act as a witness against inaccuracies in machining and hence, they are known as witness marks.
