Pitch selection for Hacksaw Blade:
For soft materials such as bronze, brass, soft steel, cast iron, heavy angles etc. use a 1.8 mm pitch blade.
For tool steel, high carbon, high speed steel etc. use a 1.4 mm pitch. For angle iron, brass tubing, copper, iron pipe etc. use a 1 mm pitch blade.
For conduit and other thin tubing, sheet metal work etc. use a 0.8 mm pitch.

The grade of file tool is listed below
1. Rough
2. Bastard
3. Second Cut
4. Smooth
5. Dead Smooth

1) Rough File : A rough file is used for removing rapidly a larger quantity of metal. It is mostly used for trimming the rough edges of soft metal castings.

2) Bastard File: A bastard file is used in cases where there is a heavy reduction of material.

3) Second Cut File: A second cut file is used to give a good finish on metals. It is excellent to file hard metals. It is useful for bringing the jobs close to the finishing size.

4) Somooth File: A smooth file is used to remove small quantity of material and to give a good finish.

5) Dead Smooth File: A dead smooth file is used to bring the material to accurate size with a high degree of finish.

Jenny caliper is also called as Hermaphrodite caliper.

There are exactly two tangents to a circle through a point lying outside the circle