Points per inch (ppi) refers to the number of saw teeth to the inch along the saw blade. Woodworking saws with a small number of ppi are suitable for cutting softwoods and those with a larger number should be used lor sawing hardwoods. The kerf is the name given to the width of the saw cut. The gullet is the distance between one saw tooth and the next. The gullet carries sawdust out of the kerf to make the task of sawing easier.
Hand saw.
There are 3 types of hand saw.
A. Rip saw.It is used for cutting softwoods ,working with the grain. The teeth are chisel edged to shave off the fibres of the grain. The large gullet carries the sawdust out of the kerf.
B. Cross cut saw. The saw is used to cut across the grain of hardwoods and softwoods and lor working with the grain on very hard woods. The knife point shaped teeth gives the sharper cut needed when working across the grain.
C. Panel saw. The panel saw is used for fine cross cut and jointing work and for cutting plywood, blockboard and hardboard. The teeth are a similar shape to those of a cross cut saw.
Double sided saw for cutting greenwood.
One side is flne toothed for cutting slender plants and the other has large open gullets to carry away sawdust when cutting larger timber.
Tenon or back saw.
It is used for jointing and for cutting across the grain on small pieces. The back may be brass or steel. The saw with 20 ppi is for cutting dovetails. Its blade is thin to give greater accuracy. All cuts made with a dovetail saw should be along the grain as it performs a ripping action.
Saw knife or pad saw with a keyhole blade. Metal keyhole saw blade. Both are used for cutting small irregular shapes in the middle of a board.
Flooring saw.
The rounded nose allows you to cut into floor boards without damaging adjacent boards.
General purpose saw.
The teeth are hardened and tempered. It is used for cutting wood laminates, plastic, mild steel, rubber, etc. It is a handy odd job tool but is not recommended for first class, accurate work. The handle is adjustable to enable work in awkward places and positions.
Coping saw.
It has very fine teeth and is used for cutting tight curves. Tension is applied to the replaceable blade by tightening the handle.
Fret or piercing saw.
It is similar to coping saw but is deeper to allow work with larger boards. There are many types of blade available, the choice depending on what material you wish to cut.
Junior hack saw.
General purpose saw for light metal work.
Adjustable frame hack saw.
It can take 254mm to 305mm blades. Blades are available in range of ppi from 14 to 32.
Sheet saw.
This is for cutting thicker building material such as insulation slabs and metal covered plywood. It is more accurate for cutting straight lines than general purpose saw.