What is a Bandsaw and do you need to use one
A bandsaw uses a long sharp blade consisting of a continuous band of toothed metal rotating on opposing wheels to cut materials such as wood. Although Allwood only sells woodworking bandsaws they can also be used for metal working and lumbering, but could possibly cut a wider variety of materials.
The advantages of using a band saw include uniform cutting action because of the evenly distributed tooth load, and the ability to cut irregular or curved shapes.
Most bandsaws have two wheels connected by a belt or chain rotating in the same plane, one of which is powered. The blade can come in a variety of sizes which enables this machine to be highly versatile.
The blades are mounted on wheels large enough not to cause fatigue because of the flexing that happens when the blade changes from a circular profile to a straight profile. The larger bandsaws need to have a deformation worked into them that counteracts the forces and heating of operations, known as benching. They also require servicing at regular intervals.
The shape of the tooth gullet is highly optimised and varies depending on the type and condition of the wood you need to cut.
Head Saws are large bandsaws that make the initial cuts in a log. They have a 2 to 3 inch tooth space on the cutting edge and sliver teeth on the back. Sliver teeth are non-cutting teeth designed to wipe slivers out of the way when the blade needs to back out of a cut.
Resaws are a large bandsaw optimised for cutting timber along the grain to reduce larger sections into smaller sections or into veneers. Resawing veneers requires a wide blade commonly 2 to 3 inches with a small kerf to minimise waste.
Double Cut Saws have cutting teeth on both sides. They are generally very large, similar in size to a head saw.
Gravity Feed saws - this saw falls under its own weight, but adjustments can be made to the cutting force with a counter balance.
Hydraulic Feed saws use a pressure hydraulic piston to power the saw through the timber, set at variable pressures and rates.
Screw Feed saws use a leadscrew to move the saw.
Pivot saws hinge in an arc as they move through the timber
Single column saws have a large diameter column that the entire saw rides up and down on.
Dual column saws have a pair of large columns, one on either side of the timber. Dual column saws are the largest variety of machine bandsaws encountered.
Common Tooth Forms
Precision blade gives accurate cuts with a smooth finish
Buttress blade provides faster cutting and large chip loads.
Claw tooth blade gives additional clearance for fast cuts and soft material.
There are also automatic bandsaws which have features such as preset feed rate, return, fall , part feeding, and part clamping. These tend to be used in production environments where having a machine operator per saw is not practical.
Do you need a Bandsaw
A hobbyist would only need a small bandsaw, which will reduce the amount of physical energy he/she would use cutting the wood with a hand held tool.
Larger organisations such as a timber mill use very large bandsaws for ripping lumber as they produce very little waste and saw on labour hours.