The main difference between the three bench planes is the length of the sole plate and this determines how accurately wood can be planed flat and straight in theory the longer the better. The jointer plane is just less than 600mm long, the jack plane from 350 to just less than 400mm and the smoothing plane about 230mm. Jointer planes are not very widely used and of the other two the jack plane probably offers the best comĀpromise of properties.
The blade on a bench plane does not usually cover the full width of the plane so it cannot be used for trimming close to an edge. The blade is screwed to a cap iron and inserted bevel side down. The cap iron is clamped with its edge just behind the cutting edge – the optimum distance setting varies somewhat with the type of wood and the shaving thickĀness, but is typically 1 to 1.5mm. The cap iron breaks the shaving immediately it is cut and this gives a smoother surface and makes the wood less likely to split. The blade and cap iron are held into the plane body at an angle of 60 degrees to the sole plate by means of the wedge iron. The depth of cut can be adjusted by turning a small knob, which governs how far the blade protrudes from the sole plate. Finally, the blade can be aligned so that it cuts evenly over its whole width by using an adjusting lever. To make sure that the blade is set correctly, look along the sole plate from the front end and move the lever until the blade protrudes evenly.
When using a bench plane, always make sure that the wood is held firmly. When planing with the grain, try to make a continuous cut along the whole length of the timber. Apply pressure to the front of the plane when you start the stroke and the back of the plane when you finish it. When planing end grain, cut from each side towards the middle. It is possible to cut off one corner first and plane towards it, but if you take off too much with a stroke, the wood is likely to split on the far side. When planing thin edges or chamfers, guide the plane with your fingers, so that the same portion of plane blade is used over the whole cut.
At frequent intervals when using the plane (and also before storing it), clean out all shavings and sawdust. Never rest a plane on its sole plate, always rest it on its side, and store it by hanging it up in a dry place.