|Ripping and Mortising - Course: Manual Woodworking Techniques. Trainees' Handbook of Lessons|
6.1. Making Chamfers
If chamfers cannot be made by means of planing, ripping tools are applied to produce short narrow faces (chamfers) on the edges of wooden workpieces.
The method of schamfering is applied, e.g.,
- to avoid fraying of wood fibres at the bottom edges of the feet (legs) of tables, seating furniture, storage shelves and other products standing on the floor,
- to ensure a better insertion of the tenon into the mortise (in case of a hidden mortise and tenon joint).
Such chamfers are mainly made with a ripping chisel at the edges of end-grained faces.
1 chamfers at the bottom edges of a foot (leg), 2 tenon, 3 mortise, 4 end-grained faces
Chamfering with the ripping chisel involves the following sequence of operations:
- clamp the workpiece,
- cut off wood chips from the outside up to the centre of the edge. In doing so
· the cutting edge of the ripping chisel blade is pointed at the workpiece,
· the blade is guided at an angle of approx. 45° to the adjacent faces and with the grain,
- work the edge in the opposite direction up to the centre.
1 cutting off the wood chips, 2 working direction up to the middle of the edge
In order to avoid fraying of wood fibres, do not guide the ripping chisel outwards beyond the middle of the edge!
6.2. Cutting off Projecting Material Residues
When cutting off adherent residues of material made of wood or plies, the appropriate working method depends on
- the type of the respective material,
- the grain (with materials made of wood).
When working thin wood materials (veneers)
- with the grain, the working direction corresponds always with the ascending wood fibres;
- across the grain, the workpiece must always be worked from outside towards the centre, in order to avoid fraying of wood fibres.
1 in the direction of the ascending wood fibres, 2 across the grain
When working soft plastic materials the working direction is from the outside to the centre of the workpiece.
The cutting edge of the ripping chisel blade is pointed at the workpiece and is guided parallel to the working face. In doing so, pay attention that the surface of the workpiece is not damaged by the rip ping chisel blade.
1 cutting edge of the blade, 2 workpiece, 3 surface of the workpiece
6.3. Removing Adherent Glue Residues by Means of Ripping Tools
On completion of constructional gluing (i.e. making assembly groups and finished parts by sticking together wooden piece parts) glue residues - either still soft or hardened already - can be removed with the ripping chisel
- from the wide and narrow faces,
- from the corners.
1 glue residues, 2 workpiece surfaces, 3 workpiece corners, 4 ripping chisel blade, 5 acute angle
According to the different position of the glued joint and the possible working direction, the ripping chisel blade is brought up to the residual glue at an acute angle to the workpiece surface. In doing so, handle the tool with care, in order not to damage the workpiece surface.