Robert Sorby varekatalog Robert Sorby catalogue 2018-2019

54 Chisel Sharpening Most bench chisels are made from carbon steel. This gives them a keen cutting edge. For this reason we recommend you keep the edge in perfect condition with regular visits to the sharpening stone. The Robert Sorby ProEdge also offers a sensational method for sharpening chisels and is particularly good at re-proﬁling damaged tools quickly and efﬁciently. We suggest using in combination with your favoured stone method. Nowadays there is a wide selection of different stones for the woodworker – ranging from natural Arkansas stones, to the popular Japanese waterstones, and to the more modern diamond impregnated and ceramic stones. All of these are available in different sizes – you should choose the size of stone most suitable for the size of chisel to be sharpened. Such stones are normally used in conjunction with a lubricant – either a special honing oil or water. Like plane irons and spokeshave blades, bench chisels normally have two bevels. The honing or micro bevel is traditionally 5˚ greater than the grinding angle. This imparts greater strength to the razor-sharp edge. ‘Robert Sorby has redeﬁned the standard bevel angles on its traditional carpentry chisels (see diagram) to match the harder timbers more frequently used by those purchasing our chisels. We now use 25 degree primary bevel and a 30 degree secondary bevel for tools that leave the factory. A primary angle of 20 degrees and a secondary of 25 degrees, traditionally used on soft woods like pine and frequently seen on UK site work is still recommended for this type of work. Corner Chisels - sharpen each face individually using an oil stone with a good square edge. Draw Knife - hand lap using ﬂat clean oil stone. You know it is time to sharpen your chisel when scratch marks appear on the workpiece or when cutting becomes ever more difﬁcult. Another useful tip is to hold your chisel up to the light. A sharp edge does not reﬂect the light. Soft Woods Main Bevel angle 20º Honing Bevel angle 25º For soft woods such as the pine, cedar, ﬁr and redwood Hard Woods STANDARD BEVEL ANGLES Mortice Chisels 30˚ Framing Chisels 30˚ Bevel Edge Chisels 25˚ Paring Chisels 20˚ Main Bevel angle 25º Honing Bevel angle 30º Bench chisels leave the factory sharpened to these angles Carving Tool Sharpening A good quality carving tool is made from high carbon steel and will sharpen down to ½ micron – at least four times sharper than a razor blade. The bevel should be ﬂat or convex – never concave. Traditionally carving tools have been sharpened on Arkansas or Washita stones but these take time despite the good ﬁnish. Japanese waterstones are popular and give rapid and ﬁne sharpening ﬁnishes but these can be expensive. An array of mechanical processes is available, but we do not recommend using a bench grinder to sharpen carving tools as this will produce an unwanted hollow grind. You also run the risk of blueing the edge and softening it by raising the temper which can irrevocably damage your tool. The Robert Sorby ProEdge offers a system that will put a razor sharp edge on tools in seconds. We recommend that carving tools are sharpened little and often on a ﬂat disc with a ﬁne abrasive before ﬁnishing on a leather or felt disc impregnated with polishing compound. Our honing kit was designed for this purpose and comes complete with all the necessary components. The honing kit can be driven off almost any electric motor. The recommended bevel angle will vary with preference but generally speaking for light cuts in soft woods such as lime, a bevel angle of 15 degrees will cut cleanly. Increase this angle to 20 or 25 degrees for harder woods. Finally always ensure the internal ﬂutes of carving gouges are polished to ensure clean cuts. This can be achieved on a shaped felt or leather honing wheel ensuring that the wheel is rotating away from the cutting edge. A blunt edge reﬂects light - sharp ones do not. Remove inside burr with very ﬁne (600 grit) wet & dry paper wrapped around a shaped stick 1000 grit - sharpening 6000 grit - polishing Very ﬁne abrasive discs for sharpening - leather discs for polishing

Robert Sorby varekatalog Robert Sorby catalogue 2018-2019 | Page 54