Sharpening of cutting tools
Aroldo Figueroa works alone at one bench in Manchester, by hand and on stones: kitchen knives for people who cook all day, scissors and shears that have been forced open and shut, and bench edges for woodwork that have to be flat before they can be sharp. The angle is set to the tool and to the work it does, not to one setting on a machine, and nothing is ground away that does not have to go.
The same edge twice over: the knife flat on the stone, and a section of it enlarged, where the two ground faces meet and the burr is raised before it is taken off.
Five families of edge, each with its own angle, its own grit sequence and its own way of failing. They are listed so you can tell before writing whether your tool belongs here.
01
Chef knives, boning and filleting blades, slicers, cleavers and paring knives, from kitchens where a dull blade costs an hour a shift. Stainless, carbon and laminated blades are treated differently, and so are the Japanese shapes that are ground on one side only.
Wire edge raised, turned and removed; the shoulder behind the edge thinned when a blade has been sharpened back so many times that it has stopped cutting deep.
02
Tailoring and fabric shears, barber and grooming scissors, kitchen shears, and the heavier garden and hedging kind. Each blade is ground on its own face, then the pair is checked closed: a shear that is sharp and still chews cloth is usually loose at the pivot or no longer touching along its length.
Pivot tension is reset and the ride line corrected, because the cut happens where the two blades pass each other, not only at the edge.
03
Chisels, plane irons, spokeshave blades, marking knives and carving gouges. The back is flattened first and that is the slow part; an edge is only a line where two flat surfaces meet, and a bevel honed onto a hollow back will never take a clean shaving.
Bevels are set square and to the angle the work needs: lower for paring, steeper for mortising and for hardwoods that chip a fine edge.
04
Leatherworking knives and skiving edges, bookbinding and paper knives, upholstery and carpet blades, hoof and farrier knives, and the long single-bevel tools that have to be kept true along a curve rather than a straight line.
Curved and hooked edges are worked on slips and rounded stones, by hand, because a flat wheel cannot follow them.
05
Chips, rolled tips, a point snapped off, a blade run along a steel until it is wavy, and the deep scratches left by a belt sander used too hot and too fast.
The profile is redrawn by hand and cooled constantly: steel that has been blued at the edge has lost its hardness there, and that part has to come off before a new edge is worth putting on. If too little blade is left for that, you are told rather than charged.
Four steps, whether it is one knife or a whole kitchen roll. Nothing is ground that was not agreed, and the price is settled before the first stone comes out.
The kind of tool, roughly what it is made of, what it cuts and what it is doing wrong. A photograph of the edge held against the light says more than a paragraph.
The edge is examined for chips, bend, hardness lost to heat and how much steel is left. You get a written note of what it needs and what it costs before work starts.
Coarse stone only where damage makes it necessary, then finer grits, then the burr off. Every edge is tested on the material it is meant for before it is wrapped.
What was done, the angle it was left at, what was deliberately not touched, and how to keep it that way for longer than a fortnight.
One bench, one pair of hands and a box of stones can do a great deal and cannot do everything. Said here rather than discovered after a tool has been handed over.
If yours is not answered here, put it on the request page and it comes back in writing, before anything is agreed.
As little as the damage allows. A blade that has only gone dull is honed and loses almost nothing you could measure; one with chips along the edge has to be taken back behind the deepest of them, and that is real loss of steel. The difference is told to you first, because it decides whether a tool is worth the work at all.
It comes back as sharp as its job wants. A paring knife and a carving gouge are finished keenly; a heavy cleaver or a hedging shear is left with more bite and a stronger edge, because a very fine edge on a tool that hits hard folds over on the first cut and is then worse than blunt.
No. A fast dry wheel removes metal quickly and heats the thin part of the blade most, and steel that turns colour at the edge has been softened there. Work here is done on stones, cool and by hand, which is slower and is the reason an edge keeps for longer afterwards.
Cut on wood or plastic rather than glass, stone or steel; wash and dry by hand instead of in a machine; store so the edge touches nothing; and straighten an edge with a smooth steel or a strop rather than a pull-through, which scrapes a new edge every time. Each tool goes back with a note on this.
Say what the tool is, what it cuts and what it is doing wrong. You get an answer in writing, with what the work would involve and what it would cost, before anything is agreed.