How Tsuboe products are made
A grater from Tsuboe starts life as a flat sheet of metal and passes through twelve steps in the family workshop in Tsubame before it is sent out into the world. Behind every step lies a simple ambition: to make the finest oroshigane – the Japanese grater – with honest craftsmanship and the best possible sharpness and comfort in use. Read about the workshop's history in About Tsuboe.
Honmetate – the pride of the workshop
Traditionally, every tooth on a grater was raised on its own with a chisel – a technique called honmetate. Tsuboe has held on to it and, after many trials and together with a machinery maker, developed its own NC machine that reproduces the technique and precision of the hand. This precise, complex arrangement of teeth is the foundation of the flagship Gokujo, and the workshop's finest graters have grown out of exactly this technique.
Twelve steps from sheet to grater
1. Blanking
Production begins with each product's shape being punched out of the sheet in a press. Tsuboe works in copper, stainless steel, aluminium and titanium, and every sheet arrives with a protective film on one side. Even at this stage, the workshop takes a series of small precautions to keep scratches and dirt off the metal.
2. Flattening
After blanking, each piece is flattened in a press. It looks like a simple step, but it matters: the smoother the surface, the better the tooth striking that follows.
3. Drilling
Holes are drilled in the handle, and the staff check by eye that they sit precisely, both vertically and horizontally.
4. Stamping
Once the holes are drilled, the company name is stamped into the metal. The piece is now ready for tooth striking.
5. Tooth striking – honmetate
This is where the grating surface itself is created. Most mass-produced graters have all their teeth pressed in a single stroke, while Tsuboe's NC machine raises each tooth on its own. More than any other step, this one determines the grater's sharpness, durability and quality.
6. Forming
The flat piece is shaped in three dimensions in a press with purpose-made dies that add edges, recesses and angles. The dies are designed so they do not damage the freshly struck teeth.
7. Polishing
Polishing evens out differences in colour and small irregularities in the surface, removes burrs from blanking and gives either a gloss or a matte finish. Copper handles can discolour during processing, and this too is corrected here.
8. Washing
Oil, dust and metal residue from processing are washed off. The pieces lie in divided baskets so the grating surfaces do not touch and get damaged, and afterwards everything is checked by eye to make sure it is clean.
9. Laser marking
Depending on the product and material, Tsuboe chooses between stamping and laser marking. The flagship Gokujo series is marked by laser.
10. Final inspection
Every single product is inspected individually, usually under a loupe. The closest attention goes to the grating surface, where even small dents or damage are rejected. At Tsuboe, quality is not only a matter of technology but also of the eyes of experienced inspectors.
11. Packing
The products are placed in cases or wrapped in protective material.
12. Shipping
Even the cardboard boxes are checked for dirt and dents before they leave – a damaged box can take something away from the experience of what is inside.
A workshop that makes room for precision
Care, precision and a strict final inspection call for a well-designed workspace. Tsuboe uses trolleys on castors that spare the body and save needless steps, and a clean, orderly workshop has made the whole production more efficient. A good working environment also brings motivation and room for new ideas – which Tsuboe sees as an important part of building the brand.
Three series – each with its own story
The best sharpness takes time, and Tsuboe's graters are the result of generations of work on functional beauty. To secure the workshop for the next 100 or 200 years, Tsuboe has gathered its own products into three series. The name Gokujo – "the supreme" – expresses confidence in the history of oroshigane and the honmetate technique. Gokujo and SHIRO put sharpness and comfort in use at the centre, while irogami adds colour. Each series has its own role and its own story.
Responsible manufacturing
Tsuboe places weight on manufacturing that takes the environment and society into account. The packaging for all the workshop's own series has been redesigned to remove unnecessary wrapping, and the workshop is gradually moving to plastic-free packaging.
