IIsakki Järvenpää Company manufactures it's handicrafts themselves from finnish materials in their own factory at Kauhava.
Materials, machines and working methods have been established decades ago and are currently not planned to be changed.
As hilt's materials we mainly use birch, which is delivered to us from Central Finland and Häme. The birch is delivered to factory as so called scabbard sawn planks, where the planks are dried to exactly right moisture for further processing. First it will be sliced to blocks which are then milled one by one to desired model's shape. During this process the blocks are sorted by birch pattern as different model's materials.
Another hilt material that we use is birch bark. Birch bark is being delivered from eastern Finland in 40x50 cm sheets. The sheets are worked one by one to different sizes for different knife models. In birch bark hilt's head accessories we use domestic glossy cardboard and leather in different colors and patterns. Birch bark hilts are crafted one by one, slip by slip for every knife's hilt, fully handicrafted. The bark is not glued or otherwise attached to each other, instead they are being held tightly together by riveting the whole hilt.
Every knife is grinded individually with belt sander to desired shape.
As blade's material we use special knife steel. The steel as material is exception to the domestics of knife because it is delivered to us by Thüssen Group from Germany in full sheets. However the materials might very well be delivered to there from Finland. The knife steel has been accurately processed to exact carbon and chromium content and this kind of material can't be accessed in same quality elsewhere. In 1980s blades were hot-forged but back then materials used were old files and even earlier old horseshoes. The carbon quantity for those products were increased by hitting blade with dropping hammer (also known as "heijari"), which removed waste products from the material. Nowdays blades are being pressed from fully uniform and correct mixture ratio steel sheet. Afterwards the blade reforms are tempered and grinded one by one, both sides of the blade individually. In the end blades are polished.
Inaddition we craft knives, scabbards, helavyö and necklaces from complete brass and silver sheet. Every hela requires multiple individual operations, 3 to 6 different stages each.
Naturally the leather of scabbards, belts and necklaces is delivered as whole hides from Central Ostrobothnia. Scabbard patterns and hela are all made in singular handicrafts.
Some models have single brass or bronze casted helas. Those are crafted to us by domestic handicraftsmen. We use the best subcontractors for different models and materials, all finnish.
Our knives are assembled from aforementioned materials individually in our factory at Kauhava, every single one. In our web pages we present some of the crafting procesess and assembly in videos.
The villagers and boys were amazed and in awe when a huge oddity rolled down the road in September, 1922. Alfred Kosola’s horses had to tax their strength when drawing a sleigh with an indenting hammer of 5.000 kilograms, along the snowless road to the Järvenpää’s factory. The cubs’ imagination really took over, when they began to hear a constant pounding from the factory. It was like an iron giant’s sledgehammer banging.