Casstrom No.10 SFK Curly Birch Sleipner Leather Fixed Blade Knife

A knife with a Full-Tang construction, representing the first project of the Swedish brand Casstrom and at the same time one of the most recognizable bushcraft models from this manufacturer. Equipped with a Drop-Point blade profile with a length of 103 mm, made from wear-resistant Sleipner tool steel, and handle scales crafted from natural Curly Birch wood, also known as figured birch.

The model was designed for demanding outdoor tasks – from precise wood processing to heavier survival and camp work. The materials used and the full-length tang running through the entire handle ensure high durability. The No.10 SFK knife was refined over the years until it reached its final form, which gained recognition among outdoor enthusiasts looking for a reliable field tool. The set includes a leather sheath.

The knife is made from a single piece of Sleipner tool steel developed by the Swedish foundry Uddeholm and hardened to a hardness of 59-61 HRC. The material combines exceptional abrasion resistance with high resistance to cracks and chipping, which is a hard-to-achieve yet highly desirable combination for models intended for heavy work. The steel used is significantly less prone to corrosion compared to typical low-alloy tool steels.

In the model, a Drop-Point blade is used, with a smooth cutting edge and a length of 103 mm. The blade is fashioned with a Scandinavian (Scandi) grind, particularly valued in bushcraft knives. This type of geometry is well-suited for whittling or batoning wood and preparing kindling.

Proper balance of the blade leads to better control over the knife. The weight is distributed evenly between the blade and the handle, ensuring higher cutting precision and reducing hand fatigue during prolonged work. The blade is finished using the satin method.

The handle consists of scales with an ergonomic shape screwed onto the tang, made from oiled Curly Birch wood. The oil impregnation helps protect the material from moisture and dirt. At the end of the handle, there is a lanyard hole allowing for threading of a strap or safety cord.

The properly contoured handle shape provides a stable grip, improves knife control, and reduces hand fatigue during precise tasks. Curly Birch is valued both for its durability and distinctive appearance, resulting from the irregular grain pattern of the wood. 

The set includes a brown sheath with a drainage hole made of vegetable-tanned leather, which protects the blade during transportation and storage of the knife. The construction allows comfortable carrying on the belt, providing quick access during fieldwork.

Natural leather is characterized by very good resistance to intense use, and over time, it gradually develops a characteristic patina highlighting the field nature of the equipment. This process is a typical feature of natural leather and does not negatively affect its durability or usability.

• knife with Full-Tang construction
• Drop-Point blade measuring 103 mm
• Uddeholm Sleipner tool steel
• material hardened to a hardness of 59-61 HRC
• high resistance to abrasion, cracks, and chipping
• Scandinavian Scandi grind
• blade finished with satin method
• proper balance improving work precision
• handle made of Curly Birch (brzoza kędzierzawa) wood
• ergonomically contoured grip
• oil-impregnated wood
• lanyard or safety cord hole
• leather holster made of vegetable-tanned leather
• drainage hole in the sheath 
• possibility of convenient carrying on the belt