Thank you for the dating information on my 2 line 119.
...it dates '67 to '69 because it has bone hard fiber spacers. The two line stamp did date '67-'71 but in '69 Buck transitioned to micarta spacers...
I find the phrase "
bone hard fiber spacers" confusing. Are the spacers bone or fiber?
Like Joe said it's a type of gasket material and not "bone". Bone hard fiber is vulcanized fibre and is a laminated plastic composed of only cellulose. The material is a tough, resilient, hornlike material that is lighter than aluminium, tougher than leather, stiffer than most thermoplastics.
The process started with paper made from cotton rags. Before the processing of wood pulp and chemical wood pulps in the mid-19th century, the dominant fibre source for paper making was cotton and linen rags.
Once the paper plies were saturated with the gelatinizing zinc chloride, they were pressed together. The pressing allowed intimate contact of the Cellulose fibers, thus promoting bonding between the cellulose chains.
Once the vulcanized fibre is leached free of the zinc chloride, it is dried to 5 to 6 percent moisture, and pressed or calendared to flatness. The continuous process-made vulcanized fibre could then be sheeted or wound up into rolls. The density of the finished vulcanized fibre is 2 to 3 times greater than the paper from which it starts. The density increase is the result of 10% machine direction shrinkage, 20% cross machine direction shrinkage, and 30% shrinkage in thickness.
The final product is a homogeneous nearly 100%-cellulose mass free from any artificial glues, resins, or binders. The finished vulcanized fibre has useful mechanical and electrical properties. It offers high tear and tensile strength, while in the thinner thicknesses allowing flexibility to conform to curves and bends. In thicker thicknesses, it can be moulded to shape with steam and pressure. One application for vulcanized fibre that attests to its physical strength is that it is the preferred material for heavy sanding discs. The electrical properties exhibited by vulcanized fibre are high insulating value, and arc and track resistance with service temperature of up to 110 to 120°C. Vulcanized fibre shows high resistance to penetration by most organic solvents, oils, and petroleum derivatives
Commercial Grade; standard grey, black or
red, used for many applications such as washers, gaskets, gears, handles, etc.
Electrical Grade: high dielectric grey, 100% cotton, very flexible, (historically called fishpaper), this grade is suitable for layer and ground insulation and has variations including top-stick grade used for wedges in small motors.
Trunk Fibre: Tough and abrasion resistant; used to surface steamer trunks, drum cases, wear and skid panels.
Bone Fibre: Exceptionally hard and dense, used for tight machining, tubing, pool cue ferrules (tips), cut out fuses.
Wood Laminating: Tough, multi-directional tensile and torsion strength, provides support and strength wherever wood laminations are used, particularly used under thin and exotic veneers as a stabilizer/strengthener.
