Robeson pocket knives were stamped with a five digit pattern number, sometimes with a letter prefix or six digit number from about 1915 to 1999. The first digit signified the handle material; the second digit, the number of blades; the third digit, the Liner and Bolster material; and the remaining two or three digits, the Factory Pattern Number.

First number or Letter- Handle Material:

0 – Metal (Aluminum, Stainless Steel)
1 – Black Cocobola Wood, Black Composition
2 – Rosewood, Walnut
3 – Polished Black Composition
4 – Ivory Celluloid
5 – Saw Cut Bone, Gold Filled Metal, Stag, Saw Cut Delrin
6 – Bone, Rough Jigged Black Plastic, Jigged Delrin
7 – Pearl, Abalone
8 – Multi-Colored Celluloid, Single Color Celluloid
9 – French Pearl Celluloid, Christmas Tree Celluloid, ShurWood, Gun Metal
C – Celluloid
G – Gold

Second Number – Number of Blades

Third Number – Liner and Bolster Material:

0 – Combination Handle, Liner and Bolster
1 – Steel Liner and Bolster
2 – Brass Linder and Bolster
3 – Nickel Silver Liner and Bolster
5 – Special
6 – Iron Liner and Bolster or Iron Bolster
8 – Steel Frame Liner and Bolster
9 – Stainless Steel Liner and Bolster

Fourth, Fifth and Sixth Numbers – Factory Pattern Number:

Two or three digits indicating knife model.

½ Suffix:

Usually indicates a modification to an already introduced pattern. Examples are the addition of a bail or change from a clip to a spear blade.