lockerKeys/key_bittings.py

from dataclasses import dataclass

MM_PER_IN = 25.4


# A progression of root depths, decreasing by a constant amount each step.
def linear_depths(start, end, base, increment):
    return {str(depth): base - (depth - start) * increment
            for depth in range(start, end + 1)}


def depths_in_to_mm(depths):
    return {name: depth * MM_PER_IN for name, depth in depths.items()}


@dataclass
class BittingSpecification:
    key_thickness: float
    root_cut: float
    included_angle: float
    positions: int
    TFC: float  # To First Cut (center)
    BCC: float  # Between Cut Centers
    depths: dict[str, float]


# https://www.lockreference.com/wp-content/uploads/2019/03/Yale-Disc-Tumbler.pdf
yale_disc = BittingSpecification(
    key_thickness=0,  # TODO
    root_cut=.044 * MM_PER_IN,
    included_angle=90,
    positions=5,
    TFC=.125 * MM_PER_IN,
    BCC=.095 * MM_PER_IN,
    depths=depths_in_to_mm({
        "1": .250,
        "2": .230,
        "X": .220,  # also called "7"
        "3": .210,
        "4": .190,
        "5": .170,
    }))

# https://www.lockreference.com/wp-content/uploads/2018/01/Yale-.019.pdf
yale_019 = BittingSpecification(
    key_thickness=0,  # TODO
    root_cut=.054 * MM_PER_IN,
    included_angle=95,  # 110, 95, or 86
    positions=7,
    TFC=.200 * MM_PER_IN,
    BCC=.165 * MM_PER_IN,
    depths=depths_in_to_mm(linear_depths(0, 9, .320, .019)))


# https://www.lockreference.com/wp-content/uploads/2018/01/Yale-.025.pdf
yale_025 = BittingSpecification(
    key_thickness=0,  # TODO
    root_cut=.054 * MM_PER_IN,
    included_angle=95,  # 110, 95, or 86
    positions=7,
    TFC=.200 * MM_PER_IN,
    BCC=.165 * MM_PER_IN,
    depths=depths_in_to_mm(linear_depths(0, 7, .320, .025)))

# https://www.lockreference.com/wp-content/uploads/2018/09/National-Disc-Tumbler-Single-Sided.pdf
national_disc_tumbler = BittingSpecification(
    key_thickness=2,
    root_cut=.044 * MM_PER_IN,
    included_angle=90,
    positions=6,
    TFC=.156 * MM_PER_IN,
    BCC=.093 * MM_PER_IN,
    depths=depths_in_to_mm(linear_depths(1, 4, .250, .025)))