Key Bitting MACS and Adjacent Cut Check

Because two adjacent cuts too far apart leave no metal between them. MACS -- the maximum adjacent cut specification -- is the rule, and it exists because a key's cuts are angled flats: two adjacent cuts at very different depths have their slopes intersect below the top of the blade, so the metal that should sit between them is not there. The cutter either breaks through or leaves a fragile ridge that fails in service, usually inside a cylinder, which is the expensive way to find out. A 3-8-1-5-4-6 bitting against a MACS of 7 has differences of 5, 7, 4, 1 and 2: cuttable, though the 8-to-1 transition sits exactly at the limit and will look dramatic on the blade. Change one digit -- 2-9-1-4-6-3 -- and the 9-to-1 transition is a difference of 8, which exceeds MACS by one and CANNOT BE CUT. The correction is to raise the third cut to 2 or lower the second to 8, either of which changes the key's operation, so it is a design correction to make in the bitting list rather than a decision for whoever is standing at the machine. A violation is a system design problem more than a cutting one. In a master key system the progression generates bittings automatically, so a progression that does not respect the rule produces uncuttable change keys somewhere in the sequence -- which is why the whole list is validated before any cylinder is pinned. Two related checks travel with it: a long run of identical depths produces a key that is easy to decode and to impression, and the shallowest cut at the shoulder position leaves the key weakest where it is worked hardest. Neither is a MACS matter and both are looked at in the same moment. A check against a value the user supplies. MACS, the depth increment, the allowable range, root spacing, and cut angle are manufacturer and keyway specific, and a value used for the wrong keyway gives a confident wrong answer. This layout covers a six-position bitting. It does not verify that a bitting is appropriate for a system -- that it does not conflict with a master, does not cross-key another cylinder, and follows the intended progression -- and it does not address key blank selection, keyway restriction, the controls on duplicating restricted keys, or high-security, dimple, sidebar, and electronic systems. The manufacturer's cut specification, a qualified locksmith, and the facility's key control policy govern.

for every adjacent pair, the absolute difference between cut depths must not exceed the manufacturer MACS value; the shortfall on a failing pair is that difference less MACS.

The maximum adjacent cut specification rule by name, with the lock manufacturer's cut specification named as governing the value, the depth increment, the allowable range, root spacing, and cut angle.

Absolute differences on a bitting the user enters, against a value from the manufacturer; no cut specification is reproduced.

Estimate. AHJ and licensed professional govern.

Field names used by the API: depth_1, depth_2, depth_3, depth_4, depth_5, depth_6, macs, min_depth, max_depth, max_difference, worst_position, failing_pairs, at_limit, longest_run

• The rule is about metal, not arithmetic adjacent slopes intersect below the blade top and there is nothing left between the cutskey cutting practice
• Validate the whole bitting list a progression that violates the rule produces uncuttable keys somewhere in the sequencemaster keying practice
• The value is keyway specific a MACS used for the wrong keyway gives a confident wrong answermanufacturer cut specification