Plane Mark
Definition
A surface trace left by a hand or machine plane, showing the arc of the blade stroke and any irregularities such as nicks. In Koehler's analysis, a nicked blade on a specific planer in a South Carolina mill left a repeated ridge pattern on the ladder rails that could be matched back to the machine.
- Cause
- Hand or machine plane blade stroke on a surface
- Diagnostic feature
- Arc pattern and blade irregularities such as nicks
- Notable case
- Lindbergh kidnapping ladder evidence
- Comparison method
- Matching repeated ridge pattern to a specific tool
Common questions
What made the plane mark evidence in the Lindbergh case forensically strong?+
The nicked blade on the specific planer produced a repeated, individual ridge pattern on the ladder rails that investigators could trace back to one machine in a South Carolina mill, giving toolmark evidence rather than only a general match to plane marks in general.
Can plane marks be matched to a tool even without the original blade nick?+
A clean, undamaged blade leaves only class characteristics common to many similar planes, so individualisation to one specific tool generally requires a distinguishing defect like a nick, chip, or wear pattern unique to that blade.
Related terms
- Crossgrain
- A condition in which the wood fibres run at an angle to the long axis of the piece. In Rail 16, Koehler...
- Grain Matching
- The physical comparison of growth-ring pattern and fibre direction at a fracture or cut surface to an adjacent piece of wood. Because...
- Rail 16
- Koehler's designation for the left side rail of the bottom section of the Lindbergh ladder. The rail that was matched by grain,...
- Supply Chain Tracing
- In Koehler's investigation, the process of tracking the ladder lumber from the sawmill of origin through the distribution network to the retail...
- Tool-Mark Analysis (Wood)
- Examination of surface marks left by cutting, planing, or shaping tools to identify the tool type, size, and individual characteristics of the...