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IML- RESI PD  400 Resistograph

The Resistograph is a device used to identify and access the extent of decay and defects in trees. The instrument is essentially a battery-powered drill with an extremely fine bit (1.1mm diameter with a flat 3mm tip). The bit is driven into the tree up to a depth of up to 400mm. The energy required to drive the bit into the tree is measured and a graph is produced displaying the distance traveling into the wood on the x-axis and the amplitude (the torque) on the Y-axis. By examining the changes in torque required to propel the bit into the wood, it is possible to detect wood weakened by decay, cavities, cracks, and other defects.   


Resistograph In Use

Resistograph readout

Resistograph Readout

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