Key versatility was improved in 1786 with the introduction of a circular, notched bolster housing a swivel to which the claw was attached by a short screw pin. The swivel allowed placement of the claw in incrementally different positions that were held by a spring catch built into the shaft. By repositioning the attached claw, the instrument could be used to draw a left or right, upper or lower tooth. And, with the claw positioned parallel to the shaft, the key would have moved most effectively in an up or down direction, functioning more like a pelican instrument.
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Notched Bolster Key
The handle and claw designs of this key (A147.164) make it a more flexible instrument than earlier examples.
University of the Pacific Permanent Collection,
Donor: Maurice J. Owens, DDS
Square-Ended Shaft
Held to a squared-ended shaft by a thumbscrew, the ebony handle can be quickly removed and turned 90 degrees.
Spring Catch on Shaft
Its spring-loaded shaft pin allows faster reversal of the same claw, for left versus right extractions, or exchange of variably sized claws.
Slots in Bolster Swivel
Adding to its versatility, a spring catch and slots in the bolster swivel allow the claw to be placed quickly in one of three positions of 90 degrees difference.
