External Tooth Lock Washers are a hardened circular washer with twisted
prongs or "teeth" which extend out from the outer edges of the washer. The
external tooth lock washer offers the greatest locking efficiency since the
teeth are on the largest radius and provide greater torsion resistance.
Internal Tooth Lock Washer Zinc Plated
Internal Tooth Lock Washers have "teeth" extend inward from the inside edge
of the washer and is preferred when the teeth must be hidden under the head of
the screw. Also recommended for use with screws with small heads.
Internal/External Tooth Lock Washer Zinc Plated
Combination Tooth: the "teeth" protrude from both the inside and outside
edges of the washer. Use this washer under the following circumstances.
Where a large bearing surface is desired.
For an optimum electrical connection.
Where the hole is oversized or put of round.
As an insert between two adjustable pieces where a longitudinal or
rotational adjustment must be maintained.