WWII M1 125mm Howitzer Gears

Sometimes the individual parts are more interesting than the whole. These aiming gears are on a WWII M1 125mm Howiter on display in front of the Oshawa branch of the Royal Canadian Legion.

Here is a Google Maps satellite image of where this photo was taken or you can copy and paste the following coordinates into Google Earth:
43 53' 05.96"N, 78 51' 28.00"W