Addendum: I have done some math, which I will share here, but there are some many tension/torque/torsion hinges on the market, it is difficult to choose. Here is my math:
Mirror Dimensions: 12 5/8 x 66 1/2 inches
Weight estimates:
Weight of 3/4 inch plywood backing, at 2.3 lb/sq.ft. = 13.4 pounds
Weight of 1/4 inch mirror: 17.5 pounds
Weight of primer, mastic, mirror supports, etc. = 1 pound
Total weight = 32 pounds
Torque formula = Weight x CG distance x cos(angle)
(Because the weight is distributed evenly, the center of gravity in this case is 1/2 the 12 5/8 inches length, which is 6.3 inches.
TORQUE CALCULATIONS:
* 0 degrees (mirror held in place horizontally, like a shelf, which may not make sense for this application, but is the MAXIMUM torque necessary):
32 pounds x 6.3 inches x cos(0 degrees) = ANSWER: 211 inch pounds of torque
Two hinges = 105.5 inch pounds each. Three hinges = 70 inch pounds each.
* 71 degrees (current mirror angle):
90 - 19 degrees mirror angle = 71 degrees.
32 pounds x 6.3 inches x cos(70 degrees) = ANSWER: 69 inch pounds of torque.
Two hinges = 34.5 inch pounds each. Three hinges = 23 inch pounds each.
That's a lot of difference between the two measurements (211 vs. 69 inch pounds). I want hinges that will definitely hold, but they can't be so stiff that the mirror angle is difficult to adjust. I could use some help choosing the correct torque spec makes sense.
I would appreciate any advice or experience that you can share, regarding which brands and models of tension hinges to consider, as well as the proper torque spec necessary for the angled mirror adjustments.
Mirror Dimensions: 12 5/8 x 66 1/2 inches
Weight estimates:
Weight of 3/4 inch plywood backing, at 2.3 lb/sq.ft. = 13.4 pounds
Weight of 1/4 inch mirror: 17.5 pounds
Weight of primer, mastic, mirror supports, etc. = 1 pound
Total weight = 32 pounds
Torque formula = Weight x CG distance x cos(angle)
(Because the weight is distributed evenly, the center of gravity in this case is 1/2 the 12 5/8 inches length, which is 6.3 inches.
TORQUE CALCULATIONS:
* 0 degrees (mirror held in place horizontally, like a shelf, which may not make sense for this application, but is the MAXIMUM torque necessary):
32 pounds x 6.3 inches x cos(0 degrees) = ANSWER: 211 inch pounds of torque
Two hinges = 105.5 inch pounds each. Three hinges = 70 inch pounds each.
* 71 degrees (current mirror angle):
90 - 19 degrees mirror angle = 71 degrees.
32 pounds x 6.3 inches x cos(70 degrees) = ANSWER: 69 inch pounds of torque.
Two hinges = 34.5 inch pounds each. Three hinges = 23 inch pounds each.
That's a lot of difference between the two measurements (211 vs. 69 inch pounds). I want hinges that will definitely hold, but they can't be so stiff that the mirror angle is difficult to adjust. I could use some help choosing the correct torque spec makes sense.
I would appreciate any advice or experience that you can share, regarding which brands and models of tension hinges to consider, as well as the proper torque spec necessary for the angled mirror adjustments.
