At work we used to say, “measure with a laser, mark with a crayon, cut with an ax.Recently I was able to install the 1-1/2" d-ring tie downs which will permit me to secure my ZARGES K470 aluminum cases with a 2" x 8' cam buckle strap. For fasteners I opted to use two inch long 3/8" x 16 carriage bolts plus one washer and one nut. I came close to purchasing 1-1/2" long ones but am glad I went with the 2" ones - see why below.
All measurements were taken using a digital linear caliper fresh from being calibrated at a metrology laboratory and accurate within 0.01 mm (or 0.0005"). Actually, this is all I had available since most all of the measurements I take are very precise. A Class I tape ruler or tape measure would have been fine but this was the closest.
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All precision measurements were immediately transferred to a very precise marking system comprised of masking tape on top of carpet. This is when you should laugh.
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Here is an installed d-ring tie down. If I remember correctly each tie-down when properly installed is good for a one ton load so securing my ZARGES K470s using two tie-downs should be fine.
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The challenging part of this installation was the fact that the tie-down straddled a vertical wall underneath and my goal was to place one carriage bolt on each side of the invisible vertical wall. I took my time, checked my measurements, rechecked everything again, and then drilled my holes. Here is a bolt on the "inside" of the wall.
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Here is a bolt on the "outside" of the wall. Now you can see why I was fortunate to have selected the 2" bolts - if I had not I would have run out of room here. I felt the thickness of the material while drilling the outboard holes and was unaware it was thicker in this area. Despite my limited experience with this type of operation things turned out acceptable.
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Complete system: ZARGES K470, d-ring tie down, and 2" cam buckle strap.
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