TBone:
1. Install the back plates on the boxes.
2. Install all radios into the boxes.
2. Adjust the boxes so the fronts of the RADIOS line up together.
3. Clamp them together but don't use much pressure or have someone hold them for you.
4. Wrap them in duct tape. You'll be amazed at how well this will hold them while you work on them.
5. Remove clamps.
6. Remove radios. Removing the backplates at this point is optional but it makes the next steps much easier with them removed.
7. Build up your mounting brackets. Once the angles/mounting brackets are drilled to the racks you can remove the tape and you will have a nicely aligned stack.
Some pics:
Taped together but the fronts are not aligned because the radio faceplates are slightly different thicknesses. I have a PMA-8000B on top of an SL-30, SL-40 and a GTX-327. The GTX and PMA were a bit different than the Garmins IIR.
Building the support angles. The Garmins are a bit wider, something like .05 (maybe they are narower, I can't remember). Some folks shim the smaller items, I chose to file the angles wider for the wider items and it worked great.
Front angle is installed. I removed most of the tape and left a single strip around the back while I made and installed a side angle bracket (not shown).
The final project. They came out nicely. I talked with 2 different avionics installers and both said no gaps were necessary between the units. The provided vents and dimples provide sufficient standoff.
The most difficult part of the whole process is finding a srewdriver to reach into the back of the boxes. It is a challenge to get a man's hand in the boxes and turn a driver.
![Smile :) :)](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
Tool shops will sell you 12 inch #1 philips but they are quite dear. I ended up using a phillips bit in a 12 inch 1/4 inch drive extension.
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