We are Cougar Robotics and this is for the Instructables Sponsorship Program.
One of the things that our team has made routine is what we call double drilling our Tetrix channel. We repeat the standard hole pattern where it isnt to give us more mounting options and general mounting flexibility. We have found that it doesn't weaken the channel in to a noticeable factor. The bottom piece in this picture is what the channel started out and the top shows the holes we added. It all matches the same pattern, to keep modularity and reusability.
Step 1: Supplies
Everything you need comes in the Tetrix Kit except for the tools.
1. a piece of channel to double drill
2. a Tetrix flat plate
3. two screws and nuts
1. Drill (preferably a drill press)
2. 9/64 drill bit
3. alan key to tighten screws
Step 2: Set Up Jig
Screw the plate onto the channel so that the hole patterns of the two are offset by 32 mm. Make sure that the screw holes that do line up line up well, your pattern is based off of this.
Step 3: Drill!
Now all you have to do is drill all the holes that are in the plate but not the channel. We have found that you don't need to do the entire circle pattern, only the + pattern. We double drill all of our channel before we put it on the robot. This way, we are never disassembling the robot to add holes (or at least less often).
We have found that it is usually only necessary to drill the holes into a + shape, rather than the full "flower pattern."