12/1/2001

Someone mentioned QCR8 rack frame rigidity. I just did some tests on a stock QCR8 rack frame.

Test #1:
Using a machinists dial indicator good to .001" and a 5LB weight (size 34 stepper motor). AT THE CENTER of 1 bar with that weight applied the deflection is only .030" ( 30/1000th of an inch ) the thickness of 10 sheets of paper. That's just a single bar not both, it would have taken 10LBS of pressure to get that much deflection with both bars top and bottom. And that measurement is at the center which is worst case. And this is WITHOUT any modules added which adds 15% to the thickness. This amount of force is never applied to a panel during use, and if it was it would deflect very little.

Test #2:
I laid a box on the floor that has rack rails in it. Put the QCR8 on top AND STOOD AT THE CENTER without breaking or even bending the bars. I weigh 155LBS and ALL of my weight was on the center (gotta take a pic of that one!)

If you have a QCR8 that is flexing then you're plugging patch cables in with 200LBS of force or you have one of the very first rack frames which are made of 1/8" aluminum. Only a handful of these were sold.

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Roger Arrick - Synthesizers.com,
Proud designer of VERY STRONG rack frames (probably a bit over-designed actually).