In this case, “U” represents a “Rack Unit” or “RU”, which has been for some time the standard unit of height for rack-mountable equipment. One RU has a height of 1.75 inches. Pretty much all rack-mountable equipment of which I am aware have heights that are integer multiples of 1.75 inches.
DaveD Sent from a small flat thingy > On Jun 11, 2019, at 02:02, Perry Sandeen via time-nuts > <time-nuts@lists.febo.com> wrote: > > Yo Bubba Dudes!, > Needing to go vertical with my test equipment I went bottom feeding for an > equipment cabinet on ebay. > To make a long search story short: they were way too expensive, too heavy to > ship and too far away for pickup. > So I kept searching and finally came across what was listed as *42U Four Post > Open Frame Server Data Rack 19 inches. Adjustable depth 23 to 32 inches.ebay > number 152319524877.Sold by Raising Electronics for US $188 and free shipping. > I was unsure what a *U* height meant put it seemed tall enough so I bought > one. > I was a little apprehensive about this being a Chinese metal product. I was > very pleasantly proven very wrong. > Although it only comes with a picture of an assembled unit it has been engine > ed so there is no way you can assemble improperly. The four posts are all > equal and can be installed with any end up or down and the top and bottom > brackets will fit. It comes with the exact 50 M6-20 head bolts and nuts > needed for assembly. The nearest SAE equivalent bolt size is 1/4 20 x 1/2L > which I purchased to hold L shelf brackets to the frame. > I set the depth of mine to 26 inches so my 5370's fit well and I had space > for both power and BNC cables to be inside the frame. > > This rack is designed to be bolted to the floor. Wanting to be able to move > it, I cut a piece of 3/4 inch plywood a little longer and wider then the base > footprint and installed 4 inch tall Harbor Freight swivel casters on the four > corners for ease of movement in any direction, even on floor carpeting. > After assembly it was 6 ft 9 inches tall. > > Now this being a bolted together *skeleton frame* it is prone to twisting and > or becoming a parallelogram sideways. To prevent twisting, I fitted a > plywood board on the top bolted to the top front and rear angle pieces. To > prevent a side-to-side movement required an 8 inch wide piece of scrap > aluminum plate bolted to the rear vertical posts. This is easy to do as > there are a plethora of precision spaced holes available. > There was some very serious thought given to the vertical post design. It > has six 90 degree folds done in such a way that the inner edge on each outer > side gives a 19 inch opening. > However behind it is as inner fold where one can install recessed L shaped > brackets. Now the inner fold is about and inch narrower than the outside > edge.This allows making a wider shelf that can *float* on top the brackets > but can't slide out either end. > This was very useful when configuring the instrument arrangement. > I also found that with the bottom shelf being just 6 inches above the floor I > was able to install more equipment in the same vertical space than in my > previous normal sized equipment cabinet. > Another bonus with this type of configuration is that it's easier to keep the > equipment cool and it's much lighter. > Regards, > Perrier > > > > > _______________________________________________ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. _______________________________________________ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
