MicroRAX is a mini-slotted aluminum building/prototyping material, similar in concept to 80/20 and MakerBeam. Extruded aluminum beams are formed with an X shaped cross section and bolted together using nuts and other fasteners that fit into the slots. This sort of T-Slot is common in machine shop tools and other fixtures. It is a great way to quickly build a frame without having to custom cut and drill parts.
I was putting in an order to Sparkfun and decided to add a MicroRAX Medium Kit to build some frames. Shipping on my order was already expensive (once over $100 it HAS to go UPS, which is roughly $50 to Maui), so I figured adding in the microRAX would be offset the expense. The box arrived yesterday and today I got a chance to play with it.
There isnt a lot of documentation on how to use it – none provided in the kit. MicroRAX just recently (late 2011) opened up a MicroRAX Wiki which may build up more info over time. Their YouTube channel has a few decent videos. They have an ok overview and another on how to do joint assembly – and some other treats…
Basically you join the beams together using a cover plate, a nut plate and several M3x5mm screws. The kit came with three different types of cover plates – L, Corner and Truss. There are two ways to put these together. The videosays to screw the nut plate to the joining plate and then insert into the beam….
This works ok sometimes. However I found that the nut plates can be difficult to get into the slots. Perhaps its a tolerance issue, perhaps its some flashing left over from the press cutting of the nut plates. When dealing with multiple corners, it can be REALLY hard to maneuver the assembly to get the nut plate to line up right. This is especially pronounced when dealing with something like a box. You only have so much freedom of movement and its nearly impossible to get all the plates slotted up before pushing it together.
So the alternative is to put the nut plate into the slot first and then line up and screw the joining plate onto it. Pretty easy.
I decided to try building up a quick box using a few of the parts in the kit. It didnt take very long and brought back memories of playing with Erector Sets. One trick is noting the direction the L-Joining plates will go, and being sure you are putting the nut plate on to match properly. I had to flip over one to learn this. There is another video showing how to make a linear slider with just the basic parts, so I added one to the box to give it a try. Pretty easy if not elegant.
It should be fairly easy to put MDF or Acrylic sides on a box like this. It wont be water proof but it is a nice quick way to make a small frame. For larger projects I would definitely use 80/20. The MicroRAX folks recommend it for projects over 18 inches.
Here’s a flickr set from my first night building….