I picked up a SX2 Mini mill recently via Little Machine Shop (They call it the HiTorque Mini Mill 3900). When I received it, I noticed there was a port for a digital tachometer readout on the side of it. I though this might be useful, but felt 125$+ for it was a little excessive for what it was. Atop of this, they were out of stock.

I ended up reverse engineering the protocol, building some less expensive kits, and documented how exactly I figured out the protocol. Along the way, I also discovered how to make the mill run in reverse!

If you wondered how a reverse-engineering problem like this is approached or what tools are used, this could be an interesting read:

http://macpod.net/misc/sx2_tachometer/sx2_tachometer.php

We hosted our first CNC/Makerbot User Group meeting. A special thanks goes out to Brian Dolge for organizing the event and making it a success. We had a great turnout with about 20+ people in attendance. Marty McGuire demonstrated his Makerbot by drawing on Post-Its with a Sharpie. Harford Hackerspace demonstrated their CNC Milling machine by cutting out a wooden Ninja star. Check out the images below.

We are currently in the process of revising our CNC design since the Y/Z axis was eating its rails over time due to slight alignment issues.  We decided to upgrade the bearings in general to avoid the problem in the future.  The x-axis seems to be working fine, so we are going to leave it alone for now.   The revision includes CNC cut pieces instead of hand cut pieces (using table saws and drill presses).   We also did a major upgrade to the bearings and went with ACME-type lead screws to minimize backlash and improve accuracy.  We updated the stepper couplings to the lead screws to make future maintenance easier.  The redesign is expected to be complete within the month.

This video is in response to the one posted here, where a Mr. Riley Porter moves a 35 pound dumbbell with his CNC.  We decided to try to trump his CNC’s weight-moving ability by pushing our machine to lift and move first 45, then 55 and finally 65 pounds!  We wanted to continue with the weight increases, but did not have a safe way to attach more weight to the Z-axis assembly.  Our CNC build is turning out to be quite the beast.  Now all it needs is a catchy name…

The CNC machine’s construction has advanced to the point where we can begin to cut items.  Being a bunch of teenagers trapped in adult bodies, someone decided that we should cut a throwing star from sheet aluminum.  One copy of CamBam and 6 minutes later and the star was ready to be cut!  After a few adjustments and a bit snapped in half from being dragged through the metal too fast, the cutting was underway.  The star took about 10 minutes to cut and was an excellent first attempt at metal production.  The next step is to use the CNC to cut more precise parts for itself and help bring about the Robot Armageddon.   Special thanks to our newest sponsor, CamBam, for supplying us with a free copy of their most excellent software.  Note: The soundtrack to this video may change at any time as we are experimenting with YouTube’s AudioSwap feature.

Tonight our CNC showed signs of life. We attached a pen and drew images of circuits, skulls, and Road Runner. The CNC Router was the first project we started working on and it has taken many nights of team work to get to this point. There is still a lot more to do. We started working on the Z-Axis tonight and once that is finished we will have to take most of the machine apart and make fine adjustments to make it as precise as possible. After that there is the long process of mastering the 3D Software.

[flashvideo file=video/SDC12936.flv /]

I know I’m bad with these photo updates. Mostly because I am having too much fun at the Hackerspace that I just forget to take photos. I took a lot more photos than these but it turns out that my flash card was bad and my camera never let me know. I’ll try to recover those images later.

So, last week we finished building the Y axis for our CNC project and we talked about launching a payload into near space. Before that we built a Corstarch Monster for Electronica Fest and we were messing with some PIC kits (microncontrollers) using speakers and LCDs as outputs. Now that I have a new phone which actually takes decent photos (the above were taken with my Palm Pre) I will probably be able to share more of our hackerspace with those of you who don’t like to leave your computer chair.