Friday, October 21, 2011

Jacob's Ladder CNC Case Parts

  Over the past couple of days I have been cutting parts on my CNC machine.  The parts will be used to make a display case for a Jacob's ladder.  For those of you who do not know what this contraption is the best description I can give is this.  In a lot of the old time Sci-Fi movies there is always a laboratory with a mad scientist.  In this lab is a Jacob's ladder running.  It is two wires that form a "V" and a large electric spark moves up this "V" getting larger and larger and it looks very scientific.  My friend Steve Hamer at the QC Co-Lab maker space in Davenport Iowa built one of these devices. 

This is a Blender 3D image that I put together of the Jacob's ladder case. As in real life this devise is dangerous with the use of high voltage to make it work so a display case is  must.  The case would be approximately two feet tall or so.  Originally Steve and I thought that a plexiglass clear cylinder would be a great idea until I tried to find one online.  Great idea but EXPENSIVE! So I came up with this design.  The plastic for the cylinder is actually the center sections from two liter pop bottles.  The labels on the bottles can be easily removed and with a little WD-40 the glue cleans off nicely. 

These parts make up the base and outer rings of the display case and are cut from 3/4 inch pine.  I drew up the parts in my ProE design software and then did all the conversions that needed to be done in order for my CNC machine to understand what I wanted to make.  This involved modeling the parts in the computer, creating a STL (stereolithography) file, sending it to Mesh Cam software which takes the STL file and creates the G-Code for the CNC machine.  It sounds rather complicated but really it's just a matter of learning a bit of software and hitting the right buttons when needed.  After the rings were cut out on the CNC machine I sanded them smooth with a sanding drum on my drill press.   The CNC machine cutting bit leaves a rounded corner when you cut a slot so I cleaned up these up with a band saw in order to square them up for the outer support rails.

These three pieces are the outer support rails that hold the display case together.  These parts were a little to large to make on my CNC machine so I marked the wood up from a drawing I created on my computer and then cut all the parts out on my band saw.  It was actually faster this way and it all worked out very well.  As with the wooden rings and base parts these parts were also made from 3/4 inch pine and are 23 inches long with the widest portion of the supports only being one inch wide.   The notches in the parts will lock the rings and base in place when assembled.  With some good wood glue it will be plenty strong enough for this display case project.  I'll post more photos of the cylindrical case once Steve gets all the parts put together and painted.  Hopefully I'll even get a video of the mad scientist's Jacob's ladder running.  Just what we need for the QC Co-Lab.... something else scary looking and dangerous. What could be more fun to build? 

1 comment:

  1. Great work! I love the way you have present this so beautifully! keep writing!
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