This is a project done on my Sherline 5410 mill using TurboCnc 3.1a.
The photos below show various stages of the machining of the puzzle. It is simply a number of accurate boring jobs in a row.
Directions for using g-code file 3cubes.cnc to machine 3 nested cubes. (File: 3cubes.txt copyright Tom Hubin, 26 November 2004)
- Start with a 2 inch cube of 6061 aluminum. This can be a 2 inch length cut from 2 inch square bar stock.
- Mill or fly cut the outermost 1.950 inch cube from the 2 inch stock. Be sure to machine something from all six sides so that the finish is attractive.
- Label the six sides as top, bottom, right, left, front, rear.
- Drill 3/8 inch diameter center holes into top, front, and right surfaces to a depth of 1.5 inches. These three holes will pass completely through the innermost cube. I used the 3/8 inch end mill holder with a machine screw length 3/8 inch diameter drill bit.
- Drill 3/8 inch diameter center holes into bottom, rear, and left surfaces to a depth of 0.75 inches. These three holes will not touch the inside of innermost cube. That way the 3/8 inch diameter center holes through the innermost cube will be seamless.
- Secure the 1.950 inch cube in a vise and use an edge finder to accurately locate the rightmost surface and the rearmost surface so that the center of the topmost surface is at (X,Y)=(0,0).
- Load a 3/8 inch diameter x 5/8 inch LOC aluminum roughing end mill. Move it over the topmost surface. Lower the bit until it just touches the topmost surface. I usually do this by loosening the bit so that it drops down and touches the topmost surface. Then tighten the bit just enough so that it won’t fall out.
- Run the program. You will be prompted to touch the surface with the end mill. You have already done this so continue.
- The bit will be raised and you will be prompted to tighten the bit and start the spindle at 2800 RPM, which is max spindle speed on a Sherline mill. Tighten the bit securely then start the spindle.
- Stay near the machine, lubricating and clearing chips as machining takes place.
Here are the CNC files in various formats. Right click on a file to save it to your computer or open it with the appropriate program.
- 3CUBES.CPP (3cubes.cpp is a plain text Borland c program to generate the gcode file.)
- 3CUBES.CNC (3cubes.cnc is plain text gcode for TurboCnc 4.01.)
- 3cubes – all files (zip format)
(NOTE: If you cannot open these files, try downloading the ZIP file that contains all the original files. To do so, CLICK HERE.)
The remaining 3cubes.* files are binary files generated by the Borland C++ compiler but are not needed.
*.txt, *.cnc, and *.cpp are plain text files and can be read and modified with just about any DOS, Linux, or Windows text editor. DOS Edit command can be used. I use the shareware DOS text editor PcWrite. Microsoft Notepad, WordPad and Word are Windows text editors that can be used.
Here are some websites to help visualize the nested cubes:
- http://www.dakeng.com/gallery.html—Dan Statman’s dime sized nested cubes. Small and very very classy.
- http://www.grapevineglassworks.com/landscapes/cube.html—Artwork showing nested cubes with no hole through the center.
- http://www.geocities.com/barxe/cubering.swf—Animation showing something similar but here just for fun.
- http://www.token.crwoodturner.com/magiccube/—Shows inner cubes detached so as to tumble freely within outer cubes.
This article first appeared on the Sherline CNC Projects Page.