Metal Burr Puzzle




About: I am an engineer and I like to build things. I am well versed in drafting and solid modeling and enjoy a nice challenging build.

Puzzles are fun. I enjoy the endorphins that are released by successfully solving a puzzle. This one is a tough one that I made. The design is a simple 6 piece burr puzzle, machined out of 1/2" square steel stock. Credit for the design goes to Bruce at ''.


Step 1: Materials and Tools

The items you will need are:

  • 1' of 1/2" square steel stock (15$) cut into 6 equal chunks
  • 1/2" endmill
  • Milling machine with vice
  • File for deburring edges
  • Plans (does not have to be the ones provided here)
  • Safety Glasses for the mill (last thing you want is a big hot metal chip flying into your eye ball sizzling and boiling your eye juice)
In terms of time, this should only take 2 hours at the most if you know how to use a milling machine. If you don't know how to use a mill I suggest you learn. It is fun making metal chips.

Step 2: Milling the Bars

Of the 6 pieces you only need to machine 5 of them. I set up my work by doing a single pass at 1/4" depth for each required cut using the 1/2" diameter endmill; when doing a big depth cut like this, make sure your using coolant on your tool to keep it nice and sharp. Since I don't have a fancy digital readout on the mill I use I set my vice up with a stop so I could cut each piece in the same location as the previous one.

The first operation is to cut 5 pieces right down the center as seen in the second picture. When this is through, 1 of the five pieces is now done, set it aside with the unmachined piece.

The second operation is to cut the 4 pieces left as seen in the third picture. This is where the stop comes in handy, each cut will be in the same location on each piece as long as all six pieces were cut to the same size. Refer to the plans on the dimensions of the cut. With this operation complete, 3 of the 6 pieces are now complete, set 1 of the 4 aside.

The third and final operation is to cut the remaining 3 pieces as shown in the fourth image according to the plans. It is important to note that each piece should be set up the same as the previous one to ensure locational accuracy and consistency. When these cuts are complete the easy part is over. All six pieces are now to size.

The next part is a little more difficult or at least more tedious. File down all the burrs on the edge and file down all the cut faces to ensure that they fit on each other and can slide freely upon one another. This took me about an hour to get them all to fit nicely.

Step 3: Completion

Once it was all made and all the pieces could fit together, it was time to assemble it. Unfortunately I underestimated the difficulty of this little guy. Without looking at the solution it took me about a week to put it together correctly. It works great as a nice little paper weight also. Does not have to be made of metal, could easily be done as a wood shop project too.



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5 Discussions


Question 3 months ago on Step 3

please help my students and i are stumped we need a solution.


2 years ago



2 years ago

Dude, you're like, AWESOME!!!