For many musicians working with the Cycle of Forths and Fifths is very important, whether for chord practice, music composition, improvisation. I have looked all over the place for something practical that I can use for my studies, so I made this one.
Since I have gotten so many great ideas from this site I thought giving back a little would be nice.

Hope any one out there finds it useful!

Cheers

Step 1:

Basic drawing materials.
Compass, rulers,
2 Foam board 20" x 30" x 3/16" (I chose yellow with white back.
one: 2" x 1/8" Screw with 5 nuts
Five: 1/6" washers

Step 2:

Make a couple of big circles. In the space between them I will later put the Keys in order of 4ths and 5ths

Step 3: Drawings

In order to keep the balance and for lineal reference I made to perpendicular lines across the inner circle.

Step 4: Keys

Since the cycle of fifth has 12 keys I dived the inner space between the two circles in 30 degree shapes

Step 5: Naming the Keys

Some people put the cycles in contrary order that I did. That's how I learned them. Either way the order is always the same. With a letter ruler and a marker I wrote each key in the order of 4ths

Step 6: Cut Off

Later I cut the cycle off. At this point you may notice that I darkened the lines with a marker and my compass.

Step 7:

On the other board then I replicated the 12 shapes. The Idea is that on this 12 shapes I can fill the common information for the key that will be sitting on that position every time I work on a different key. For Ex. degrees ii, vi, scale, etc

As you can notice the ruler messed up the lines a little, so you want to consider what to draw those lines with.

Step 8:

With envelop labels I wrote the information for each of the 12 shapes on the second board. In my opinion what you wish to write will depend very much on what you want to work with. For me I indicated the Degree, function of each degree, applicable scale, applicable arpegio to play against chord. You can also indicate key signature, relative minor, etc. The idea of the labels is that I can update information just by adding a label without having to make the second board all over again.

Step 9: Bolts and Nuts

in order to put the first circle on the second board and make it rotate as a roulette I
- put a washer on the back of Second board
- One washer on the from and 2 nuts on the front. The idea of the 2 nuts is that you lock one against each other and that will prevent the nuts from rotating with the first board. (Cycle)
- Put a washer on top of the 2 nuts
- insert the first board (Cycle)
- put another washer on top of the Cycle
- put 2 more nuts to lock the space between the washers holding the Cycle
- tight slightly leaving enough room for the cycle to rotate, but not loose

Step 10: Voila!

And you're all set. If you're interested on learning how to practice with the Cycle of 4ths and 5ths there are many good videos on youtube.com and plenty of information on the web. Or you may want to visit a good harmony professor.

Good luck!