The abacus has been around for centuries as a counting tool. It has mainly been used in the East, Russia and Europe. It is versatile as you can add, subtract, multiply and divide numbers on base 10 (normal counting), 16 (for counting ounces and pounds), 20 (as the Mayans did). For more information, follow the link:
https://en.m.wikipedia.org/wiki/Abacus

The great advantage of the abacus is that the user acquires a great ability to perform calculations with great speed. As a college professor, I am always looking into new ways to interest my students and make them learn much more than just the class topic. This semester I am showing them how to use an abacus and I decided to built my own. You can easily find them online but there is a special feeling of completing your own abacus.

ABACUS SELECTION

As I am a new user of the abacus and can still only add and subtract, I decided to built the simpler version. That is the Japanese Abacus named Soroban with 4 beads in the lower part and 1 bead in the top part. Nevertheless, the technique can easily be modified for the Chinese abacus, Suaban, with 5 beads in the lower section and 2 beads in the top… or even the “Mayan version” with 4 beads in the lower part and 3 beads on the top as they calculate on a basis of 20.

Step 1: Materials and Tools Needed

In a hobby shop I bought
• Beads (to make a 13 row abacus I needed 65 beads)
• Shish kabob sticks that would fit into te beads (one stick per row so I used 13)
• A piece of balsa wood 36”x3”x ¼”
• Crazy glue
• Sand paper

Tools
• Xacto knife
• Aluminum ruler
• Pencil to mark the wood
• Small hand saw
• Drill with bit the size of the shish kabob sticks

Step 2: Determining the Size of Your Abacus

Measure my beads to determine the size of my abacus. Leave a little room between the beads so they move freely. In my case, the 13 rows of beads required 10" space as I was leaving 1/2" additional space at each end

Step 3: Drilling Holes for the Sticks

Using a metal ruler and the Xacto knife I prepare a balsa plank 36”x ¾”x ¼” and cut 3 pieces 10” long. Leaving ½” on each end I marked the location of the 13 holes. Set the planks on the board and drilled the 13 holes on the 3 pieces at once

Step 4: Inserting the Beads for the Lower Section of the Abacus

Insert the shish kabob sticks and slide 4 beads into each one and insert the second plank that will be the divider between the top and bottom section of the abacus. I advise to use shorter sticks as the long ones tend to bend and even break when sliding the second piece of balsa.

Step 5: Finishing the Top Section

Slide the last bead in each stick and put the third piece of balsa on top. Slide all pieces to the size you desire. I used a gap equivalent to the height of 2 beads for both sections (top and bottom). Depending on your frame and bead sizes, it may be better to use a space equivalent to 1 bead.

Step 6: Gluing the Sticks to the Balsa

Be sure to have all 3 pieces of balsa perfectly parallel and aligned. Use a drop of glue to set each stick within the pieces of balsa being careful to have the beads away while doing it. Then cut the extra Length of the sticks as close as you can. It does not matter I there is some left as you will sand it later.

Step 7: Finishing It Up

The last steps to finish your abacus are:
• Using ¾” width balsa turned out to be too thick for the center piece. Sliding the top bead is difficult so I suggest using a divider the same size of the beads.
• You can dye it and decorate it as you wish to make it truly personal.

I AM SURE YOU WILL FIND THE ABACUS EXTREMELY INTERESTING!
It is fascinating to use and you can find how to use it following this link:
http://m.wikihow.com/Use-an-Abacus

Step 8: Final Remarks

• Using ¾” width balsa turned out to be too thick for the center piece. Sliding the top bead is difficult so I suggest using a divider the same size of the beads.
• You can dye it and decorate it as you wish to make it truly personal. Just be careful to protect the beads so they slide free.