Kinder Shop is the name I call my woodworking program for four year olds at the local daycare. This is a good age for them to have an abacus so this is our project. This is an American Schoolroom 10 bead school abacus. This one is designed to be used by young people with little or no fine motor skills and are prone to drop things. It has top and bottom rails, left and right styles, three wooden dowels, and 30 hardwood toy wheel used has beads. All pieces are hardware to make it sturdy and costs less than $5.00 to build. It is a great project for an adult (at any woodworking level) to do with a favorite kid. It is also a great project for birthday parties or youth activity groups. It is all finished with Howards Butcher block conditioner.
This is a very child safe finish and when parent ask me about safety I squirt some in my mouth. That ends their concerns. I have designed this as a kit an adult would build and the kids would assemble. Older kids could cut and assemble the whole thing.
Step 1: Top and Bottom Rails
Before you buy wood you need to decide if the corner joints will be butt joints or rabbet joints. Google this if you don't know what they are. The attached photo shows that my construction is rabbet joints. I like the look and it is a bit stronger. The disadvantage it takes tools to cut them. The butt joints only require simple cuts and these can be done for you at you local home center. In either case you will need about 2-1/2ft of 1x2 (3/4in by 1-1/2in). This is available at you home center. In either case each rail is 9in long.
Step 2: Left and Right Styles
The style will be 4in long for butt joint construction and 4-3/4in for rabbit joint construction. Each will need three 13/64in dia. holes 1/4in deep. One is in the center while the other two are 1-1/4in above and below the center hole.
Step 3: Dowels
Take a 3/16in dowel and cut three pieces 7-15/16in long.
Lightly bevel the ends and finish with the butcher block conditioner.
Step 4: Wheel Markers
The markers are made from 30 hardwood toy wheels 1in diameter and 1/2in thick.
You may be able to find the wheel locally. Since I am designing projrcts for kids, I use a lot of wheels so I buy them 500 it a time. Take 15 of them and cover with brown (black, red, whatever) shoe polish. Then finish with the butcher block conditioner. The kit is now ready for assembly.
Step 5: Glue and Nail Rails to One Style
Take the rails and glue & nail them to one of the styles. (The other is used to hold the top rail in place.) For rabbet construction you will need 1in finish nails. For butt construction you will need 2in finish nails. It wouldn't hurt to drill pilot holes before hammering in the nails.
Step 6: Install Dowels and Wheels
Stand the abacus on its side, insert the three dowels, and on each dowel place 10 wheels. The pattern used here is five light followed by five dark. Other patterns are available.
Step 7: Glue and Nail Final Style Into Place
Place the remaining style onto the dowels. Check to see the dowels are not too long to keep the style from fitting into place. (Shorten them if too long). Apply glue and nail into place.
Step 8: Sand
Sand the abacus to take care of any gaps or mismatches. Start with 80 grit and move to 120 grit.
Step 9: Finish
Use the butcher block conditioner to seal the unfinished rails and styles. Buff with a rag and it is ready to use.
Step 10: Alternative Bead Patterns
We used the traditional placement shown in the upper left as it easily shows the five mark. The one in the upper right used a different color only for the fifth and tenth beads. The one in the lower left has only a single color beads which may look nice but makes it hard to quickly read the number of beads. (Humans can only identify about seven object at a glance. This is why social security, phone, and credit card numbers are broken up into chunks no larger than four.) My favorite is the lower right. For base 10, the tenth bead is redundant. It is helpful for young users to separate the carry and add into two processes. However it doesn't take long to learn to combine the steps. At this point the tenth bead becomes a nuisance. Beside I find the symmetry of 4-1-4 to be pleasing.
Step 11: The Shop
I thought I would show the KinderShop setup. We have six benches with 3in thick tops, sized for four year olds. Each station comes with a hammer, paint brush used as a broom, a shop rags and safety glasses (blue basket).
It all stores against the wall. You can see we have a miter box saw, a bucket of saws, a bucket of drills, and a bucket of rasps and other odds and ends. The saw bench goes home with me.