Let me introduce you to another workshop tool I use regularly.
To me, it is, a shop essential when building projects outside of toy making and for toy making also.
We are all quite aware of the problems that exist when using stock materials such as MDF, Particle Board, Plywood and various types of natural woods and mixing these board types on one project.
The biggest culprit is Plywood, we know and have experienced/discovered that the 3/4" plywood is not 3/4” and is indeed 23/32” and similarly 1/2” plywood is not 1/2" but is 15/32”.
It may not sound or look like a big difference, but when making cabinets, the difference between using a 3/4" router bit and a 23/32” router bit for joinery is a big deal.
But let us not worry about that right now.
There is a shop tool that can help you … it is a calculator, but not a common calculator, it is one that can accept entering measurements in fractions, fractions as small as 1/64” of an inch. It is quite versatile allowing you to perform all common mathematical functions and more.
Here it is.
It is called a ‘ProjectCalc - Calculator” made by ‘Calculated Industries’.
When it was first released to the market place it was rather pricey and has come down in price to an affordable cost, around $24.00 CDN, and can be found for even less on EBay and some local shops.
Displayed above is the basic version on the left and the more advanced on the right.
As you can see, it is not only focused on doing simple woodworking calculations but supports other common calculations for a home handyman also. If you wish to learn more about what it can do, I would suggest that you go to their website and download the instructional manual pdf file.
Let us get back to toy making and examples of where it shows its strength.
Problem 1 – How long to cut an Axle Pin or dowel for proper wheel attachment.
I have drilled a 3/4" deep hole in a board to accept a common Axle Pin.
My wheel thickness is 1/2" and I would like to have a 1/64” space between the wheel and the board it is to be secured to for freewheeling of the wheel.
How long does the tenon of the Axle pin need to be?
Let us work out the math using the basic ProjectCalc and I will show you the screen shots of the display.
Enter the value 1/2” for the wheel thickness as per their calculator’s instructions.
Then press the ‘+’ key.
Now, enter the value of 1/64”, for the freewheeling space.
Then press the ‘+’ key.
You will see the results of both of the entered values, being 33/64”.
Now enter the value of 3/4", for the depth of the hole made for the axle pin tenon.
And complete the calculation by pressing the ‘=’ key.
Here are you results.
The length of your axle pin tenon should be 1-17/64” supporting your dimensions.
OK, I have a feeling of what you are thinking … that is a pretty high level of accuracy just for attaching a wheel.
I agree with you 100%, and in practicality, the tenon can be cut shorter and still work and if you used a 1/64” spacer between the wheel and the surface of the wood it is being mounted to there will be no problems inserting a shorter tenon into the glued hole and end up with a freewheeling wheel.
My purpose here was to demonstrate the calculating capabilities of the tool, presenting to you that measurements as low as 1/64” can be entered and calculated.
Let us do something a little more down to earth and repeatedly done while toy making.
Problem 2 – Do I have enough wood for this project?
I have a piece of wood which is 2 feet, 3-3/4” in length or 27-3/4".
My project needs cut pieces of 7-5/8” in length.
How many project pieces can I cut from the length of wood I have in hand?
Enter 2 feet, 3 and 3/4”, which represents the length of wood you have in hand.
Then press the ‘÷’ key.
Here I am demonstrating entering dimensions using feet and inches, you do not have to convert to inches before you do your additional calculations.
Enter 7 and 5/8”, the length of the wood you need, and want to know how many you can get from your wood in hand.
Lastly press the ‘=‘ key for your results.
You can cut 3.6 pieces of 7-5/8” from the wood at hand.
Notice the display is not in inches or feet, that is not what you asked for.
You asked for how many pieces of a specific length you could get, that is why it gave you a whole number and it decimal equivalent.
How much wood is left over?
Using the calculator again enter 7-5/8” multiply that by 3 and you will get 22-7/8”.
Now clear the screen and enter 2 feet 3-3/4” (or 27-3/4”) and subtract 22-7/8” and you will see the remaining piece of wood is 4-7/8”.
Ah … but it is not … you did not compensate for the thickness of your saw blade, which we will say is 1/8” and the three cuts required to make the three pieces.
So from the calculated 4-7/8” you would subtract 3/8” (1/8 x 3 cuts) which leaves you with 4-1/2”.
That math is only necessary if you really need to know how much wood is scrap because of a secondary piece part requirement for the project.
It may have been easier to calculate this if you added the width of the saw blade, 1/8”, to the length of the piece part you wanted, 7-5/8”, which would be 7-3/4”.
Multiply that by 3 to yield 23-1/4” and then subtract that form the board length at hand being 27-3/4” you will end up with the same result being 4-1/2”.
I hope I have not really confused you with the math, but believe me, using the calculator for simple or complex mathematics is really simple and no scratch pad, eraser and pencil is required.
With today’s technologies and ‘apps’ available I know you can buy an ‘app’ for your phone that does the same thing and software to load onto your computer if you wish.
This calculator is much easier to carry around in the workshop, in the garage or helping a friend build a deck at his house.
Take a look at it and see what you think.
Remember, at some point in the near future, someone is going to ask you – what do you want for your birthday, Father’s or Mother’s Day, or even anniversary.
Be prepared have the answer or get another shirt and tie.
Happy Toy Making