No math today thankyou…

From time to time, I teach young people woodworking in my shop, and one of my selling points is that I tell the parents that woodworking requires math. If the parent is wishy washy about letting their child take a class, I tell the parent about all the math skills we will be using, and that seems to clinch the deal. I think math is important, and although I am not very good at “high math,” I think it is really cool. Woodworking has really reinforced my skills with fractions, division, and doing math in my head, and if I don’t say so myself, I think I am pretty good it, but yesterday, I threw my ruler and calculator out the window with replaced it with an ancient tool; dividers.

A long time ago, my father gave me his K&E drafting tools from the 1950’s. I love and cherish them. They are high quality tools and they will have to be pried out of my cold dead hands (along with my father’s US Navy Dress Sword, and my #4 Lie-Nelsen smoothing plane) before I would ever give them up. Up until yesterday, I never used the dividers, but they proved to be solid gold when I needed them.

Here’s the situation; its 3rd and long, way back in our own territory….Opps! Wrong story. Okay, here’s the real deal. I am making a bed, and the head board and foot board have vertical slats. There are seven slats, the distance across is 39” and each slat is 2 13/16” wide. So how much space needs to between each slat? Go ahead, do the math. I’ll wait…………. Give up? It was really quite easy. First, find the middle of the bottom rail and mark it at 19.5”. Next, mark the middle of the middle slat and line up the maks. You know that there will be one slat in the very middle, and therefore three on each side of it. Now put one slat up against the post on the left side, then the right. That only leaves two slats to space out.




For the sake of this exercise, look at the right side of the foot board. Right now we only need to concern ourselves with one side of headboard since the other side is a mirror image. We have the distance between the right edge of the middle slat, and the left edge of the slat next to the right post. Eyeball what you think might be the correct distance with your dividers and align each space between the slats with the dividers. I got it right on the third try. As it turns out the correct space between each slat was 3.25”. I figured it out so quickly, that I had to do my happy dance. I had been dreading to the math, then the idea about the dividers came to mind and I jumped on it. I think dividers will become a more important tool for design work in the future. Yea baby, woodworking old school!

Open groove on the left





The upper rail and bottom rail each have a 1/2” deep, ¼” wide groove to receive the slat tenons. Between the tenons, there is a small piece of wood that fills in the gap. This was easy to do. I found some scrap on the floor that was about the right size. I planned it to the exact thickness, then used the table saw to rip the correct height of the strips. My saw bench hook and a stop block made easy work of cutting each piece to the precise length. Man oh man, it’s hard to beat a well executed plan!

Cutting the small fill pieces






Has old school technology saved you?



About yaakov

Husband, Abba, Furniture Maker, Turner, Bookseller, and all around working stiff.
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5 Responses to No math today thankyou…

  1. Robert says:

    You can find the middle of a line with a compass, which is simply a divider with lead at the end, or using a scribing divider if you don’t mind marring the surface. Simply set the distance to something obviously greater than half way and draw a portion of a circle using one end of the work as the center. Then flip the compass around using the other end of the work as the center for a new circle. Now Use a straight edge to draw a line between where the upper circle arcs cross and where the lower ones cross. That line will be at the center. Naturally you can further subdivide each side further using this.

    This is presumably done before the final planing which would remove the lines. I learned this back in grade school or high school…can’t remember exactly when.

  2. Lazy Larry says:

    I took technical drawing at high school 40 years ago, thinking I would never really use it… well I have had lots of times when I needed to draw a 3D representation of a project and I found that I could… don’t ask me how I remembered… It just came to me…unannounced…after all that time

  3. Bob says:

    Great story! I like it. I will need to teach my grand kids how to do it that way.

  4. yael says:

    What are the names of the tools in the picture you showed I’m curious. The 1 that looks like spider leg

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