Oct 10 2011

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Big Curve, Little Curve

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My son’s preschool teaches writing with a system called Handwriting Without Tears. It is a much simpler character set to learn and can be represented by four simple shapes: big curve, little curve, big line, and little line. You can buy sets of wooden lines and curves to practice making letters, but the sets I found for sale were thin plywood and not very good looking. I decided that I could do better.

Some more information about the letters:

  • The big line measures 10″ long by 1″ wide.
  • The little line measures 5″ long by 1″ wide.
  • The outside radius of the big curve is 5″ and the inside radius is 4″.
  • The outside radius of the little curve is 2.5″ and the inside radius is 1.75″.

I laid out a big curve on on some 1/2″ thick maple¬† that was 6″ wide. Then I cut out the curve on my scroll saw. I’m not very steady on the scroll saw so I ended up smoothing out the inside and outside radius quite a bit on my oscillating sander. I decided that it would be easier to use a circle cutting jig on my colt router than to cut out any more curves this way.

I had previously made an offset base for the Colt router, all I needed to do was create a slot in the base for an adjustable pivot point. I did this with a 1/8″ straight bit and moved the fence a few times to accommodate the bolt I was using as a pivot. My first cut went well, I set the distance between the center of the pivot and the inside of the bit to 5″, but when I went to make the second cut, I set the 4″ distance between the center of the pivot and the inside of the bit again. Being a 1/4″ bit, it left only a 3/4″ wide arc. I should have set the distance to the outside of the bit!

Once I realized my mistake I was able to cut out 3 more big curves and the outside of 5 small curves. I couldn’t make the inside cut with the router because I couldn’t set the pivot close enough to the bit. So I had to use the scroll saw to cut the inside curve. Using the router to make the cuts, meant that I didn’t have to do much shaping of the curves on the oscillating sander, I just needed to knock down the ridges caused by making multiple passes with the router.

Making the lines was much easier, I just ripped 1″ strips of 1/2″ maple and cut them to length on the miter saw. Once I had all the pieces cut out I relieved all the edges with a 1/16″ round over bit.

After machining the pieces I noticed that one of the big lines had a defect — it looked like maybe the plane used to surface the board ripped out a chunk of material. To fill the void I mixed some of the maple sawdust with wood glue until I got something the consistency of peanut butter then overfilled the hole. After the mixture dried I sanded it flush. In hindsight, the patch was a little too dark, I probably should have used white glue, but I didn’t have any on hand.

I sanded all the pieces with 100 grit and then 150 grit. I know I should have gone to an even finer grit as I could see scratch marks in the wood, but I already had way to much time sunk into this simple project. I coated the pieces with three coats of wipe on urethane, sanding with #0000 steel wool between coats, and rubbed the finish down with a cotton cloth after the last coat. 

All said I made 10 big lines, 10 little lines, 4 big curves, and 5 little curves. Even though I put in way to much time and effort to make the letter parts, the result has been worth it — my son Isaac has been already played with the set for many hours in the last few days.

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