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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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3 comments

  1. Jeff

    Nice letters and I can appreciate the even radius of the curves. Do you often fix defects with glue and sawdust? I need to fix a small problem with my current project and had considered doing something similar, but was not sure of the results.

    Jeff

    1. benjamen

      Thanks,

      About the glue and sawdust:

      This was my second time trying the sawdust and glue technique, the first was my box joint box. It’s a trick I’ve seen used on a lot of woodworking sites. The thought is that it will match the color of the existing wood.

      My patch was a little darker than I would have liked, but that wasn’t as important as filling the hole and preventing splinters in young hands. For color matching, I think white glue would work much better.

      The consistency was also a little grainy — it was hard to work and get to stay in place. Next time I try I’m going to use sawdust collected from sanding at 220 or higher grit rather than the mixed 100 and 150 grit sawdust I used. Maybe instead of a peanut butter consistency, I’ll shoot for pudding. I’m also wondering if adding a little bit of water would make it more workable, or if it would swell the wood and make the patch contract when it dried.

      If you’re going to use it on something you really care about, I’d definitely experiment on some scraps or a lesser project.

  2. Jeff

    I am using Charles Neil’s pre-stain conditioner on my project which, as I understand it, is basically watered down white glue. I was thinking about that with some 220 saw dust. I may try it on a scrap and see how it works.

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