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A Kids Bow

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vtsteam:
My daughter recently had a birthday and she'd asked for an archery set. Friends of the family bought her a kid's bow of fiberglass and plastic. It's kind of tough for her to pull back, and not very nice looking, but archery something we can do together, so I dusted off my old wood bow from the 70's and ordered a string for it.

I was thinking about maybe making a bow for her. Never done that before, but after a bunch of online reading I decided to start with a simple board bow for myself to get practice. I hunted up some wood I'd cut a long time ago on the bandsaw mill, and found a not too promising stack of hardwood that had fallen over in the woods. Most of the wood was wet and gray, though it felt solid with the fingernail test.

At first i was thinking of making it out of cherry, but that's apparently a pretty iffy wood for bows. Ash is considered good but it rots quickly and the ash boards didn't look good. I knew I had some black (sweet) birch in the pile, and these boards seemed sound. A quick check of wood properties online showed black birch has a very good set of specs better in fact than some of the more commonly used board bow woods. I'm not surprised as hard birch plywood is used in aircraft construction. I couldn't find anything online about black birch specifically for bow building. Perfect! Always like experiments with materials.

I ripped one of my boards into 1 by 3 inch strips, and chose the best -- with almost perfectly straight grain, about 6' long. Unfortunately when I planed it, there was a grain interruption at about 54", and I decided to cut it off there. I started to shape it into a short bow.

vtsteam:
To make a bow you gradually thin down the limbs in a process called tillering. The bow is placed on a post with markings on it to indicate draw length, and you pull down on the bowstring with a scale, while observing the shape at gradually increasing draws. You scrape off material until the shape looks right  and you've also brought the bow's draw weight to what you want it to be, at your draw length.

I decided I wanted about a 40 pound bow, at my draw length of 29". This proved to be more difficult to achieve than I realized, being a beginner to bow making.

vtsteam:
I should mention, there was a delay of a couple weeks between when I planed the board and shaping and tillering the bow. The wood needed to dry, which it did gratifyingly quickly. It had air dried in the stack over the years (maybe 7 years), and the recent collapse hadn't really wet it through. By the time I started shaping the bow, it was at 8% moisture content just from standing indoors.

Anyway, during tillering, it quickly became apparent that I'd never get this bow to draw 29". It was just too short for that using this wood. I really need a longer bow. So I decided to go ahead and make a child's bow of it. If I ruined it, it would just be for practice. And if successful, I could give it to my daughter. She needed a bow of about 15 pounds draw weight and 21" draw length. That seemed more appropriate for a bow this size, and much more do-able.

After working on the tiller for a few days I finally got it to draw at 18-1/2 pounds at 21 inches. I had her do a test pull, but she still thought it was hard to draw. Incidentally at about this time I tested her plastic bow on the tiller and was surprised to find it drew 22 pounds, though the packaging was clearly marked 15.

Here is the wood bow initially tillered to 18-1/2 lbs at 21":

vtsteam:
I received some advice from more experienced bowyers that the shape wasn't ideal, but that since it was still drawing over weight, I could probably correct it and reduce the draw weight at the same time. In the photo above you can see that most of the bend is near the center of the bow, and the ends are doing little of the bending.

It took another couple of days to carefully reduce the thickness of the taper to the ends, scraping a little at a time, re-stringing, exercising the bow by drawing it 30 times, and then checking the draw weigh and shape at 21"

Here's what it looked like at 16 pounds draw weight, when I decided to quit while I was ahead. Black birch is so stiff that the ends were getting very thin in order to make them flex more, and I just didn't feel comfortable going any farther.

But at its present state it pulls very smoothly, with no feeling of strain at 21" (I've pulled to 22" just for safe measure). The curve (or "tiller") is better and more of the bow is working. I tried it in its unfinished state, and shot 30 arrows into a hay bale, and was surprised at the penetrating power -- it buried the fletching on several aroows. And surprised at its accuracy, too. In fact i was having more fun shooting this small bow, I think, than my old Fred Bear recurve!

It still isn't finished, but I think it's going to work out well. I hope to shoot several hundred arrows after finishing to make sure it is safe and doesn't take too much set in the process, before handing it over. I'll post pics when that's done.

tom osselton:
Nice job!

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