Round 2: Layout and Glue-Up
We’re going to build a 68” pyramid bow with a target weight of 50#@26”/55#28”. It's called a pyramid because the limbs will be shaped like a pyramid when finished. This type of bow is efficient, easy to make from boards, and is VERY easy to tiller. In fact, sometimes they need little or no tillering after the bow is profiled to shape.
Your first task is mark the face with the straightest grain as “back.” This part will eventually face away from you when you shoot the bow and will need the straightest grain possible to maintain its structural integrity as it stretches in tension at full draw. Mark the other face as “belly.” This side will face you when you shoot the bow. Now, on the BELLY side, mark your stave as in the picture below. The section marked “Tip Overlay” is optional and will be described at a later date.
Still working on the belly side, find the vertical center of the 68” section and square a line across the board. Mark this with a “C” for center. Then, square a line at 3” and 5” from both sides of your centerline. I mark the 3” lines with extra dots so I can keep everything straight in my little pea brain. Your stave should now look like this picture (minus the green lines running horizontally along the stave, which we’ll get to shortly).
NOTE: As outlined later in this thread, I would now recommend an 8" riser section to give you more working limb and a better look. To accommodate the 8"riser, mark the center (C) as normal, then draw a line 2" and 4" from either side of it. The two lines 2" from center denote the end of the limbs' front profile fade (i.e. the "pyramid" shape) while the lines 4" from center indicate where the ends of the 8" riser block will be. All other dimensions and procedures can remain the same. Now, mark the horizontal center of the stave on your center line. If using a 1”x4”, this mark will be at 1 ¾”. (Remember, the 1”x4” is really ¾”x3 ½”). Now, mark 1 ½” above and below this mark to give you a total of 3”. Now, do the same thing on the vertical lines located 3” to either side of your center line (the ones I marked with dots). Connect these two lines along these marks as in the picture above.
Now, at both ends of this 68” section, find the exact center of the board, which again will be 1 ¾” from either side assuming the board is true. (Check just to be sure!) Now, put a mark 1/4” to either of this mark, which will give you a 1/2" width overall at the tips. Next, connect these marks with the lines your drew between the dotted lines. Here’s a picture of what that’ll look like:
Now, here’s a picture of how to do it. Just clamp a straight edge along these two marks. These horizontal lines now represent the outline of your bow.
Now cut off the tip overlay and riser sections from the end of the board, leaving just the 68” section. Cut along these profile lines on this section using a band saw, jigsaw, or handsaw. Be sure to LEAVE YOUR MARK! You’ll trim it down to the line later. By the way, the bandsaw in the picture is a cheapie Delta benchtop model that does the trick. If you have a bigger model, great. If not, buy yourself a new 1/2 blade with about 7 teeth per inch and get your fingers out of the way!
Clean the mating surfaces of the riser block and bow belly with acetone (fingernail polish remover) to remove all the oils. This is kinda’ overkill, as red oak isn't that oily. But, it certainly doesn't hurt and is a force of habit for me.
Once the acetone is dry, spread a good layer of Titebond III on both surfaces, line the ends of the riser up with the lines marked “Future End of the Glue-On Riser,” and clamp it up. Please use Titebond III. It’s tough as nails, moisture resistant, and cheap. The kid at Menard’s might tell you Titebond II and Titebond III are the same thing, but he’d change his mind in a heartbeat after a broken bow relocates his nose while staring down a trophy buck in a drizzling rain!
The next part is optional. You can choose to add a glue-on recurved tips if you’d like, or you can just skip it and not worry about it. It’s a technique that Tim Baker wrote about in the TBB. If you’d like to try it, cut the tip overlays apart and clean them with acetone. Now, mark a line across the BACK of the bow 6” from the end of each tip. Clean this area with acetone and then put a few pieces of masking tape starting at the 6” mark as shown in the picture below.
This will prevent glue from getting all over the back of your bow. (You’ll be cutting off a good portion of the belly of the bow later, so you didn’t need to do this when gluing on the riser block.) Now lather some TBIII on both surfaces and clamp.
Then, let the whole shootin’ match dry overnight, as in the picture below:
That’s all for Round 2. Be back later for the next part!