Round 7: Checking Short String Tiller/Draw Weight, and Adding Nock Overlays
I like to add temporary nocks using a wooden wedge secured with masking tape to transition from the tillering string to the short string. NOTE: For a great tutorial on making a quality Flemish string and jig, visit the following site:
http://www3.sympatico.ca/ragiwarmbear/diy/flemish/flemish.html.
Make sure you wrap the temporary nock really well or it will want to slide down the limb on you. If that happens, you’ll change the tiller of the bow. I always place a mark on the back of the bow where I want the nock to rest so I can see if it’s moving or not.
I check the tiller on the tree using the short string, and it looks almost identical to the initial tiller check we did with the tillering string. Satisfied for now, I want to check my draw weight. I’ve learned two rules about tillering that have saved me a lot of time and headaches. 1) Never pull the bow further than it is tillered correctly, and 2) Never pull the bow past your intended draw weight. I will now go back and forth between the bow scale and tillering tree balancing these two rules as I seek to find what my draw weight is at 26”. If the tiller gets out of whack on the way there, I stop and retiller by scraping the stiff spots, pull the bow 30 times to give the wood time to settle, and then recheck the tiller. In the case of this bow, I don’t have to do any retillering and I find that the draw weight at 25” is 51# (or a projected 54#@26”). Perfect! But “WAIT”, you say. Didn’t I just break rule number 2 above? Kind of, but here’s a little trick. I don’t actually pull the bow to 26” just yet. I like to hit my target weight at 1” shy of the intended draw length. That gives me a few pounds to play with as I do the final shaping and sanding on the bow, and allows the wood to settle a little bit as I shoot it in.
Now, if you don’t have a bow scale, here’s a handy little setup I often use. I take a bathroom scale, a 36”-40” long dowel or square stick, and a small square scrap of plywood and make my own. I attached the stick upright to the plywood using screws. (In the one in the picture, I used a fortsner bit to countersink a hole to receive the end of the dowel. I then glued it and screwed it to the plywood) I make a notch in the top of the stick to hold the bowstring and then make marks on the stick at 24-31 inches from the top in one inch increments. These will tell me the draw length of the bow (I measure to the back of the handle. This is a whole other ball of wax, and you should familiarize yourself with how to accurately find YOUR drawlength, as well as how to measure drawlength a bow. Use the search function on this site.) When I place the string in the notch and pull down on the handle of the bow, the weight is transferred through the stick onto the bathroom scale. Simply read the poundage on the scale and VIOLA!
Now, if you want to get really accurate, you can make a fancy calibration system as shown in the following picture (ha ha!)
I simply set the gallon water jug on the scale and adjust it to 8.34 pounds, minus the weight of the stick. As stupid as it sounds, I weighed several custom wood/glass bows and they read dead on for their marked draw length using this method!
The next thing I want to do is add nock overlays. These allow you to cut a groove more deeply into the tip, which keeps the string in place better. They also can add a bit of decoration. I’m using coco bola, although you can use any dense hardwood, including osage. I true up one face of the nock overlay using sandpaper on a flat surface. These overlays are just about 1 1/4" long.
You then need to flatten the very end of the bow tips on the back side to accept the nock overlays. They must mate perfectly, so take your time. When you’ve got a good match between the overlay and the tip, clean the mating surfaces with acetone, especially if using a tropical hardwood. When dry, lather both surfaces with TB III and clamp it up. (If you don’t want to add nock overlays, just search this site for various pictures of bows [self bows in particular] that have more traditional nocks.) You'll notice that I butted masking tape up against the tip overlay. As I did before, I add this tape before the glue-up so that it doesn't smear all over the back of the bow.
Once dry, shape the tips to your satisfaction. Dutchwarbow has posted some really beautiful tips on his buid-alongs, so I encourage you to look at his designs. Here’s how mine turned out:
I use a small round file to rough cut the string grooves. I don’t cut all the way through the overlay, and I angle the grooves at about 45 degrees on the sides. When they’re fairly smooth I take and heat a roofing nail with a torch and burn the grooves smooth.
Okay, all we’ve gotta’ do now is finish shaping the handle, check the tiller while drawing the bow in the hand, add a stain (optional) and finish, install an arrow shelf (optional), and wrap the handle (optional). That’s an easy stretch to the end, and we’ll be done in no time! Take care, and thanks for following! See you next time.