Archery Business: Jul/Aug 2010
July/August 2010 archeryBUSINESS 31 which way to move the cam when the bow is dis-assembled. Generally, .010 inches of axle space equals 1\0378 inch of cam lean, as does one twist of the yoke cable. Next, with the bow at full draw, he again checks the cam lean top and bottom, and records the measurements away or toward the cable guard. "If you're going to compromise on cam lean, it will be at static rest," Villa said. "Ideally, you want zero cam lean at full draw. That's most critical. When the arrow gets thrust forward on release, if there's any left and right movement, your arrow's going to turn to a piece of spaghetti. It's not so bad if it just gives a little \036ick one way or another at the end of the power stroke because the arrow is already going straight." Next, he checks the cam synchronization. After drawing the bow to where it's hitting the end of the draw-stop module, he slowly pulls it back and forth while watching to see which cam touches \035rst and by how much. He checks the distance between the cable and the gap with a protractor and measures the degrees. If the top cam is ahead by 10 degrees, he will make a note and later see if he can correct for it with cable twists. Obviously, if it's a single-cam bow, he would have gone straight to the next step: cam tim- ing. Most manufacturers put timing marks for the number of holes on the cams. If not, Villa might call the manufacturer and ask for its tim- ing marks. Experience has taught him which manufacturers prove helpful and which ones not so much. Single-cam bows, if not properly timed, will have nock travel up and down during the power stroke. He can usually check this at static rest. If his careful measurements show the cam is out of timing, he notes what needs to be done later when he rotates it forward or backward until it's correctly positioned. During the next step, he checks for any con-tact involving cables and strings, either between each other or with a cam or limb. Again, after the bow is taken apart and reassembled, his notes will remind him to correct such problems. "Our goal is to get rid of all cable and string contact," Villa said. "If you don't, you'll always be deal- ing with wear, and the customer will go through more strings. It won't be cost-ef\035cient for him in the long run. String manufacturers recommend one twist for every four inches of string or cable length. You'll have issues if there is one twist for every half inch. Too many twists is not good, but you also don't want a dead string where there is no twist." Before taking the bow apart, he also checks its centershot alignment with the string's nock point. Bows are engineered so the arrow's center height should intersect the center of the hole for the Berger button, where the arrow rest attaches to the bow. The arrow should not rest above or below the hole's center. To check this, Villa locks a laser into the center hole and uses its side-to- side adjustments to line up the light beam so it splits the string. The string's nock-set loop should be 1\03716 inch above this intersection, to a maximum of 1\0378 inch above it, over a 12-inch spread using the customer's arrow. "The arrow rest itself does not change, so you want to make sure the arrow remains in the right place," Villa said.BREAKING IT DOWNAfter Villa has identi\035ed the bow's visible trouble spots, it's time to press the bow, remove the strings and cables, and bring it all the way down. He checks the axle spacers top and bottom while looking for any sign of axle \036oat or cam \036oat. "We shouldn't be able to move the axle or the cam back and forth," said Rink, one of Villa's technicians. "Everything must be snug. If you can move it 10 or 20 thousandths, you have cam \036oat or axle \036oat." Villa said the clearance between an axle bush-ing and the limb on the axle is usually 1 to 3 thou- sandths of an inch (.001 to .003 inches), with a maximum of .005. "You won't get that precise by feel alone," Villa said. "We use a taper-leaf gauge for measuring to 1 thousandth of an inch. It also measures hole diameters so we can tell if they're worn or elongated. You'll get axle \036oat if there are insuf\035cient axle spacers between the limb and the e-clips. You'll get cam \036oat if there are in- suf\035cient axle spacers between the cam and the limb. If you have too much slop in there, it leads to limb-cracking." Again, Villa records all this information on the spec sheet. "We write down not only how many axle spacers we added, but also their size, how many we shifted, and what direction we moved them. Customers need to know why they're pay- ing for four or \035ve axle spacers. We show them where we added two to the top, or why we added two and shifted one. We want them to visually inspect what we've done." Villa jokes that Tao's Archery Services might be the world's leading consumer of axle spacers. "I can honestly say we're the largest purchaser of axle spacers in Canada," he said. "And we're probably in the top 2 percent in the United States. We buy them in 500 lots." He said it's possible to produce a tight cam, but that he cannot add too many axle spacers. "When you put it under load you're dealing with a mini- mum of 60 pounds of pre-load, so it's not going to make any difference," he said. "More importantly, you need lubrication in there. As long as you have lubrication, everything moves correctly." While the bow is apart, Villa checks for loose limb-pocket screws, even if the bow is new. "I'd say 75 percent of limb-pocket screws are loose when the bow arrives brand-new, and that's across the spectrum of bow manufacturers," he said. "If you sell that bow and the customer comes back complaining about it creaking the \035rst time he draws it each day, check the limb- pocket screws. The creak often goes away after the \035rst arrow, but then shows up the next day the \035rst time he draws. If that's when he draws on a deer, he won't be happy." Villa said new bows are susceptible to loose limb-pocket screws because they're baked at 180 to 280 degrees to seal and harden their dipped \035nishes. "At those temperatures, aluminum com- ponents expand," he said. "When they cool and contract, the screws can torque. We tighten them, record how far we turned them, and then use Wite-out to lock them into place. If you ever want to loosen them, Wite-out breaks easily enough." Unlike many shop owners who believe tuning bows where customers can watch can lead to serious delays and other distractions, longtime pro shop owner, seminar speaker, and expert bow tuner Len Marsh likes to tune his customers' bows where they can see him worka move he says builds lasting rapport and credibility. 026-034_AB10JUL-tuningtips.indd 31 6/8/10 10:15:36 AM
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