I built my first three take-down recurves recently. Unfortunatly the scribe mark on one side of my new binghams jig was 3/64's off center. Pretty lousy craftmanship if you ask me. The drill holes were accurate. To continue useing the jig for my 2nd bow,what I did was to make equal thickness shims to place on either side of the the riser or limbs prior to clamping and drilling. This centers the jig more accurately than useing the scribe marks even if the jig was properly made because there's nothing to line up. Some day I'll make my own jig from aluminum and drill bushings. BTW, some types of aluminum can be machined with woodworking tools if a lubricant is used. John