Alberti Bow Butt Drill Fixture
This Bow Butt Drilling Fixture is a super accurate way to place the frog screw hole in new bows and is excellent for boring and re-drilling bow handles for restoration. Because of the extremely tight tolerances of manufacture of the tool and drills—and the locating of the fixture on the underslide mounting surfaces of the bow—the drilled screw hole will be perfectly aligned with the axis of the underslide. Centering of the drill bushings can be done with the concave locating tool that places the starting point of the hole in the center of the end of the bow handle. Or if working with an unfinished stick, the hole starting point can be established with the pointed locator. Either way, the hole will be parallel to the underslide.
This tool and system of drilling exceeds in accuracy and utility any other tool or method of placing the screw hole, and step drills are also provided for the 2.1mm diameter screw nose hole. Our Bow Butt Drilling Fixtures have been in service in a few of the world’s best restoration shops, and it has been reported back to us that even when boring with the largest sizes of drills there has been no break-out of the handles. But the multiple drill and bushing sizes allow for drilling in steps to remove as much or as little wood as you would like. Removing the bow from the fixture and replacing it back will not affect the alignment, but the bow might also be left in the fixture when bushing the hole by removing the drill bushing end plate and then quickly realigning with the centering tool.
Provided with the tool are:
- 7 drill bushings sized 3.1mm, 3.3mm, 4mm, 4.5mm, 5mm, 5.5mm, and 6mm
- 9 drills sized 3.1mm, 3.3mm, 4mm, 4.5mm, 5mm, 5.5mm, 6mm, 3.1X2.1mm and 3.3X2.1mm
- 1 locating tool with two concave ends, for violin/viola and cello/bass.
- 1 locating tool with a center point end.
- Two clamping cauls.
Bass bow screw drills will be available sometime in the future.