What is the best practice? The fly points on many loudspeakers are countersunk holes (typically 10 mm or 3/8 in.) which are filled by flat-head bolts when not in use. The manufacturers recommend shoulder eye-bolts for flying. Shoulder eye-bolts are designed with the intent that the shoulder bottoms against a flat surface. The ideal piece of hardware in this situation, it seems to me, would be a conical washer that has the included angle of the countersink. To my dismay, McMaster doesn't have these, so they are unlikely to exist So what to do?
With no washer the jagged edge of the shoulder gouges into the tapered side of the countersunk hole in the plywood, which is ugly and will wear out the hole with repeated insertions. Should one use a (hardened, grade 8) flat washer? I appreciate your guidance.
(And, yes, my eye-bolts are the expensive ones rated for overhead lifting.)
--Frank
With no washer the jagged edge of the shoulder gouges into the tapered side of the countersunk hole in the plywood, which is ugly and will wear out the hole with repeated insertions. Should one use a (hardened, grade 8) flat washer? I appreciate your guidance.
(And, yes, my eye-bolts are the expensive ones rated for overhead lifting.)
--Frank