Boring is Boring

Boring is Boring

For the ScopeRoller business, I often have to enlarge the interior diameter of a hole in a piece of Delrin to a particular, fairly precise size. I rough out the hole with a Forstner bit a bit smaller than the intended size, then use a boring tool to finish it to the required size, +- .002". Most of the time, the diameter that I need is just a few hundredths of an inch larger than the diameter of one of my Forstner bits, so one or two passes with the boring tool is sufficient.

Today, I'm making a set of ScopeRollers for the Celestron NexStar Super Heavy Duty mount, which requires a 2.400" bore. I have a 2.125" Forstner bit that fits into the chuck that mounts in the tailstock of the lathe, so it was easy to make a very accurately centered hole.

I also have a 2.375" Forstner bit, but it requires a 1/2" chuck--and there isn't one made that I can find that fits into the tailstock of the Sherline lathe. I can do it in the drill press, but the resulting hole isn't quite so precisely centered.

Anyway, the result is that to enlarge from 2.125" to 2.400" takes a number of passes. And it gets very boring. It occurred to me while doing this that "boring" (in the sense of being uninteresting and tedious) had its origin in the boring of cannon, which is a similar and much slower process. This online etymology dictionary seems to confirm that:

O.E. borian "to bore," from bor "auger," from P.Gmc. *boron, from PIE base *bhor-/*bhr- "to cut with a sharp point" (cf. Gk. pharao "I plow," L. forare "to bore, pierce," O.C.E. barjo "to strike, fight," Alb. brime "hole"). The meaning "diameter of a tube" is first recorded 1572; hence fig. slang full bore (1936) "at maximum speed," from notion of unchoked carburetor on an engine. Sense of "be tiresome or dull" first attested 1768, a vogue word c.1780-81, possibly a figurative extension of "to move forward slowly and steadily."

There is nothing that describes the process of boring better than "to move forward slowly and steadily." I suppose that I should try to find a 2.375" or 2.25" Forstner bit with a 3/8" shank, so that my boring is less boring.