I'm on a wild goose chase for Marie (don't ask) that requires me to drill a hole just a tad under 1 11/16" to hold a steel post. This hole will be through several pieces of 2x stock and a piece of 4x stock (it will be over 6" deep when done). Anyway, I want a forstner to drill the hole and (of course) don't have one. Worse, it seems there isn't one made in that size. I tried a few approaches drilling a 1.5" hole and trying to enlarge it (with a rabbet bit, and then flush trim) and I could get the hole to fit right...my attempts were either too large or too small. I had decide to get a 1 3/4" bit and just live with the hole being too large. This morning I happened to think, what if metric bits came in a proper size. I measured the pipe with my calipers set to "metric" and got 42.8xxx mm. Then searching for a 43mm bit I found one. Man, I love metrics.

If the hole is a little too large just mix up a little epoxy and put in in the hole before the post goes in. It will probably out last the steel post. 

Or cut a pop can and make a shim.

I will often switch to metric when I'm faced with a problem like dividing 11 13/16" into thirds.  It's much easier to divide 300mm into thirds.

 Years ago i got a calculator that expresses in standard, metric and fractions. I often have to get it out and think for me

Somewhere in the stacks of unpacked tools is a tape that measures in tenths of an inch. And, another that shows inches on one edge and MMs on the other.  Also, somewhere is a calculator that calculates inches and mms in fractions. But, I don't think there's anything but imperial sized bits among my tools. Well, some are wire sizes but those are still imperial, right? 

Edited July 12, 20215 yr by Gene Howe