What do I need to convert to metric?
After fumbling with fractions on a recent project, I'm ready to make the leap to the metric system. My planer and tablesaw have dual scales and I already own small metric rules and calipers. What challenges will I need to overcome to make the switch?
—Charles Jackson, Montgomery, Alabama
It sounds like you nearly have the tools covered, Charles. For those remaining stationary tools that aren't metric-ready, buy and apply metric- or dual-scale stick-on tapes. Benchtop and portable tools may still require a conversion calculation, but the blades and bits you already own are probably close enough to a metric standard to make little difference.
The rest depends on your woodworking style. Do you design and build projects on the fly? If so, then you'll have few problems using metric through the entire process. The most difficult challenge will be your own long-ingrained sense of measurement: A ceiling is about 8' high, a desk is about 30" tall, but how high is that in centimeters?
On the other hand, if you're the type of woodworker who works from someone else's plans, you could be in for a lot of time with a calculator converting imperial to metric then double-checking part and sub-assembly dimensions to eliminate the possibility of cumulative errors. It might not be worth the hassle.
Of course you can avoid much of the hassle of conversion by using a method older than either system: Measure as little as possible. Instead use one part to mark another, building your project piece by piece.