The deeper I get into rod building the more I wonder why standard sizes aren't used. As an example, reel seats. I.d.'s .445 or o.d's .660. How come standard sizes such as .625 or .750 aren't used. It seems life would be easier for the builder.

Many components are actually sized by their manufacturers in millimeters and centimeters and once imported you're being given the English equivalent of the metric sizes.

Now this isn't always the case. Sometimes what you're seeing is the standard sizes spec'd by commercial rod manufacturers to fit the butts, etc., of their rod blanks. These same components are offered on the custom market and in the same sizes that were originally crafted for the commercial rod operations.

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Yes, when is US going metric? The rest of the world already heading that way. The longer it's left the costlier the conversion. Learning the imperial system and later needing to convert to metric only showed what a pita the imperial system was. As an adult you may be used to it but it's complicated for the children who have to learn it.

We went with the metric system for our monetary system, but unlikely to ever switch our system of measurement.

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It is really sad, that the US has not converted to the metric system.

The US was well on its way to converting to the metric system in the early 70s.

But the AARP or association of retired folks went before congress and claimed that their folks would not be able to make the change. Congress backed off and the change to the metric system was halted.

The metric system is just so simple to work with, and the US is one of the few remaining countries in the world that still uses the system.

For example, about 90% of all of the nuts and bolts today have been changed to metric. We just need to continue and get the job done.

Be safe

[en.wikipedia.org]