The quotation Wordsmith gives about trunnels mentions their
use in covered bridges. In case you've never seen a covered
bridge, here's a photo of one:
http://www.virginiadot.org/infoservice/faq-covbridge.asp

:-) There's a Trunnel Elementary school here; I think it's named after a person, though. (And, it's made of brick, not wood!)

Dear Jackie: I found quite a few instances of "Trunnel" being a family name.
I wonder if any of them were "square pegs in a round hole".

I've got a piece of a trunnel from the recently restored Cilleyvile Bog Bridge sitting on my desk as we speak. And while I nevet met Milton Graton, the bridgewright mentioned in the Boston Globe quote, I have met his grandson (Arnold Jr.) who is admirably continuing the family business, along with several of his cousins.