Definition of "tinwork"

The most obvious part on a tractor is the tinwork – the nose cone, bonnet and wings: they are out there for all to see. If these parts look shabby, the rest of the tractor will look just like any other tractor, but get the tinwork right and your tractor will impress, and stand head and shoulders above everybody else's in the line-up.

2017, Richard Lofting, Vintage and Classic Tractor Restoration, page 228