For those making wagons, buggies, carts, sleighs, etc., consider the reprinted (or original, if you can find them) Sears Roebuck and Montgomery Ward catalogs. They are a treasure trove of detailed drawings of vehicles, harness, and hardware (buggy steps, springs, lanterns, harness parts, etc.)

Sears Roebuck 1894, 1897, and 1908 along with Montgomery Ward 1895 seem to be easy to find as reprints.

For example: http://4.bp.blogspot.com/-AU2BA-0JDp...OOK+-+1912.jpg