The sub rails on the cab of my 1930 coupe are rotted to the point the doors are sagging. Once I removed the passenger's side and inspected it. It appears it was made from multiple layers of 1/4 wood. I'm wondering if this is how they are made or should they be one solid piece of wood?
Both single piece and laminated main sills were factory. They used what ever "hardwood" type and dimensions they could get. I have never seen multiple layers of 1/4" thick pieces but have fairly often seen two or three pieces laminated to get the ~ 1 3/4" thickness most often needed.
I will let the wood body experts jump in on this. My understanding is that the wooden bodies used different types of hardwood. It is much strong than softwoods like pine. Most treated boards are pine.
It might not make much difference for the bottom of a door. I would hesitate to use pine for more structural portions of the body.
The wood of choice for most reproducers is White Ash. Originally a strong preservative was used to provide rot protection. Softwood like pine or other species that don't lose their leaves in the fall are not typically used in automobile bodies. Strength, resistance to changes in dimensions and susceptibility to rot are the reasons.
