RE: Metal Frame Work Bench
My workbench / building table has a steel lower frame. It was purchased from a complany named Global Industrial and the cost was not too bad. The top is a 1 1/2" piece of maple, built like a butcher block, and sealed wtih some very durable finish from the factory. This was purchased from Woodcraft. Because the wood is made of many different pieces of wood it is very warp resistant and dead flat. It is really heavy but by adding wheels I can easily move it about. The wheels lock in caster and roll so there is no shake on the table when the wheels are locked.
The plane on top of the table has a 105" wing which was built on the table in two halves.
Choose the wood top first then choose the base to match.
When building I put a piece of drywall on top of the table to give me a pinning surface. Drywall, like the maple table, is dead flat.
SunDevilPilot