Window crank extensions

I have a 1932 five window coupe. The guy before me had cut the window crankshafts down. Now, of course, they rub on the upholstery. Unfortunately I did not catch this during the build or I would have welded on extensions as I have done in the past.

Does anyone know of a vendor where I could purchase an extension for old Ford 3/8 shafts? It's a fresh car so I am trying to avoid making my own, and possibly doing damage welding and grinding on the car.

Thanks

 

I have a 32 3 Window Coupe with
No spline on the window regulator shaft. Mine has a flat on both sides of the shaft that the crank attaches with a screw.
Is there an extension to extend this type of shaft?