[Arran]

Hmmm...that had not occurred to me. Good point. Well, I'll be more careful from now on in looking for true 1/4" round metal stock for shaft extensions.

You almost have to take one of those 1/4" shaft couplings along to make sure the size is correct. You just can't trust sizes anymore with almost everything being imported. The other day I went to buy some 1/2" plywood at Lowe's. They only sell 15/32" so I had to change many of the finished sizes in my plans

If that was cabinet plywood the convention in N.A is to quote the nominal dimension not the actual, so it was 1/2'' before being sanded down to 15/32''. If you want full dimensional plywood you need to either use construction grade or Baltic Birch, not sure about that pine ply imported from Chile though. Most radio cabinets used a full 1/4'' to 3/8'', hardwood plywood, often poplar core by sometimes maple or ash.
With regards to rod for control shafts I picked up some fiberglass rod at the dollar store, they are sold as driveway markers so they are bright orange with reflective stickers wrapped around them. The reason I needed them is I have a pair of Hallicrafters S-38s with broken tuning control shafts, the original shafts were made out of a grey fiber substance since the S-38 is an AC/DC set with a steel cabinet. I have to see if they are the proper diameter, but even if they are not they only cost $1 each.
Regards
Arran