Hi Richard, thank you for confirming the diameter/thread pitch! I have found some on eBay, but they are metric. I will look into couplers. I was concerned they would add wobble, but I'm sure I can sort that out.
I'm glad I could bring back old memories! You're speakers are a key part of my bedtime ritual every day, thank you so much for your, and your team's, great work!
That is actually what I have been doing. You can see the block of wood I used to the left of the frame. My concern was that the block will "float" on the carpet, and not punch through to the wood floor to make a s