Options for aluminum spinners of any kind are rather thin right now. What size spinner and what are you using the model for, Perky Speed? You may have to piece something together like a vintage Froom or Veco unit with a custom nut with a machined shoulder as already mentioned. What are the threads on the shaft? Keep you eyes peeled on eBay for any spinner adapters that pop up, or even check with Tru-Turn to see if they have any stock on hand that they are still selling. Some of these Tru-Turn and Great Planes spinners have the prop driver section that is thicker than I think in necessary, and it can be turned thinner and re-knurled. I have done that on occasion.
Type at you later,
Dan McEntee