Thanks for your kind response!
I still use the collet that I made for turning cribbage pegs. For those who prefer to purchase collets, I have found two tool catalogs that sell "collet reducers" for router chucks, they can be gotten in 1/4" OD and 1/2" OD. The 1/4" OD has only I/8 " ID and 3/16" ID sizes available and the 1/2" OD has the same ID sizes plus 4 additional IDs up to 3/8." Prices in 2019 catalog is are $6.99 US per collet, regardless of size. These are available from EagleAmerica.com, 1-800-872-2577.
Infinity Cutting Tools has same type collets in their catalog, but they show only 3 choices of ID, only in the 1/2" OD size: INFINITY TOOLS>COM, (877) 872-2487. My catalog from Infinity Tools is older, so I don't have current pricing for them. Best to check the web for current pricing from either source.
Even though these are labeled as "collets for router chucks," I am confident they can work in an ordinary drill, or lathe, chuck just like the improvised one that I made, but you will have to check the collet's position in the chuck each time you tighten the chuck jaws to ensure that the slots in the collet are roughly centered BETWEEN the jaw faces of the chuck. This isn't a problem in router chucks because of the different construction of router chucks.
Happy modelling to all!
Just a quick note to let you know that I received 4 collet-reducers for my recent birthday. Attached is a photo of them along with a few router bits from my Dremel Tool set. Two of the new collets have 1/8" ID which accepts nearly all of Dremel's cutters, burrs etc. These will enable me to use various Dremel cutters in my router.
My wife purchased the collets fro Eagle America, but there is at least one other catalog/internet source as well.