We have an incomplete set of collets at the museum, some of which had seen better days. I selected the poorest ones and put packing in the slots and bored them with my 6mm solid carbide Garant with Garant inserts. The inserts are like hens teeth and I had to pay the full price for original ones, but they are worth it. I bored collets to 5/16" , 3/8" , 1/2" and 5/8", plus 8, 10, 12 and 16mm. Using smaller Picco solid carbide boring tools, I also did 1/4" and 6mm. Despite the interrupted cuts and hard surfaces, the bores are pretty good and stock sizes run true better than 0.0001" tir.
I also have some of the external ring and cone stepped collets plus the opener / closers. There is one of the NOS cone collets on ebay for a reasonable price, unfortunately, it is identical to the other one I bought some time ago from the same vendor, or I would have snapped it up.
I would think trying an auction price starting at £9 each if selling individually, but some odd sizes will not be likely to sell. Or £7 each starting if they are sold in bundles, which would be more likely to get rid of them. I hardly ever use them, so I would not be interested.
Edited By old mart on 13/01/2020 14:10:29