With regards to my previous post, I just tried and a D-Way 3/8" gouge will not fit in a 3/8" Carter & Son wood turning adapter. It is most likely true for 1/4", 1/2" and 5/8" also.
I have a SB Tools Carbon Fiber ER25 Collet Handle and a Carter & Son 1/2" gouge will not grip before the collet or nut bottoms out. The ER collets supplied with the SB handles are 1/32" over the nominal size. To use the Carter and Son gouge in the SB handle, I would have to change from a 17/32" to a 1/2" collet. I don't know what the collet size is that Robust supplies with their ER collet adapters or handles. The C&S gouges that I have generally run 0.003 - 0.004 undersize. The raw steel stock size runs 10 -15 thousands oversize. D-Way tools are not finished down to a nominal size. Doug Thompson turns his gouge shank size to the nominal size. He will supply gouges in the raw steel size to fit the Glaser handles for use with epoxy. If you want to use the ER collet type handles across multiple tool manufacturers, you may have to change collets also, for example 1/2" to 17/32" to accommodate "1/2 inch" tools.