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5C collet blocks will get a lot of use. Note that the set usually doesn't come with a pin wrench for tightening the nut, so order one with it. They do come with a cam-operated nut, but I found this generally useless. Of course you also need a set of collets to use with the blocks.
My 5C set includes imperial sizes by 16ths. Largest size is 1-3/16". Largest size that stock can go completely through is 15/16". Of course they make metric sizes as well as square and hex collets. I have bought a couple of these special collets over time, such as a couple of square sizes. These are mainly for use on the lathe where I have a collet chuck.It's not a good idea to vary stock size by more than +/- a couple of thou from the nominal size of a collet.