The only cheap solution I think of wood be to mount a cheap cross slide vise on a wood lathe. I have one i got from harbor freight that would work. Don’t know how long the dowels need to be, but this should work for pieces 6 inches and under, otherwise the deflection on the workpiece will make holding tolerance real difficult
After looking at this a minute, something else pops up. The sizes and tolerance are the same. So if you make a slightly fat 24/32 you have the 24 and 25. Sand a little for the 23, same for the 27. i kind of doubt that this is what your customer has in mind. Probably they are looking for size +/- 1/64.
@HerbStoops - They are using them for ring sizers to make and fire ceramic rings. Each ring size is slightly different. She needs 4 or 5 in each size IIRC.See RING SIZE - Carrera Casting no finish its the size that matters. But they need to be accurate enough to tell the difference between the sizes and they cant vary along the length
@Nikonbill - Yes that is what they are looking for. If we tried for half sizes then we would need to go down to 1/64th but in wood that’s sort of getting crazy. A damp day would vary the sizes by more than that I suspect Yeah I thought of making some vice jig but again its a lot of work for a small job.
I’ve told them to find someone with a machinist vice and it will be a simple job.
I assume this would be for displaying the different size rings.
Or is this to cast or form the rings. Wood is in my opinion not right to form the rings. Maybe some metal rod would work too, short pieces could be chucked in a drill motor and filed while the stock rotates.
That one video showed the long rod for sizing,with steps of sizes from small to larger.
Anyway it is out and beyond me, if they have the dowels already then chuck them in a drill press and sand them down to size.