Store-bought eccentric and multi-axis chucks are expensive. I've never used one, but I understand that they work well and are easy and precise to use. My cobbled messes work to a degree, but commercial chucks are probably much more useful and convenient for changing eccentricity or shifting axes in measured steps, plus being able to return to any one step. BUT, some cost more than a quality mini-lathe!
My eccentric chucks are nothing more than a machinist faceplate with a radial slot for a dog. I used a shortened pipe tap moved along the slot to hold the blank and vary it's eccentricity. I can drill an accurate hole in a blank for a tap much easier than I can turn an accurate tenon for a die, but either a hole for a tap or a tenon for a die allows for _cutting threads. Much better for securing wood than the crushed threads made with a bolt or the headstock spindle. I also used a tailstock center or a rotating backing plate when possible.
I've sharpened and ridged the jaws of an independent 4 jaw wood chuck. Adjusts and holds pretty well for eccentrics. I've also slit a 2.5 in. length of 2 in. pipe into 4 sections and inserted them into the 4 jaw chuck as deep 'jaws'. I can round the end of a blank and move it off the spindle axis and hold it there in these 'jaws' or in a scroll chuck with deep jaws. Adjustments are limited and a pain to make. As for precision, forget it. It's true, "You can't go home again" nor can you go back to a previous axis with this set up. :)
I've thought about scribing concentric lines on a face plate and drilling holes on the lines , but scattered about the radii so they don't overlap. A screw or small tap could be attached to the various holes for holding the blank on different eccentric axes. Seems like a lot of messing about with imprecise adjustments.
Sorry for my tedious and confusing description. Do any of you have (or can suggest) other cheap homeshop chucks or methods for holding a blank on variable axes with convenient and fairly precise adjustments. If so, how do those of you bereft of pricey factory chucks do it?
Turn to Safety, Arch Fortiter