I have a SHOPTASK 1720XMTC that I bought back in the mid 1990's, mounted onto a bench and have barely turned it on in all these years. I am just now starting to use it for some things and am basically familiar with some machining methods, but am no machinist, so I have a basic question.
One of the products I work on is a spool valve that is often rust pitted and needs to be ground down to smoothly slide in a rubber seal. The area in question is .50" diameter and can only be turned down .020" max and still seal, so I turn it as little as I can to get a smooth finish, usually les than .010".
Actually, it is hard to turn this hardened steel item with a bit, so I grind it down with a tool post grinder - leaves the surface much smoother and cleaner than I can get with a bit. I currently do this on a little 9x10 mini-lathe and clamp the outer area of the spool (.875" diameter) in a self-centering 3-jaw chuck. Of course, this is not well centered for grinding, but works out well for the accuracy needed for my work.
I would like to grind these down on my Shoptask and do a more accurate job. Am I correct that the part would be better centered if it was secured in a collet as opposed to a self-centering 3-jaw chuck? What style of collets will work in my Shoptask and what is needed to adapt them to my lathe spindle?