Got this to replace the chuck that came with my lathe and or mill. It runs true, 1/2 to 1 thousands out, I'm sue that the G1435 arbor I got with it helps in its accuracy. I guess I lucked out and got a good arbor and chuck combo. I have a Jacobs chuck as well that's my be older than I am I found it with my Father-in-laws old Sears lathe, lucked out again when my new lathe also had a M2 tail stock. I like the fit and finish of the South Bend better than the Jacobs. The only issue that I have or should I call it a feature because it doesn't have anything to do with the operation of the chuck, is that I like to store the chuck key in the chuck. Most have round handles but not this one it has flats on two sides. The remedy is to use a the key I already have and store the new one in the top of the tool box for a backup. I won't take from the ratting just because of the chuck key, that's a personal preference and not a flaw.