I have just got out of hospital and am not allowed to do any heavy work , I have had this indexing head for thirty years it came with four disks 24,30,36 and 42 divisions , as I make clocks this wasn't enough so I made an attachment for dividing a 30 to 1 worm from a burnt out motor but it has backlash , I decided to improve it needed a new worm to fit my 20dp change gears so I set the lath up before the opp to just turn handles and push buttons .