Hi everyone
Some years ago I acquired a (circa 1957) Colchester Student roundhead 6" lathe, it needed some work and still does, when I get an idle hour I pull the sheet off and do a bit...Last week I had another look at the screwcutting side of things, when initially tested some while back it cut a really fine thread whatever was selected..last week I found the sacrificial shear pin was broken at the headstock driver gear and when replaced things seemed sorted ...I was pleased until I realised that the lathe is cutting apparently double the TPI that is selected... ie select 6tpi it cuts 12tpi....the changegears are 21t/ 120t/ 35t which according to the manual I found on line are correct...I stood and stared at it feeling I am missing something basic and would welcome any ideas........
Stuart
Some years ago I acquired a (circa 1957) Colchester Student roundhead 6" lathe, it needed some work and still does, when I get an idle hour I pull the sheet off and do a bit...Last week I had another look at the screwcutting side of things, when initially tested some while back it cut a really fine thread whatever was selected..last week I found the sacrificial shear pin was broken at the headstock driver gear and when replaced things seemed sorted ...I was pleased until I realised that the lathe is cutting apparently double the TPI that is selected... ie select 6tpi it cuts 12tpi....the changegears are 21t/ 120t/ 35t which according to the manual I found on line are correct...I stood and stared at it feeling I am missing something basic and would welcome any ideas........
Stuart