Warco Lathe Imperial Conversion

John Pace cuts imperial gears on a metric lathe.

When I bought my Warco lathe the only real thing I disliked was the machine was metric, as all of my other machines are imperial it was something that I had to live with. It has never been much of a problem as all the machines that I have are fitted with digital readouts so converting from one system to another is only a push of a button. When it comes to making something like a leadscrew the machine has similar problems to most other machines in that the conversion is near but not perfect. I have to say this Warco machine is able to make a 10 tpi leadscrew about 10 inches long with slightly less than 0.002 inch error.

This Warco machine has a system of change wheels and feed gearbox to be able to make a fair range of metric and imperial threads and dp and module worms. Some time ago the machine was converted to part cnc operation and was seen in an article in MEW 207 to 212.The addition of the cnc system has increased capability of the machine for most machining operations and has increased the ability of the machine to be able to machine threads and worms by milling. The electronic connection between two axis means that compromises and errors can be eliminated that exist between the spindle and leadscrew by a purely mechanical connection.

A time arrived where I needed to be able to make a 1/10 inch pitch leadscrew with as little error as possible. The usual route for this has a 127 gear in the train between the spindle and the leadscrew. I have such a set for my Myford . This 0.8 module set was made for me by Richard Bartlett.

The 0.8 module gears can be fitted within the standard gear change cover, the 127/60 pair used in conjunction with the standard change wheels allow a full range of error free metric threads.

More of a problem than I thought.