Internal LH Thread Cutting

[Parlo]

The tool you showed will cut left and right hand threads running the spindle CCW . Your feed direction would determine a left vs a right hand thread . The opposite hand bar is for running the spindle in CW rotation . It will also cut left or right hand threads once again depending on your feed direction .

The tool shown is a right hand & will only cut internal threads running in the usual direction, often referred to as forward. For left hand threads the spindle stays forwards to suit the tool with the leadscrew direction reversed. To clarify the spindle rotation in the quote, it is CCW looking from the tailstock end.

 

[bumbino]

The tool shown is a right hand & will only cut internal threads running in the usual direction, often referred to as forward. For left hand threads the spindle stays forwards to suit the tool with the leadscrew direction reversed. To clarify the spindle rotation in the quote, it is CCW looking from the tailstock end.

Thanks for clarifying the viewing direction. I'll make a mental note of that.

I did forge a cutting tool for internal threads in the coal forge yesterday. It came out great! I'm still now 100% sure of the material, but it's from a machine shop. just a little under 1/4 round stock. Formed the tool and quenched in canola oil at 150°. Hard enough I can't cut it with my best files. After sharpening it cuts aluminum and it cuts steel conduit pipe. Very nice tool. Very rewarding experience and saved around $70!!

Best,
John