I needed to cut some left hand threads the other day. In fact, I mostly wanted to try it. The manual says to swap one of the 42t gears with the spacer on the other shaft. Sounds simple. Not so much! I found that when I moved the banjo to engage the gear the A gear hit the spacer in its new position, or the B or C gears hit the box containing the electronics, or some combination of both. A quick call to LMS and Chris solved my problems. He said to ignore the chart in the manual and the one stuck to the machine, and use this instead: http://littlemachineshop.com/reference/change_gears.php. Brilliant! Just wanted to pass that along.