May 14, 2019

Thread cutting LoGan manual lathe

Thread cutting on the manual lathe need not be scary. While production threading of parts is rarly done on a manual lathe these days, Having the skills to set up and cut threads on a manual lathe can be very usefull in a job, or prototype machine shop. Repair, or one of, a part, can somtimes be done signifcantly faster by a lathe hand proficiant in both internal and external threading operations. Manual lathes have either change gears, or a quick change gear box to set the ratio between spindle and lead screw that determine the tpi of the thread. Add a threading dial for locating the start of the thread and a half nut to engage tool feed and the engine lathe proceed to cut screw threads instead of the normaly expected smooth surface finish of conventional turning.
In this video I show a short example of how easy threading on a Logan 920 manual lathe can be following basic set up of the lathe. This internal thread cutting job is part of a spindle thread protector for the lathe it self. They do say a lathe makes it's own parts. Every part that this old logan makes for it self, is years added to its already long life. The thread being cut is 2.25x8 in cast iron to fit over the nose of the spindle when a chuck is not in place.
Thread cutting on the Lathe Simplified, Single Point threading no DRO, no threading stop, no flip up tool. Internal or external threads cut on the manual engine lathe, my way. How to cut threads, explained 60 degree threads and 29.5 degree compound angle explanation any one in the machine shop can understand. screw cutting