Drummond M Lathe Extension

摘要

Photograph 1 shows the completed project extending the bed of a Drummond M lathe in order to machine shafts that are up to 5ft long between centres and up to 11/2 inches in diameter. Screw cutting is a requirement in this project for journals that can be turned at the extreme ends of a shaft, that is, those nearest to the tail stock end on the lathe bed extension. Parallel turning of the full length of the shaft is also a requirement, but a rare need, using an existing power fine feed and a combination of lathe change wheels connecting the leadscrew to the spindle. My existing Drummond M lathe uses a single to three phase inverter drive and is capable of screw-cutting threads using a range of change wheels for imperial and metric threads. I always use the half nut fully closed throughout for the whole of the screw cutting operation as the most accurate method of screw cutting. Reversing the lathe spindle is then needed and in my case using a reverse switch on my inverter drive allows me to return the cutting tool to the start point of the thread. A temporary fixed half nut requires the need to reverse the spindle and, in turn, the leadscrew.