Automatic Lathe Toolchanger
Selecting different tool positions on command from the host PC. Just need to get the CAM software set up, and I should be able to start cutting.
A while ago I picked up an old Denford Orac CNC lathe. It's a training lathe Denford made in the 80s based on an Emco Compact 8 but with ballscrews and (very inconveniently) a custom spindle nose taper. At the time Denford made an 8-tool automatic toolchanger for it, but mine didn't come with one and they go for silly amounts of money when they pop up on eBay. So, seduced by the idea of someday having my lathe manufacture parts without intervention while I drink tea, I decided to make my own.
The design is based on a ratchet and pawl mechanism like the original, but I've used two pawls in place of the one on the original, and I've substantially redesigned the toolplate with the intention of reducing the risk of boring tool/chuck crashes - a real risk with this design of toolchanger. I also redesigned the clamping mechanism for the tools. The original used two screws to clamp HSS tools in place, but mine uses four wedge-shaped blocks which clamp the tool in place when they're tightened up.
I manually machined the entire toolchanger (mainly due to lack of access to any CNC machining at the time). Electronics and interfacing to the PC are done. I'm slowly getting the toolchain (CAD-CAM-machine control), sorted, and just cut my first part.
I've uploaded the plans here. Please note the caveats (basically, this isn't a fully tested design and there are aspects that could be improved!).