Threading on the Taig lathe! This is a quick and simple demonstration of how the 1152 “Die Holder for Tailstock” is used to hold 1″ button dies on center and enable the Taig lathe to cut standard diameter threads.
The task at hand was to make a small handle out of plastic that could be attached to a little hatch lid for closing the lid from the the inside. I grabbed some scrap 3/4 in Delrin and quickly turned down a length to 1/4 inch diameter. I love machining Delrin as it tends to stay rigid and you can take massive cuts. I was removing 0.100″ diameter per cut!
Next I installed a 1/4-20 button die into the 1152 Die Holder and attached to the tool post (threads over the dead center). The set screws are a bit long but I suspect Taig uses them because they are identical to the ones used in the older style tool posts and they work just fine. The tool holds the die with a snug fit that keeps it on center when installed in the tailstock.
When performing this operation, adjust the tailstock so that the die is within range of the work and the ram is set to allow it to slide by hand. Ensure that enough travel is available in the ram to complete the threading job. Use the ram lever to push the die onto the work and slowly turn the chuck by hand (DO NOT USE POWER). As the die engages the work, the ram will be slowly pulled towards the part. This is one of the advantages of having a ram style tailstock rather than a lead screw. It is important to break the chip every turn or so (depending on the material) and use the appropriate cutting oil. Delrin doesn’t require either of those however.
And that’s about all there is to it. Some notes on threading other materials – as mentioned before, use cutting oil and remember to break the chip when things get tight. Also, steels tend to be quite a bit tougher to thread than aluminum and plastic, and the 3 jaw aluminum soft jaws typically do not have enough grip to hold small round steel parts tightly enough so that they do not slip. Instead, use the 4 jaw with hard steel jaws to get a better grip. Also, hex stock is ideal for threading as it fits squarely in the 3 jaw chuck and will not slip (doesn’t work in the 4 jaw though!). Here are some pictures of the installed hatch handle. Happy machining! -Keith