Welcome aboard David. Feel free to ask questions when you get going and please post if you know any answers! More the merrier.

Cheers,

Dave

For thread cutting you need to start by knowing the pitch of the Leadscrew.

Once known you will be able to calculate the ration between that and the mandrel to produce a thread of the pitch that you require. You then need to find the changewheels set up which will provide that ratio.

You mention Norton, so I guess that most will be Imperial sizes, but not sure whether Whit form or Imperial.

Up to 1/2", I would feel inclined to use Taps and Dies. If the thread is large, and likely to be deep, you can set the Die to take a cut less than full depth, and then tighten to finish to the correct depth. Suitable lubricant, often used are Trefolex or Rocol RTD.. You can use either a commercial nut or a newly tapped home made nut as a gauge, to asses thenb thread being cut by a Die. With nuts, you have to accept what the tap produces.

Another item to make or buy could well be a Tap or Die Holder that can "float" to ensure that the thread is concentyric on the raw material. (An off-centre Tailstock or poor drill chuck could pull the Tap or Die off centre resulting in a "drunken" thread which is not be recommended either for strength, effectiveness or looks.

My choice would be High Spped Steel taps and dies. They arer more expensive, but they break less easily in my hands! Needless to say, the cut should be reversed every half turn, to break off the swarf, before taking the next half turn. Taps do not bend easily and break.

To ensure that the tapping is "square" to the work, you can use (make ) bushes to hold the tap square to the work surface, or even go to the trouble of making, or expense of buying, a tapping aid. I made mine from a redundant pistol drill stand and a drill chuck. It has the advantage that if things get tight, the chuck slips before I break the Tap, and there is the chance to back out, clean and relubricate, the Tap, before trying again..

You may find it useful, as an early project to make a Mandrel Handle. Especially if you are cutting up to a shoulder or into a blind hole. This will allow you cut slowly, and stop as soon as you feel that the Tap or Die has reached the end of the hole or is against the shoulder.

If there is enough metal around a hole with a stripped thread, you can either use a helicoil (With its oversize drill and tap) or drill / tap out oversize to insert a threaded bush to revert to the original size thread.

These ramblings will be of some help, I hope.

Howard

Hi David, there is a manual, accessories and lathe work, for the 4" roundbed lathe Machine Tool Manual -A Library which you may find of help.

Regards Nick.