RE: Cutting threads
First of all if your single pointing the threads using the machine, you must use a thread V Gauge, we old timers call it a Fishtail, to square up your tool bit in relationship with the piece you are threading, this Fishtail also is notched out so you can grind your tool bit to the proper angle for threading. Make sure you have the proper rake and clearance on the tool bit, otherwise you will not get a good finish on the work piece. Also take moderate cuts so the piece doesn't spring or use a center hole on the end of the piece to ensure rigidity. Use either white lead or a good sulfur base oil when cutting the threads. Your finish cut should be light at the end of the thread cutting, and no cut at the end do the finish will be better also. I use a small V shaped file to smooth out the threads, I have had my original Craftsman lathe since 1967, and i still tinker around with it. Good luck on your threading. Jim
--- In email@example.com, <firstname.lastname@example.org> wrote:
When cutting 1/2 - 20 threads on drill rod using may Craftsman 12 inch lathe I'm getting threaqds that fit the nuts, but the threads themselves are rough. Am I cutting too deep on each pass. If not what is the secret to cutting smooth threads. How many thousands should I be cutting on each pass?
- On 02/24/2016 03:59 PM, c.hinton@... [atlas_craftsman] wrote:
Put the compound parallel to the main bed way. Engage the threading gears, and turn the lathe over by hand until the carriage starts to move. Bring the threading tool toward the existing thread using the cross feed until it is close to the major diameter, then adjust the compound until the point is centered in the thread. Advance the cross feed a bit, and adjust until the tool is all the way down into the thread. This will allow you to pick up and continue the thread with minimal error.
I have a 1.0 in. round with 1.0 inch of threads. Is it possible to chuck this round up and extend the threads to 2.0 inches? Can I set up for the 13 threads per inch and engage the carriage feed and slip the round in the chuck so the bit is in the first thread groove? Or is there a better way?