Bill Shields wrote: ↑
Tue Mar 26, 2019 7:28 pm
...so that you don't have to worry about kicking out the 1/2 nut...you just yank the lever and out comes the cross slide..
Unless the half nut is disengaged simultaneously, that often isn't enough to be of much help. If the shoulder is much larger than the thread diameter, you're still going to hit the shoulder. As I've not experienced such a lathe, can you make your comment more clear? Does the half nut get disengaged along with the compound retraction?
One thing should be mentioned. One acquires the skill of threading manually by repetition. If one avoids the activity, when it's mandatory, it most likely won't be successful. Also, while one is free to provide a thread relief at the end of the threaded portion, that may or may not be an option when working to a print. Learning the process and honing the skill of single point threading is very much a part of one learning to machine. I highly recommend it not be circumvented.
The art of tool extraction and half nut disengagement can be practiced safely by simply stopping at the same point time and again on a straight piece, no shoulder. If destrection of the tool is an issue, practice can be achieved by machining some PVC pipe, whish is soft enough to avoid destruction of the threading tool when the disengagement occurs beyond the target position. It's cheap, and machines very nicely. A great choice in material when practicing technique.
Assuming the most common right hand thread, external, orient the cross slide so the handle rests @ 10:00, with the dial set @ 0. That way, you achieve the most travel of the cross slide with the same motion, which, by using this process, is just a down motion. The half nut is disengaged at the same time the handle is pushed downward, all in one, smooth motion. Try it. It works quite nicely.
One thing. If one uses random cross slide locations, such that the handle may require pulling up instead of pushing down, in a panic, the wrong direction may be chosen. Make a habit of using the 10:00 orientation for that reason.
And, checking pitch diameter with wires? Don't make that hard by doing stupid things, like holding the wires with any kind of restraint.
First, clean out your chip pan/tray before using wires. That way if you drop one it is easier to find.
Place the third wire between your lips.
Set the micrometer slightly larger than the expected reading.
Place two of the wires on the top of the part to be measured, centering them on the item so they don't fall, and separated such that the spindle of the micrometer spans the two wires.
Place the micrometer on top of the wires, which will hold them in place.
Grasp the third wire and place it between the top two wires, but at the bottom of the part. The wire should be free to slide in the thread, but not be able to move side to side between threads.
Once in place, the diameter can be read by tightening the micrometer appropriately.
Repeat the process after taking additional cuts, until the target diameter is met.
Don't hold wires by any means that will prevent self orientation. It takes very little misalignment of the wire to yield an erroneous reading. Even a small amount of tape holding the wires is enough. Learn to use the wires individually. It's not hard once mastered.