Internal threading away from the chuck

[Armourer]

Well, thought I would post an update, I managed to get it threaded and I appreciate all the help from everyone here. I thought I could look in and watch my threading tool and stop when required but it was a real pain to do that. So instead I could hear the tool cutting and once you couldnt hear it cut I disengaged the half nuts. It worked like a charm this time, but in the future will rig up a dial indicator to do it properly! Also found a piece of HSS that was in my junk drawer that someone had ground already to make the relief cut to finish the threads into.

 

[Bob Korves]

I recently posted this on a different thread. Run your tool into the hole all the way with the spindle stopped until it bottoms out. Sight across the work and mark the depth on the boring bar with some masking or other tape, or with a Sharpie marker. Now you do not need to look inside the bore. Simply stop the tool before the mark enters the hole. My lathe has a foot brake that stops the spindle basically instantly, so it is possible to get very close to the depth of the bore before stopping the spindle or disengaging the half nuts or feed handle. Goodbye alibi. It is also quite possible to cut or thread out from the hole rather than into the hole. Lots less exciting. YMMV.

 

[magicniner]

If your chuck screws on then look at how you tighten it, if you don't have a tool or tool set which you use to tighten it adequately then it's likely to come off.
My chucks screw on, they accommodate holes for a C-Spanner and the spindle lock allows me to tighten them adequately whilst still being able to remove them with ease. If you can't use a C-Spanner you could make something to hold in the chuck which allows suitable torque to be applied.

 

[Wreck™Wreck]

The best way to internal thread from left to right is to start on the left side, this may be self evident but one never knows.