[Peter Gibbs]

Geof I found it Derrrr. Gentlemen, I want to know how to screw cut a left hand internal thread ...I want to make a closed nut in place of a "knock-on" (winged wheel nut)

so it is a cap, with a hex on the end..... 2"ID whithworth 55 degrees and needs an internal thread 1. 1/4 " deep.... I guess I have to grind a threading tool with a lead / clearance on the other end... But I cant figure if I start on the outside or the inside with the tool upside down....spindle in reverse? thanks in advance Regards Peter

[M-man]

You can use your standard tool without modifying it if there arent to many parts to be made. start the threading at the bottom of the cap and thread to Z+ direction. Rotation should be normal...

[Geof]

If you are putting an undercut at the bottom end starting inside and moving outwards, Z+, works okay because you have acceleration space. Otherwise it might make a better thread to run the spindle in reverse and thread inwards, Z-. Your tool then has to be the "wrong way" up.

Does this nut hold the wheel on or is it decorative? If it does not have a function other than looking good save some grinding effort and use a 60 degree tool; it works.

[M-man]

Can he get a rightthreaded tool the "wrong way up" ? If he turns hes tool 180 degrees he must cut the x dimensions on the X- side of chuck center... ROtation for the tool is still the same..

[Geof]

Can he get a rightthreaded tool the "wrong way up" ? If he turns hes tool 180 degrees he must cut the x dimensions on the X- side of chuck center... ROtation for the tool is still the same..

My phrasing was not good. I find I nearly always have to stand in front of the machine and wave my hands around to get things rotating the correct way with the tool in the correct orientation . The toolroom lathes have a 'manual' machine tool placement which doesn't help because most times I am working on a conventional CNC; tool upside down and at the back which is the "right way" up.

For doing a lefthand thread he needs a lefthanded tool upside down at the front. I think??? Peter go stand in front of the d****d machine and wave your hands around!

It is morning and my wakeup coffee hasn't kicked in yet.

[Peter Gibbs]

Gentlemen thanks for you input ...I tried to stand infront of the machine and wave my hands around and it works well done....Geof yes it is a wheel nut but only a temporary one till I get it passed the inspectors Regards Peter