Possible to turn left-hand thread with a right-hand lathe ?

[compact8]

My Emco Compact 8 lathe can cut threads but right-hand only and I need to make a lead screw nut with left-hand threads for the Z axis of my mill. May I know if it's possible ?

 

[Asm109]

Uh, you start at the chuck end of things and cut to the free end. Normal spindle rotation. That's it.

 

[compact8]

Uh, you start at the chuck end of things and cut to the free end. Normal spindle rotation. That's it.

My understanding is that the lead screw need to turn in the opposite direction to make it happen. Is this correct ?

 

[markba633csi]

Yes, reversing the leadscrew will cut a LH thread; the cut is started at the chuck end and fed outward toward the tailstock
Visuallize a left handed helix and it will become clear
-M

 

[jwmelvin]

You need a way to reverse the lead screw relative to the spindle. Or a LH tap.

 

[compact8]

You need a way to reverse the lead screw relative to the spindle. Or a LH tap.

That's my understanding. My lathe cannot do that. If the spindle rotates counter clockwise ( normal turning direction ), the carriage always moves towards the chuck.

 

[C-Bag]

That's my understanding. My lathe cannot do that. If the spindle rotates counter clockwise ( normal turning direction ), the carriage always moves towards the chuck.

You are correct. My HF 9x20 is a knockoff of the Compact 8. There are many websites dedicated to modding the 9x20 and one of them is modding to reverse(called a tumbler) the lead screw. You must be careful because the chuck can unscrew. Here‘s one of the many sites dedicated to modding/improving the 9x20.

9×20 Class Lathes – Mini-lathe.com

 

[Just for fun]

Sounds like you are going to need a left-hand tap.

 

[Janderso]

Sounds like you are going to need a left-hand tap.

Might be cheaper and much easier in the long run.

 

[compact8]

Sounds like you are going to need a left-hand tap.

I have looked around but unfortunately no such tap can be found ( trapezoidal 15 x 1.5 mm )