Threading in reverse - upside down tool or tool at the rear?

Wheat.Millington

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I've been reading about single point threading with the machine in reverse in order to thread left-to-right. Everything I've read says to run the machine in reverse with the tool upside down. If there's room, why not run the tool at the rear of the machine instead? Seems simpler than having to centre up another tool? Any downside to this?
 
I have a South Bend with a 1.5", 8TPI spindle. Threading in reverse would be bit scary as the chuck could unscrew.
Unless the work was small, like maybe a .25" I don't have the carriage travel to thread from the back.
For my needs I typically have the die for whatever I need threaded.
 
If you have a rear tool post it works just fine. Not many lathes are equipped with a rear tool post. Biggest drawback is if the lathe has a threaded spindle the chuck can unscrew.
 
My lathe does not have a threaded spindle. I dont have a rear tool post, but my cross slide has sufficient travel to get back there on the small part I'm working on.
 
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I've never liked the upside down tool, too hard to see what is going on.

Yep, if you can get to the backside, should work great.
 
Tool at rear should work fine if your cross slide has enough travel
-M
 
Practice the technique on some scrap stock first to see if this is something you want to try. If you do this, you'll have to give your tool a hole to start in.

Threading normally isn't really that difficult and it is a technique you'll want to master. There are times when you WON'T have the room to thread from the rear.
 
I have a Grizzly G0602 which has a threaded spindle but also has two dogs to prevent the chuck from unscrewing so operation in reverse isn't an issue on that account. When I added my DRO, I machined a secondary mounting for the compound five inches to the rear so cross slide travel isn't an issue but to cut from the rear, I would have to move my compound to the rear which is a bit of a pain and I really don't have a problem threading to a shoulder as with my variable speed drive, I can slow the spindle down to around 5 rpm as I get close to the shoulder.
 
And remember, unless it's a special part, righty is tighty and lefty is loosy. All that upside down backside thread toward the tailstock with a 180-degree insert mumbo jumbo is gonna send somebody's part to the scrap bin if you're not watchful.
 
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