Any safe way to thread away from my chuck on a South Bend 10K?

I must have my drive belts too loose. It doesn't take much to stop the spindle from turning on my lathe at 28 rpm that I use for threading.
 
I loosen my drive belt sometimes when I want to control the spindle torque. It comes in handy when winding coils or making springs. Also useful when threading small threads or up to a close shoulder.
 
Dabbler said:
@twooldvolvos @SLK001 the advice that @mickri is giving is golden.

Even Joe Piecyznski will tell you to never thread away from the chuck if you have a screw on chuck. Joe is on the forum here from time to time, and I hope he chimes in on this thread.

I know that some of our best British friends have made innovative ways to 'keep' the chuck on the lathe including that neat drawbar suggested by @mickri but these devices are more in an 'intermediate to advanced' operators. Take their advice and get used to threading the normal way before trying to use the variants on your threaded spindle.

As a matter of safety and protection for your lathe, the cuts you take for threading should be in the order of .004-.005, so you can slack off the drive belt in case the 'bad thing' happens.. I won't prevent all damage, but it will take care of the worst of it, especially at 150 RPM.
Click to expand...
Your comment, "150 RPM" is a good reminder. Using back gears will make cutting threads much more manageable for me as a beginner. Several others have offered the same wisdom.
 
The true machinists amongst us can thread at faster speeds. On the other hand us newbies to machining need to thread at the slowest speed that our lathe will turn. That's 28 rpm in my case. Until recently I have only used 28 rpm for threading and 166 rpm for everything else. Did some reading in the MOLO and found for most of what I do which is turning steel I should be a 266 rpm on my lathe. I occasionally venture up to 418 rpm. Slow is better starting out until you gain more experience operating your lathe. JMHO
 
mickri said:
The true machinists amongst us can thread at faster speeds. On the other hand us newbies to machining need to thread at the slowest speed that our lathe will turn. That's 28 rpm in my case. Until recently I have only used 28 rpm for threading and 166 rpm for everything else. Did some reading in the MOLO and found for most of what I do which is turning steel I should be a 266 rpm on my lathe. I occasionally venture up to 418 rpm. Slow is better starting out until you gain more experience operating your lathe. JMHO
Click to expand...

This is excellent advice. For someone just starting out learning to cut screw threads, its not the time to look for tricks. Practice using the standard old methods, slowly. As you get better at it, you can start going faster. When your really good at it, you can start trying new things.

Like learning to drive a stick-shift first, or learning to use dials before switching on the DRO.

If someone starts out cutting threads backwards and upside down, at what point are they going to learn the normal methods?

My first few attempts at learning to thread weren't even done under power. I turned the chuck by hand, or on coarse, deep threads, i used a crescent wrench on the chuck jaws to rotate the spindle.

My advice to someone just starting out, would be to grind their tools from hss blanks, leave the DRO off and thread toward the headstock.
 
Last edited:
Ken226 said:
This is excellent advice. For someone just starting out learning to cut screw threads, its not the time to look for tricks. Practice using the standard old methods, slowly. As you get better at it, you can start going faster. When your really good at it, you can start trying new things.

Like learning to drive a stick-shift first, or learning to use dials before switching on the DRO.

If someone starts out cutting threads backwards and upside down, at what point are they going to learn the normal methods?

My first few attempts at learning to thread weren't even done under power. I turned the chuck by hand, or on coarse, deep threads, i used a crescent wrench on the chuck jaws to rotate the spindle.

My advice to someone just starting out, would be to grind their tools from hss blanks, leave the DRO off and thread toward the headstock.
Click to expand...
Thanks for your wise advice.
 
When I first got my lathe I was nervous threading towards the chuck so I wanted a slower speed than my minimum 70 rpm. I didn't have the skill to build a speed reducer yet so I just did whatever I could to learn. By the time I had the experience to build a speed reducer I also had the experience to thread towards the chuck so the problem solved itself!
 
Ken226 said:
This is excellent advice. For someone just starting out learning to cut screw threads, its not the time to look for tricks. Practice using the standard old methods, slowly. As you get better at it, you can start going faster. When your really good at it, you can start trying new things.

Like learning to drive a stick-shift first, or learning to use dials before switching on the DRO.

If someone starts out cutting threads backwards and upside down, at what point are they going to learn the normal methods?

My first few attempts at learning to thread weren't even done under power. I turned the chuck by hand, or on coarse, deep threads, i used a crescent wrench on the chuck jaws to rotate the spindle.

My advice to someone just starting out, would be to grind their tools from hss blanks, leave the DRO off and thread toward the headstock.
Click to expand...


I learned to thread towards the chuck way back when. At home, I thread away from the chuck.

What’s the downside to threading away? Only one I can think of is buggering a thread if you don’t hit your mark. You don’t have a chance to to bail out before the tool cuts. Scrap part.

On the flip side, threading towards the chuck can be very expensive if you mess up. Or worse. I’d rather scrap a part than a lathe.

JoePi only threads away and he has made a living at it for 40+ years.


Sent from my iPhone using Tapatalk
 
For external threads, whether threading toward the headstock, let’s say “normal”, or away, “reversed” is not a big deal as some of you say. But where reversing really saves the day is in cutting internal RH threads in a deep blind hole. I had to do that recently, and because the diameter was small, i had to make a smaller holder for a lay down insert. It’s a normal insert you could use for external threading, but the holder is left hand and you turn in reverse, cutting on the far side of the hole. You just run the tool deep into the hole using a dro, a dial indicator or just a carriage stop, take all the time you want, advance the cross slide to the next pass thread cut depth and engage the half nut normally.

Otherwise, timing when to disengage the half nut when cutting toward the bottom of a blind hole kind of turns this hobby into work.
 
Quote from @Watchwatch :
"What’s the downside to threading away? Only one I can think of is buggering a thread if you don’t hit your mark. You don’t have a chance to to bail out before the tool cuts. Scrap part."



I didn't say that there was a downside. I said:

"For someone just starting out learning to cut screw threads, its not the time to look for tricks."

By that, I just meant that "someone just starting out, learning", should learn to thread backwards untill he learns the textbook way. That method shouldn't be learned at the exclusion of learning the textbook method.

Sorry, I should have been more clear.

As to downsides of away, and upside down threading. Of course there are downsides. Minor, but they exist.
 
Last edited:
You must log in or register to reply here.
Back
Top