When to run lathe in reverse.

[Jimsehr]

I know lots of the old machinists do this but some of the new guys should learn this trick for threading from the spindle out to the tailstock. It lets you start a thread cut from a thread
groove near the spindle and cut toward the tailstock. This way you don't have to worry about crashing into a shoulder at end of thread. You run the spindle in reverse and you have to put the thread tool upside down. Today I had to cut a thread up to a shoulder and only had about .02 past thread to the shoulder.
jimsehr

PS can anyone think of another reason to run machine in reverse?

 

[JimDawson]

PS can anyone think of another reason to run machine in reverse?

Power tapping

 

[Marco Bernardini]

PS can anyone think of another reason to run machine in reverse?

When you are using your lathe as a winch to lift your mill, perhaps? :biggrin:

 

[hvontres]

I had some issues with chatter during cutoff, so I mounted the blade upside down and ran in reverse. That way, the tool acts like it's on a spring holder and rather than getting sucked into the work by the cutting forces, it actually gets pushed out, reducing the load. The funny thing was that when I tried out my inserted cutoff tool, it actually works better right side up. Maybe the tip geometry on the inserts helps clear out the chips better.

 

[Tony Wells]

Using a boring bar to cut external edge breaks (or chamfers/bevels) on the "far side" of the part.

 

[sinebar]

...You run the spindle in reverse and you have to put the thread tool upside down...

Please explain why you need to turn the tool upside down in reverse. To me, it only makes sense to turn the tool upside down if the spindle is in foward when you are cutting back side of the work.
Help me understand.


edit : Second cup of coffee cleared my head.
It makes sense when in reverse with the tool on the front side of the work and cutting a right hand thread. Doh!!

 

[Payson Greene]

Holding a file underneath the work, in reverse, lets me see the work, as I'm filing.

Payson

 

[epanzella]

What about threading the back side of the hole with the tool right side up and the spindle reversed? Does that work OK? Never done it but it seems you could see the cut better.

 

[george wilson]

When threading inside shallow lids for pill boxes and the like,I have run the tool upside down and backwards on ordinary lathes. I also made an upside down cut off tool for my 16" lathe. It mounts on the T slots of the cross slide. However,it is so easy to back up the regular cutter,and accidentally run the cut off tool into the work,I seldom use it.

These days,I use the automatic carriage stop on my Hardinge to stop the threading tool within .001" when threading shallow lids. I run the lathe in forward. That stop is extremely handy. I never crash into the work once it is pre set.

 

[cazclocker]

Holding a file underneath the work, in reverse, lets me see the work, as I'm filing.

Payson

Payson, you stole my thunder!! )
I do exactly that too. Holding a file underneath the work lets me see the work's finish as I go - but I have to run the lathe in reverse so the file's teeth will engage the work. Of course, that assumes I'm holding the file by the handle...you can also hold it by the other end but that's what the reverse switch is for!
...Doug