What's new
What's new

Feed Lead Screw Changing Direction on 12CK?

Torquin

Aluminum
Joined
Nov 17, 2014
Location
Powhatan, Va.
A search yielded no relevant results, and the manual I have does not address this, so I need to ask. Can the lead/feed screw direction lever be changed/engaged while the spindle is running, or do I need to stop it every time when I engage in either direction?
Since it has provisions to kick it out at the end of a cut I am thinking it can be engaged while running since it would slow things down considerably to stop the spindle to re-engage the feed screw after every cut (if I'm using the automatic disengage feature).
I have tried engaging while the spindle is running and hear a big clunk, which worries me.

Thanks,
Chris
 
At reduced speeds on other makes with lead screw reverse. My general approach is that if the act of reversing the lead screw makes more than a soft clunk, the spindle is going too fast.
 
At reduced speeds on other makes with lead screw reverse. My general approach is that if the act of reversing the lead screw makes more than a soft clunk, the spindle is going too fast.

Yes..... I have a 14C and now a new(to Me) 12 CK. I feel comfortable with shifting when in the lower third of spindle speeds.

 
Would this also apply to a CW16 that has the lead screw reverse on the headstock between the shift levers? The knob actually screws into the hole for normal OR reverse to lock the direction in place.
My CW does not have the auto stop feature.

Thanks,

Mike
 
Absolutely not (a CW16 owner:))

To elaborate on EDIT

The CK and any real lead screw reverse system both allows that at least at some spindle speed, but far more importantly DOES NOT GET OUT OF TIME WITH SPINDLE.

Switching the reversing lever on the CW or any non lead screw reverse equipped lathe does neither - not allowed with spindle turning and never stays in time with spindle.

Would this also apply to a CW16 that has the lead screw reverse on the headstock between the shift levers? The knob actually screws into the hole for normal OR reverse to lock the direction in place.
My CW does not have the auto stop feature.

Thanks,

Mike
 
Last edited:
I suggest that you limit the top speed when shifting direction of spindle to around 400 RPM.
IMO, I would only do the shifting for a threading operation.
Harry
 
I did a little research (pulled the cover off to install top gasket) and saw where the big clunk comes from. The "gears" that mesh in there have only one tooth each. One big tooth. Perhaps they would be better called "dogs". This would certainly keep things from getting out of line. I was thinking this would make it easier to change gears while running, but I have nothing to back that theory up. It does seem that those huge dogs would take a lot of abuse, more than gear teeth trying to mesh at high speed, and that being just one, there is much more "gap" between teeth for the dogs to get engaged before they actually touch.
I noticed the other dogs, for the changing of the spindle gears, had about 6 teeth each, rather than just one.

Now, the reason I ask is more for feed than for threading. Lets say I'm using the auto-stop feature of the lathe to stop my cut when I reach a certain point, the shoulder of the bushing I'm making. The feed disengages and I have to move the carriage back for the next cut. At this point I have no feed engaged so I need to engage it in order to start the cut. It just seems like it would be a big waste of time to have to stop the spindle, engage the feed mechanism, in whichever direction, then restart the spindle, especially when I'm taking a lot of cuts. Kind of makes the auto-stop feature more trouble than it's worth.

The dogs.
2015-09-01 18.06.27.jpg

Chris
 
You're going to have play with the machine to get a feel for the machine, talking about it is nothing but talk.
IMO, for the application you have described, you'll will find there are quite a few negatives working against you. If you have a nice slow cut, you should be OK, but if you're like me, you'll run the machine at much faster speeds, and you're plan will probably change.
Harry
 








 
Back
Top