Stopping the carrage on my lathe at a preset spot. Can it be done ?

stern

Active User
Registered
Joined
Apr 2, 2013
Messages
230
Kind of a weird question, but Im looking for a way to "disengage" the carriage from the feed screw on my lathe. Currently I can just use the lever, but want to put an adjustable stop on it, mostly for safety. Sometimes I need to get really close to the chuck and it gets a bit nerve racking watching and playing "beat the buzzer". So far I have had no issues, but find it really draining and would love a way to make it stop feeding at a selected point. The lathe I have is a PM1027 and think it uses a half nut type idea on the feed ON/OFF handle, but not sure. I figured I would check here and see if anyone had ever done something similar. Would be nice to be able to run up to a collar and have the feed stop at the same spot every time.
 
- - - Updated - - -

Kind of a weird question, but Im looking for a way to "disengage" the carriage from the feed screw on my lathe. Currently I can just use the lever, but want to put an adjustable stop on it, mostly for safety. Sometimes I need to get really close to the chuck and it gets a bit nerve racking watching and playing "beat the buzzer". So far I have had no issues, but find it really draining and would love a way to make it stop feeding at a selected point. The lathe I have is a PM1027 and think it uses a half nut type idea on the feed ON/OFF handle, but not sure. I figured I would check here and see if anyone had ever done something similar. Would be nice to be able to run up to a collar and have the feed stop at the same spot every time.
http://www.hobby-machinist.com/showthread.php/14769-Quick-Carriage-stop?p=113593#post113593
 
I've made many such things; all ad-hoc (but reliable). I have never seen a general purpose device sold by a manufacturer -probably because of the varied ways of attachment as well as liability concerns.

I have already designed a mechanism for this for my PM1236 which operates with pneumatic switches and solenoids. -Just haven't gotten around to building it yet. It has a 2lb actuation button and a 4lb solenoid that has adjustable throw.


Ray

EDIT: The 2 and 4 pounds are actuation forces -not the physical weight of the devices... ...



Kind of a weird question, but Im looking for a way to "disengage" the carriage from the feed screw on my lathe. Currently I can just use the lever, but want to put an adjustable stop on it, mostly for safety. Sometimes I need to get really close to the chuck and it gets a bit nerve racking watching and playing "beat the buzzer". So far I have had no issues, but find it really draining and would love a way to make it stop feeding at a selected point. The lathe I have is a PM1027 and think it uses a half nut type idea on the feed ON/OFF handle, but not sure. I figured I would check here and see if anyone had ever done something similar. Would be nice to be able to run up to a collar and have the feed stop at the same spot every time.
 
Last edited:
Hmmmm never actually thought about using a solenoid to release the feed ..... great idea :) guess my mind is stick stuck in "mechanical linkage mode". What ever I end up using it will be home made, just figured I would get some great ideas here, and that was sure a good one :)
 
I have seen a couple of articles that had methods that might be adaptable to many lathes. One was mechanical and basically was a homemade lever adapted to the half-nut with linkage to the left of the carriage that hit an adjustable stop block mounted on the bed. The other was for a lathe equipped with VFD. A VFD can be programed to e-stop quickly and can even apply a variable braking force. The VFD e-stop method might be a problem with screw-on chucks.

I will see if I can locate the source of the two methods and post information on them.

Benny
The Orphanage Never Closes
 
My Hardinge HLVH has a built in carriage stop that will stop to .001". It cannot be adapted to other lathes,though.
 
my brothers Logan would disengage the half nut when it contacts the carriage stop. Isn't that what happens on a Bridgeport quill down feed when it contacts the stop or something like that.
 
That is really nice, going to have to open up my machine and see exactly how the 1/2 nut works :)
 
If you find it difficult to set up an automatic cut-out, consider a carriage stop with both a hard stop and a dial indicator, similar to the one I made for my Hercus (same as SB9A). I have it set so that the needle goes around 4 times and hits zero when the carriage hits the hard stop.

PB130011a.jpg

When I'm running the carriage under power, I can see (peripheral vision) when the dial starts to move and drop out of power (either clutch or half-nuts) with about 0.005" left to go. I finish by turning the carriage wheel by hand to the stop. If I'm a bit late when running under clutch, there is enough slip to prevent the carriage from hitting the chuck. A very rare occurrence.

PB130011a.jpg
 
Back
Top