Z axis problem

I

ITteachRET

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Just acquired an old Light Machines mill. Can't get the z axis (vertical) to operate smoothly and consistently. Have cleaned and lubed the ways, adjusted the so-called "gib key" and carrier nut. But it still stops intermittently and groans. Can't trust it to run a program. Anyone have advice on this dinosaur? Is it a motor problem or the shaft connections? Expensive boat anchor if I can't get something figured out.
Thanks!
 
ITteachRET said:
Just acquired an old Light Machines mill. Can't get the z axis (vertical) to operate smoothly and consistently. Have cleaned and lubed the ways, adjusted the so-called "gib key" and carrier nut. But it still stops intermittently and groans. Can't trust it to run a program. Anyone have advice on this dinosaur? Is it a motor problem or the shaft connections? Expensive boat anchor if I can't get something figured out.
Thanks!
Click to expand...
If I'm not being to personal, may I ask what you payed for it ?.
 
Can you get to the ball screw? It could be full of dried grease or gunk
 
ITteachRET said:
$750 with controller box, PCI interface card, all cables.
Click to expand...
Hi, Is it binding on either end of the screw travel?. If you made an adjustment to the table gib to the table feed screw with a worn center area ( from work continually being done at that position ) and with excessive backlash at that area the gib may be too tight. Or possibly a bowed feed screw.
 
It happens at various locations on the vertical table. I've watched the feed screw and it looks good. Sometimes z works fine, sometimes it acts bound up or shaft slipping. Wondering if the "encoder" on the motor end is worn out or gunked up, but haven't torn it apart yet.
 
No ball screw. Years ago I worked on these at the school where I was teaching. There's a funky "soft" kind of shock absorber (buried, of course) where the motor shaft connects to the feed screw. I suppose to prevent strippage or breakage.
 
Hi, forgive me fort thinking it was the x travel. Have to agree with derf that it may be caked grease or a bearing or bushing at the handle.
 
I'm afraid you'll probably have to do some disassembly to see what's going on. Is this a Benchman model?
I saw one for sale at UC Berkeley a few years back and wanted it badly, ran on Windows 98 tho
It was big, about 600 pounds
-M
 
Last edited:
Agreed, complete disassembly, through cleaning, and fresh lubricants --
before you start into the electronics.
 
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