Help with Vari-Speed Lathe Drive

[Cinnabar325is]

I've done a bunch of research on Reeve's Drivers/Vari-Speed Drives. I know the Clausings are hydraulically actuated and I believe some others like a Hardinge HLV-H are electrically operated.

The lathe in question here is a pattern maker's lathe of German manufacture. The brand is Zimmerman and it is primarily a wood lathe. I do not own it, but I'm trying to figure out the issue for a friend of mine. He bought it a few years ago after it had been cosmetically restored. It appears to have had VERY little use and supposedly came out of a GM plant somewhere in the midwest.

The issue is that the actuating arm for the upper variable sheave is experiencing severe wear. My initial thought was that the upper sheave was not sliding easily enough on the spindle and thus resisting the actuating arm. However, the upper sheave slides VERY easily. This lead to me think the issue might be that the lower variable sheave is not operating smoothly as it should and thus keeping the belt too tight and not allowing the upper sheave to move as it should and wearing out the arm.

Zimmerman seems to have designed some sort of spring loaded mechanism to allow the lower sheave to move in and out axially on the motor spindle. However, the spring mechanism is VERY strong and I can hardly compress it using all my strength. I have no point of reference to know if that is correct.

I would like to take apart the lower sheave and spring mechanism, but I have been totally unable to find any manuals or diagrams for these lathes and I do not want to damage anything in the process. Or kill myself when the spring lets loose.

There seems to be a socket head cap screw threaded into the end of the motor shaft that may be holding the sheave/spring assembly to the motor shaft?

Does anybody have any thoughts or experience with this?

On a side note, my friend is worried about the type of grease used in the spindle bearings (you can see it in the pics). He thinks it is a white lithium grease and wants to know if that's okay for this application. And he's worried the old grease wasn't cleaned out and that it was a different type...

Here are some pics:





Here you can see the actuating arm and the wear in the tip of it:









[URL=http://s50.photobucket.com/user/Euro16v/media/10_zpsxftcs8h8.jpg.html]



Here is looking down into the headstock towards the motor and lower sheave:



Here is the lower sheave along with the possibly spring loaded assembly that allows the lower sheave to move:









Spindle with chuck off:



RPM control:

[URL=http://s50.photobucket.com/user/Euro16v/media/DSC_0645_zps8e6p9gsw.jpg.html]

 

[Cinnabar325is]

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[Cinnabar325is]

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[larry_g]

The fingers that are wearing contact a thrust bearing. When running there sould be no motion between the fingers and the thrust bearing. My first check would be the make sure the thrust bearing is free and turning freely. I also see a oilier on the bearing, has it been oiled regularly? That thrust bearing should act just like the throwout bearing and clutch fork on an automobile if your familiar with auto clutches.

Do you have any manuals or descriptions of that specific part?

On the grease, I would suspect that oil is the preferred lube for the spindle bearings. Oil is standard on all spindles I have worked with.

On edit; I found this http://www.tvtamerica.com/Berges/KRM.htm It shows the bearing I'm talking about on the KR pulley. That site also has genuine Berges belts, though the site also says the pulleys are made for standard belts. Good Luck.

lg
no neat sig line

 

[Cinnabar325is]

Great info, Larry, thanks.

So if I understand what you're saying correctly, the thrust bearing is what the finger contacts and the thrust bearing should not be spinning when the finger is contacting it.

Currently, however, the bearing is spinning and that is why the finger is wearing so badly.

I wonder if I can find a good way to check the ease with which the bearing does or does not rotate around the spindle. So somehow, the pulley is keyed to the spindle, but the pulley slides atop the thrust bearing which is not keyed?

We have no manuals or diagrams of anything to do with the lathe.

 

[larry_g]

Great info, Larry, thanks.

So if I understand what you're saying correctly, the thrust bearing is what the finger contacts and the thrust bearing should not be spinning when the finger is contacting it.

Currently, however, the bearing is spinning and that is why the finger is wearing so badly.

I wonder if I can find a good way to check the ease with which the bearing does or does not rotate around the spindle. So somehow, the pulley is keyed to the spindle, but the pulley slides atop the thrust bearing which is not keyed?

We have no manuals or diagrams of anything to do with the lathe.

In the one picture you posted where the fingers are retracted from the bearing surface, Can you reach in there by hand and turn the outer housing? Will it wiggle at all? Does the picture I linked to help? If not try contacting the company that has the picture and talk with them and ask if the bearing is replaceable, it probably is.

lg
no neat sig line