Sticking Servo Power Feed Clutch?

A friend of mine has a Clausing 8520 mill with a Servo brand power feed on the table (probably a model 140, or similar). He's put it to good use
for many years as a free-lance custom machinist working out of his home. Lately the clutch mechanism that disengages the power feed has been sticking. Ordinarily, when you move the power feed control lever to center, the gears are supposed to disengage so you can use the handwheel. I think there is a spring loaded mechanism that pops the drive pinion down away from the big bevel gear.
Does anyone know if this is easy to fix? It could just be fossilized lube, or it could be that the spring is busted or has taken a set. I'm also not sure what would be involved in getting far enough into the drive to diagnose and fix it. I suspect it may have to be removed from the table, which is not a quick process. Parts shouldn't be a problem if he can get it apart.
Thanks!
Doug White
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snipped-for-privacy@alum.mit.edu (Doug White) wrote:

Doug,
You might want to ask on the clausing_lathe_and_mill group on http://groups.yahoo.com/group/clausing_lathe_and_mill /
I'll take a peek inside, nasty grease, infiltration of coolant, or a broken spring sounds like the problem. If you get too far in disassembly, take digital photo's to mark your way in.
Wes -- "Additionally as a security officer, I carry a gun to protect government officials but my life isn't worth protecting at home in their eyes." Dick Anthony Heller
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snipped-for-privacy@alum.mit.edu (Doug White) wrote:

I've had my Servo clone power feed apart several times while replacing a fried speed control pot. It was not difficult, and the operation of the clutch mechanism is obvious when the cover is removed.
It is worthwhile to remove the unit from the mill and clamp the mounting plate in a vice while one is disassembling the Servo unit.
Joe Gwinn
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says...

The pinion stays engaged all the time, it has a two part shaft with simple coupling halves that mate with each other. The lower shaft/coupling gets cammed up directly by the lever and returned by a hefty spring.
Servo has all the manuals online, so there are good diagrams available. I have had my import version apart, and the illustrations are identical to the Servo so hopefully they come apart the same. Just unscrew the bolts on the bottom and the entire lower mechanism will drop down, the final drive unit and upper housing can stay on the machine.
They are easy to remove from the mill anyway, unscrew the hand crank, slide off the bevel gear and undo two bolts in the drive unit under where the gear was. Take care to keep the various shims in the correct places if any are installed.
--
Dennis


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snipped-for-privacy@wowway.com (DT) wrote:

Thanks! I've passed this along to my friend, and as soon as he gets a lull, he's going to take his apart & see what is going on. I looked at the exploded diagram, and it looks like a very nice design. I figured the pilot light & fast feed switch might be wired up to the upper housing, but they use a light pipe & push rod to work with the wired bits attached to the bottom assembly.
Doug White
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Yeah, I was pleasantly surprised to see this when I took mine apart, they separate completely into two pieces. And the Chinese had the good sense to copy them exactly...
Now taking it any further apart then that, well, let's just say there are a lot of close fitting parts in there.
--
Dennis


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