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Sag 12 Headstock Not Pumping Oil?

catch22

Aluminum
Joined
Sep 23, 2006
Location
CANADA
Hi everyone, I finally got around to cleaning the Graziano Sag 12 transmission and changed the oil in it. I also drained the headstock oil and put fresh oil in it, got it wired up and it started right up, first time I have heard it run in almost 15 years. Now the problem is that the top sight glass there is no oil moving. Is there a way to prime the headstock, I didn't want to run it too long since it's been sitting for so long. Any help would be appreciated.
Thanks Mike
 
Mike,

I can't see oil in my tell-tale window either, but that is because the glass is stained or dirty.

How about first lifting the headstock cover and seeing if oil is flowing onto the aluminium oil distributor plate (photo courtesy the late Texas Turnado).

If the pump isn't working/self-priming, perhaps try fitting some flexible tubing to the pump inlet pipe and feeding it some oil from above the headstock cover level? Sorry about the mist of oil covering you by now :D

I haven't looked on my lathe, but the other photo (spindle removed) shows there is a short copper pipe on the suction/inlet side of the pump.

The photo was taken by a PM member (sorry I can't recall your name) who changed out his bent spindle many years ago. Because the spindle had been removed, the oil pump inlet pipe can be seen.

Or...how about fitting a length of clear tube to the outlet pipe and suck....

An old trick used on tired engines with external oil pumps (e.g. Holden V8's) was to remove the oil pump and coat the pump gears (or vanes) with Vaseline. They would self-prime after doing this, and continued to do so thereafter.


Sag 12 head stock oil distributor plate, Texas Turnado 01.jpg emptycase.jpg
 
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Not working or just the pinwheel not spinning? Have found the fit of the cover can affect the latter....and of course, running the spindle in reverse is the other oil free situation.
 
Not working or just the pinwheel not spinning? Have found the fit of the cover can affect the latter....and of course, running the spindle in reverse is the other oil free situation.

Bill,

I don't think the Sag 12 headstock sight glass has a pin wheel.

I am almost certain the Sag 12 headstock oil pump works equally well when turned in either direction. Texas Turnado explained how it worked in his rebuild thread:

Quote from Texas Turnado: "The eccentric bronze bushing is free to rotate in the housing, but has two stops. The friction from the vanes cause it to rotate against the first stop, which is set to hold the eccentric in the correct position to pump oil out thru the correct port. When the rotation is reversed, the eccentric rotates with the vanes until it hits the other stop, which is positioned to pump oil out thru the same port as before - a rather simple but clever design, me thinks...."


P5270029.jpg P5270027.jpg
 
I had the same problem on my 12S
took out the pump Cleaned it and filled it with oil while I had the tube off
That did not work
Then I realised the vanes had some play
I then put in a somewhat oversized centre tube (see picture in previous post)
After a while it pumped again
I would remove the lid anyhow because it can take a while before you see the oil
 
Bill,

I don't think the Sag 12 headstock sight glass has a pin wheel.

I am almost certain the Sag 12 headstock oil pump works equally well when turned in either direction. Texas Turnado explained how it worked in his rebuild thread:

Quote from Texas Turnado: "The eccentric bronze bushing is free to rotate in the housing, but has two stops. The friction from the vanes cause it to rotate against the first stop, which is set to hold the eccentric in the correct position to pump oil out thru the correct port. When the rotation is reversed, the eccentric rotates with the vanes until it hits the other stop, which is positioned to pump oil out thru the same port as before - a rather simple but clever design, me thinks...."


Interesting. I think I'd have to see in the flesh what John described to get my head around the pump operation he's describing.

Do wonder what happened with his lathe too, got the impression, the stepchildren(?) weren't likely to appreciate his labours.
 
i dont know about this pump, but often the top cover needs to be ground to reduce the clearance.
 
So I took the top cover off and the oil is pumping fine, it was just hard to see it in that sight glass. Thanks for everyone's help.
 








 
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