Thread: Shaggy's Sag 12

Originally Posted by BillE

I'd probably be more concerned with the gearbox rather than up top, the filter in the pump pedestal would be my first port of call, before running for any length. The colour of the oil should tell you if it's been in there too long. External condition indicates not a huge amount of use, if those hollow gearbox shafts plug up with carbon muck though, a world of pain awaits.

Appears there might have been some exploration in the electricals at some stage, not unusual, but the clip cover over the long duct is gone. What was the thing mounted on the belt cover?

Thanks Bill. Funny you mention that (I assume you're talking about the lower spindle gearbox with the EM clutches), as it's the only sight glass where I can't clearly see the line of lubricant, so either it's over-filled, or dirty. I intend draining some to see what it looks like. I've got a gallon each of the spec'd Mobil hydraulic oils. Haven't seen any specs for required volume of each gearbox. Do you know?

I'll look for and check the pump filter. Is there a way to verify oil flow or lack thereof in the spindle (lower) box?

Two holes in the belt cover were for a shop-made collet closer mount which I removed.

(I don't see anything untoward with the original electrics, just an extra black wire put in to tap off ~115V and an accompanying neutral.)

--thanks

Originally Posted by shaggy

Thanks Bill. Funny you mention that (I assume you're talking about the lower spindle gearbox with the EM clutches), as it's the only sight glass where I can't clearly see the line of lubricant, so either it's over-filled, or dirty. I intend draining some to see what it looks like. I've got a gallon each of the spec'd Mobil hydraulic oils. Haven't seen any specs for required volume of each gearbox. Do you know?

I'll look for and check the pump filter. Is there a way to verify oil flow or lack thereof in the spindle (lower) box?

Two holes in the belt cover were for a shop-made collet closer mount which I removed.

(I don't see anything untoward with the original electrics, just an extra black wire put in to tap off ~115V and an accompanying neutral.)

--thanks

Yep, one down in the base. Haven't got a 12 manual conveniently at hand, I'm sure if someone doesn't pipe up, you can download it.

Graziano specs oil by weight for their own peculiar reasons. Specific gravity for Mobil stuff should be somewhere around ~ .7, no doubt listed in a spec sheet though. 1 US gal= 4 litres = 2.8kg = somewhere around 6lb, if I haven't stuffed the conversion!

It's a pity you can clean the sight glass without pulling the box apart, dirt film is even more prevalent in the electromagnetic boxes.

Oil flow can be checked by disconnecting an external copper line momentarily I guess, you'd either have to have broken drive tang, bad vanes or some foreign object that chewed up the inside of the pump body to have oiling issues I'd expect, they seem pretty good.

Edit: Assuming the oil pressure switch isn't bypassed - unfortunately, very common on these - the motor won't stay running without the pressure signal.

Originally Posted by BillE

Yep, one down in the base. Haven't got a 12 manual conveniently at hand, I'm sure if someone doesn't pipe up, you can download it.

Graziano specs oil by weight for their own peculiar reasons. Specific gravity for Mobil stuff should be somewhere around ~ .7, no doubt listed in a spec sheet though. 1 US gal= 4 litres = 2.8kg = somewhere around 6lb, if I haven't stuffed the conversion!

It's a pity you can clean the sight glass without pulling the box apart, dirt film is even more prevalent in the electromagnetic boxes.

Oil flow can be checked by disconnecting an external copper line momentarily I guess, you'd either have to have broken drive tang, bad vanes or some foreign object that chewed up the inside of the pump body to have oiling issues I'd expect, they seem pretty good.

Edit: Assuming the oil pressure switch isn't bypassed - unfortunately, very common on these - the motor won't stay running without the pressure signal.

It's not bypassed, not at the switch anyway. I'll check. If I pull a lead off the switch while it's running, the machine should stop.

I have the manual, actually two different versions now, with both early and later electrical diagrams. Mine's later, Ser. No. 4511, btw. (Maybe 1980?)

Will drain the lower box just to be sure, might see something through the sight glass in the process (hopefully nothing living)

When you pull the lever for running the spindle up it should run correctly for normal turning
Those pressure switches are mostly bad The DC current for the clutches goes over it directly Normaly it does not switch with any current on it but If it switches it puls a hefty arc

Peter

Originally Posted by Peter from Holland

When you pull the lever for running the spindle up it should run correctly for normal turning
Those pressure switches are mostly bad The DC current for the clutches goes over it directly Normaly it does not switch with any current on it but If it switches it puls a hefty arc

Peter

Thanks Peter.

Strange the pressure switch contacts would go bad from arcing. As you say, under normal circumstances the contacts would be closed well before the clutches were actuated and drawing real current.

Do you know is there a replacement pressure switch available, or the threshold psi?
I don't think mine is bad, but I'll check. I'll be keeping an eye on the oil flow, in any case.

shag, your avatar ... sprint roadracer ? hole through the tank for air to the carburetor ? got photo ?

I forgot which pressure
I put a gauge on it to check
A better solution IMHO would be to have a pressure gauge in sight

peter

Originally Posted by EmanuelGoldstein

shag, your avatar ... sprint roadracer ? hole through the tank for air to the carburetor ? got photo ?

That is the Bruno Spaggiari works Ducati 450 desmo single, ca 1969. My personal pin-up machine at the time, and the object of much youthful obsession. Pic is out of my scrapbook of newspaper clippings from British broadsheet newpaper 'Motor Cycle', back when I was an 18-year-old apprentice motorcycle mechanic.

Originally Posted by Peter from Holland

I forgot which pressure
I put a gauge on it to check
A better solution IMHO would be to have a pressure gauge in sight

peter

Thanks Peter. I might try that!

Pressure should be in TT's Sag 12 thread adventure, vaguely remember it was somewhere around 50psi when I put a gauge on it. I think he explained in some detail the logic of the system - or maybe it was my sparky. Take-away, it was a good idea to retain the function as Graz intended.

The sensor is 1/8" bspp, which might present sourcing difficulties over there, Ugo probably sells them if you were really stuck, but this one sounds like it must be ok.

The old desmos must have been murder to live with long term, did have a soft spot for the one with the transparent tank "fuel gauge", back in my younger years. Remember one was displayed at one of the independent dealer/tuner/race shops back in the early 70s just behind a normal window, probably last 5 seconds if you tried that now in that less than salubrious suburb!

Originally Posted by BillE

Pressure should be in TT's Sag 12 thread adventure, vaguely remember it was somewhere around 50psi when I put a gauge on it. I think he explained in some detail the logic of the system - or maybe it was my sparky. Take-away, it was a good idea to retain the function as Graz intended.

The sensor is 1/8" bspp, which might present sourcing difficulties over there, Ugo probably sells them if you were really stuck, but this one sounds like it must be ok.

The old desmos must have been murder to live with long term, did have a soft spot for the one with the transparent tank "fuel gauge", back in my younger years. Remember one was displayed at one of the independent dealer/tuner/race shops back in the early 70s just behind a normal window, probably last 5 seconds if you tried that now in that less than salubrious suburb!

Sounds about right, but for the time being I think I'll 'leave well-enough alone'.

This might be the Ducati you were talking about. My 1975 750 SS was similar, though not quite THE ultimate classic that (this) the 1974 model turned out to be:



..hmm. I think it's starting to dawn on me why I had to have a Graziano

That was the one with the infamous fly molded in the tank transparent stripe.

Originally Posted by shaggy

Sounds about right, but for the time being I think I'll 'leave well-enough alone'.

This might be the Ducati you were talking about. My 1975 750 SS was similar, though not quite THE ultimate classic that (this) the 1974 model turned out to be:



..hmm. I think it's starting to dawn on me why I had to have a Graziano

I don't remember that frame colour, I think it was silver and maybe a little earlier than 74, and the see through was wider and further back, but that's probably dodgy memory, recall the akronts though!

Funny thinking back - into motocross at the time, could barely give away old bikes when upgrading to the new model, because the changes were so profound year to year....now those same comparative heaps of shit command lots of pennies.

Did have an infatuation with Alfas for a while, which might explain me....did see a historic picture of the factory in Milan.....rows of Grazianos.

Reality bites (Shaggy's Sag 12 saga, cont'd)

To be honest, at first sight the condition of my Sag 12 was a disappointment. There were deep scars on the cross slide from crashes, the cross slide screw had a frightening amount of backlash, and the compound was binding mid-way. Three of the original control handles were missing or had poor replacements. I could only hope that was the worst of it.

I had to face the fact that my Sag 12 had endured years of abuse as a dreaded college training lathe. And that I had no choice but to load it up and get it home. It was mine, for better or worse.

I put the disappointment aside. The machine would never be a showpiece, but I could at least make it usable again.

A few days later I finally had time to check out the problem(s).

The amount of cross slide backlash amounted to a half turn of the handwheel. One of the two cap screws securing the leadscrew nut (or pillow block, as it turned out) had stripped out and broken away a piece of the CI casting where the original M8 blind hole had been drilled and tapped, rather too close to the edge. The block was trying to pivot on the remaining bolt.





Fortunately there was enough meat left in the casting to allow drilling the two blind holes right through, and tap them for 1/4"-20 cap screws. I made a pair of 1/4" ID shouldered steel spacers to fit the counterbored holes in the cross slide and center the new screws.





There was now a healthy length of thread (and appropriately coarse, for the material, as sadly doesn't seem to exist among Metric threads) to pull the block up tight, reducing the backlash to a minimum.

And there are more repairs, and some missing parts still to be made.

So there you have it, one of Life's lessons relearned. Sentimentality be damned. Nothing is perfect!
Once over the disappointment, however, the bright side is that everything seems to work, and what's imperfect can and will be improved, over time.

Oh, made a new tapered handle for the leadscrew half-nut actuator:




Next: The mysteries of the Graziano taper attachment, and further repairs...

Also, (hopefully) getting rid of that #$$%! canary yellow paint!

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Originally Posted by 706jim

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Thanks - fixed!

Nice machine! Congrats!

Originally Posted by ACHiPo

Nice machine! Congrats!

Thanks. G/f had to tear the machine out of my cold greasy hands for a few days, due to a Thanksgiving holiday trip, but I will be back soon with more TLC (for the lathe )

Need to complete: Transmission oil change, filter cleaning, oil pressure verification, timer relay circuit testing. Then I want to double check operation of the clutches and associated switchgear, before I start running the machine regularly.

Also, my static phase converter (only used to start the RPC idler motor) decided to blow the stuffing out of it's starter cap. I've got a replacement cap and a complete backup unit waiting, and am looking forward to firing her up again.

Shaggy

Nice looking SGA12.
I bought mine couple years back from a Calif business that was closing.

Yup very heavy moved best on a 5K pallet jack.
I used four SUNNEX 8000 lbs antivibe levelers so I can avoid having to push my cherry picker to put on and off the pallet jack.

Other then old multi-language manuals and not a lot of details they are great machines. I have a spare clutch box that needs a couple of clutches reworked (future project) so my biggest worry is a non-issue.

Look at https://groups.io/g/Graziano-Lathe/files and photos for wiring schematics Two versions of 12 and then the 12S so variations between them to be found.

By the way my lathe has ATF in clutch box. The previous owner has had used it for a very long time in this unit. He started using after having to have two clutches replaced from disc wear. The west coast re builder for SAG advised using the ATF as the clutch units use euro automatic transmission parts. I look for the RED line in the sight window.
I will not question the logic as it is working.