Thread: SAG 12 Restoration Progress

Originally Posted by swage2011

The hole on mine Looks to be drilled not punched.

Thanks for the reply - best you remember, does it look about the same size?

I'll assume they used a 1.50 mm bit, as a 1/16 bit will not pass through.

Holes in the oil feed lines to the spindle bearings are also used on the SAG 14. My 14 has nylon tubing with holes punched with a hot needle. I inquired about this in a previous thread and learned that copper tube with drilled holes was also used. In the 14 the holes sorta appear to be directed to nearby gearing, but it is not certain that this is the function of the holes.

Carl

What kind of oil is used in the headstock, and how much; or what dips in the oil bath or not? And, are there any other oil lines in there?

I assume the purpose of the hole is vapour presure relief, so an expanding gas bubble in the line doesn't blow an important seal.

Originally Posted by RevetsP

What kind of oil is used in the headstock, and how much; or what dips in the oil bath or not? And, are there any other oil lines in there?

The hs oil is now DTE-25. originally specified as 9.03 lbs of Teresso 47. The inlet tubing end of the oil pump sticks in the oil bath and there are a total of 5 oil lines, counting the pump inlet:



There is an aluminum plate that mounts in the 4 recesses with holes drilled in it under the angled tube that ends with an angle cut end - this plate has holes drilled in it to drip on on selected points amongst the gears.

Note: Obviosly this pic was taken before the hs cleanout was complete....

Originally Posted by <jbc>

I assume the purpose of the hole is vapour presure relief, so an expanding gas bubble in the line doesn't blow an important seal.

The tube with the hole in it is feeding the Gamet bearing at the chuck side of the spindle (left side of previous pic) - the side of the bearing is open and has hollow rollers. It is not clear to me how this arrangement could develop enough pressure to endanger any seals.... Can you explain further?

Originally Posted by TexasTurnado

The tube with the hole in it is feeding the Gamet bearing at the chuck side of the spindle (left side of previous pic) - the side of the bearing is open and has hollow rollers. It is not clear to me how this arrangement could develop enough pressure to endanger any seals.... Can you explain further?

In my limited experience, these pinholes are used to bleed pressure/gas. Perhaps there was once an inner seal on the nose bearing, or maybe the lubrification plan was copied from a design were overpressure/backpressure was more of a concern???

Originally Posted by <jbc>

In my limited experience, these pinholes are used to bleed pressure/gas. Perhaps there was once an inner seal on the nose bearing, or maybe the lubrification plan was copied from a design were overpressure/backpressure was more of a concern???

Perhaps - I really have no idea....

Cleaning the grease and dirt off the pulley to go on the SAG 12 transmission, I discovered this:



It appears the first guy trying to get it off broke the flange, and brazed it before returning. I didn't see this when I removed it, so it is either adhered well or my puller arms missed this area... One never knows what may be found on these older machines.

The dragging track near the inside step was caused by one of the hex head cap screws holding the shaft cover on, and apparently happened because the whole shaft moved rearward - not obvious how this occured as it is now clear by about .090 and it looks like a gear would hit the clutch stop adjustment screw before it moved that far.....

Here's a shot of the hs with the oil distribution tray in place:



I have also made progress on getting the centralized lube system parts:



I happened across a grab-bag of Bijur parts on ebay for under $25, so now I have almost everything I need.

I also have the transmission almost totally together and today was working on making the 8mm x 20mm rubber bushings for the motor coupling to the trans - if you have never tried to turn rubber, it's an interesting adventure. It seems to work best if you put the parts in the freezer at least overnight.... As soon as that's completed, I can fire it up and check functioning of the oil pump and clutches before shoehorning the assembly back into the lathe:



On the less exciting front, I now have all the remaining individual little pieces cleaned of oil and grease, and wire brushed to look better:



I keep the parts that go together on an assembly together in separate zip lock bags as shown - it helps me remember where the parts go.... it's only been two years since I started this project....

is an interesting adventure - here is an example:



In this pic, the rubber is being sheared at the point of the carbide insert, and then folds over on itself, so a thin layer is taken off over the length.

The rubber inserts for the motor coupling on my SAG 12 were hardened and starting to fall apart, so I made replacements. The rubber came from MSC in the form of a tube with .25 id, 1.00 od, by 36 inches long. I did not find a really good way to cut it, but an old butcher knife well sharpened did as well as anything I tried. I suspect a band saw blade with no teeth and sharpened on one edge would work quite well, but I did not have one.



After I got the blanks cut to slightly oversize, I drilled the id to approximately 8mm, but you have to arrive at the correct drill size to use, as it will not drill to size in rubber - the size was determined by which one gave a nice tight grip on the od of a 8mm stub shaft:



Then I used an 8mm stub shaft to hold the blank while I turned it down in od and squared the ends to the desired length. When I got close to the desired dimensions, I switched to a Dremel tool with .5 x .5 in coarse sanding drum to smooth it and put the chamfer on the ends. Sandpaper can also be used to smooth and chamfer, but it is slower. Here are the finished bushings (with a spare for good measure... :



I wasn't sure how tight the bushings should be in the mating 20mm holes, but the old ones still seemed to be a press fit (but that may be because the oil caused them to swell), so that's what I am starting with.....

Geez, I thought my EE was pretty complicated, but it is nowhere near as involved from a engineering perspective. You're doing a wonderful job, and I wished I had documented my Monarch restoration as thorough and clear as this.

Originally Posted by daryl bane

Geez, I thought my EE was pretty complicated, but it is nowhere near as involved from a engineering perspective. You're doing a wonderful job, and I wished I had documented my Monarch restoration as thorough and clear as this.

Well, thank you Daryl - I am trying to document as much of this stuff as I can as I go. I'm not expecting to go back thru this thing in my lifetime (but you never know... ) I'm hoping it will be useful to many with SAG 12's - if nothing else it let's them see what's inside.... I found the postings by Gizmo Wizard quite useful for digging into the transmission - too bad more people don't do this for other less numerous makes and models.....

to check out this rebuilt transmission:



I'll say one thing - the Italians did not want this motor coupling to come loose or shift position: the key was pinned and opposite the keyway was a cone shaped setscrew that fit into a recess drilled into the motor shaft:



I had to make two new pins that hold the rubber bushings - one on each flange was loose from turning under load - and pressed them in:



I did not have a grooving tool narrow enough for the 8mm snap rings that hold the rubber bushing on, so I ground one from 1/4 sq HSS toolbit and made it long enough to also serve as a mini cutoff tool.

As a precaution, I checked the clearance for the coupling halves before trying to mount the motor - using the incremental mode on this depth gage made it easy to see how far the coupling was above the mounting flange for the motor:



I have a question for other SAG 12 owners: it looks like my transmission casting has been cut away at the top to allow limited access to the motor coupling - is this present on all SAG 12s, or did someone modify mine at some point:



The cutout also allows access to the aluminum plug for the intermediate shaft and a screw can be used to pull it - and it does make it easier to align the coupling when mounting the motor. Once I had the alignment correct, the motor just slide down onto its flange (with a little help from the mounting bolts - perhaps I fit my rubbers too tight.... ):

I got the transmission filled with oil, and the VFD temporally attached - I brought the speed up slowly, and sure enough the rotation was backwards. So I interchanged two wires and loosened one of the oil fittings to check oil pressure - and oil did start leaking out after I brought it up to speed. Here is the makeshift test setup:



The module sitting up high on the crate is a regulated 24V, 10A DC supply and the VFD is a Hitachi L200 5HP 3ph running on single phase. I used short jumpers with alligator clips to cobble the setup together for testing - moving the clips allowed fwd/rev and the four speeds to be tested. I saved the numbered collars from the old wires and reinstalled them on these so I could identify which was which prior to turn-on. Here are the speeds I got with the motor running on 60HZ:

gear 1 - 470 rpm
gear 2 - 756 rpm
gear 3 - 1185 rpm
gear 4 - 1865 rpm

Here's a closeup of the meter in action:



I measured the speed with a Mitutoyo digital tachometer I bought on ebay at least two years ago and had never used until now. Switching between gears was fairly rapid - much less than a second. I was able to load it enough in first gear just holding the output pulley by hand to increase the motor current slightly, so it seems to be holding as expected, but won't know for sure until I get it back in the lathe.

Just looked at my transmission and it has the same cutout as your Texas!

Originally Posted by catch22

Just looked at my transmission and it has the same cutout as your Texas!

Thanks for the data point, catch. I guess the factory realized some metal needed to be removed to allow access to the plug for the intermediate shaft....

Can't imagine there's much point to accessing that area with the motor in situ, maybe sight-lines to the motor/input shaft?? The 210 has both that and the countershaft plug fully hidden and lining up was pretty easy.....although the rubber bungs were barrel shaped to help with alignment.

Nifty little tool, what rpm can it read to John?

Originally Posted by BillE

Can't imagine there's much point to accessing that area with the motor in situ, maybe sight-lines to the motor/input shaft?? The 210 has both that and the countershaft plug fully hidden and lining up was pretty easy.....although the rubber bungs were barrel shaped to help with alignment.

Nifty little tool, what rpm can it read to John?

I tried to look it up on the Mitu site, but it has been replaced with a newer model only about a third the size of this one, so here is a pic of the kit:



According to the data sheet that came with it, it is rated at ±1 count to 5999 rpm, and ±2 counts 6000 to 25,000 rpm! I had no idea it would go that high, but it uses a 32.768 KHz crystal clock (same as watches, I think) to get the high accuracy.... It came with three points that slide on the end for different attachment options - the large disc is sized to give FPM readings for surface speed. The disc is supposed to be 6.0 inches in circumference, so it looks like it should read .5 FPM for each count.

As you can see, the cheap plastic case is starting to crack at the corners, but for less than $75 delivered I'm not complaining.... I just stumbled across it while watching ebay for Digimatic linear scales back then. Here is something similar on now:

http://www.ebay.com/itm/AMETEK-1726-...9a03cd&vxp=mtr