Cutting fluid? It should be called 'rusting fluid.'

A whole day wasted today, repairing a piece of equipment that should never have needed it.
You'd think a machinist's rotary table, which is supposed to be used with cutting fluid, wouldn't be harmed by the fluid. But that's apparently not the case with my clunky 'made in USSR' rotary table.

This is the rotary table - the light green thing. It barely fits on the bed of my toy milling machine, but it does and that's all that matters. This photo was taken some days ago. You can see the oil in the sight glass - how it's supposed to look. The pale green liquid is cutting fluid; it is used to keep the cutting tool cool, and lubricate the cut. It's normal for it to be all over the top of the machinery. It flows down to a pump and is recirculated. It supposedly contains corrosion inhibiters, but I've noticed that it can still cause some problems if left sitting on metal for a while.

Or rust, if left sitting inside machinery for a while.
Yesterday, while doing some machining using the rotary table, I noticed that the oil sight window on the side was showing something besides oil in there. Obviously the cutting fluid I use, which is mainly water with a lubricant additive. How on earth did that get in there? It's not supposed to be able to...
But it is. Dammit. I know I have to fix this asap, or I'll have a rusty mess instead of a nice shiny rotary table. These things aren't cheap.

So this morning I disassembled it. This is the underside of the rotating platter. Rust, where there should be clean bare steel. Rats.

It looks like the rust around the bolt and the locating pin is where the cutting fluid gets in. But surely, where the spindle is bolted to the platter you'd expect a water and oil-tight seal, right?

The table's body. More rust. Fortunately the worm gear was always oily and so has no rust.
The cutting fluid and the oil in the table's body don't mix, but the solvents in the cutting fluid have turned the oil into something murky and well on the way to acting like toffee.

Main pivot bearing. It's quite a mystery how those bits of swarf got in here. Possibly they got blown in under the rubber seal around the rim when I cleaned swarf off the rotary table top with compressed air. So, no more cleaning it the easy way. In future it will have to be cleaned by hand with a brush and cloth. Or I suppose, a vacuum cleaner, if I had one that wouldn't be ruined by sucking oily, damp metal shavings.

Gluggy oil. It was originally a clear honey colour. The eye bolts are intended for lifting this thing with a crane, since it's very heavy. I can barely lift it when intact, however unfortunately in my small garage machine shop there's no headroom for a crane. Not even anything solid to anchor a lifting rig. I should just take the eyebolts off - at least then it would be slightly lighter.

The platter and spindle, cleaned. Easy to say, but took ages to do.
It turned out the leak was due to the O-ring (seen on the spindle here) which wasn't fat enough to seal well in the cavity formed by the bevel on the central hole seen in the platter here. When reassembling I used silastic sealant on this seam, so I doubt it will leak again.

The main body and worm drive, also cleaned and ready to reassemble.

Ditto. When reassembling I made sure all internal surfaces were well greased this time. So if it gets cutting fluid inside again, at least it won't rust so badly.
Another design flaw with this thing is that the lips along two sides intended to guide the runnoff cutting fluid are not high enough. On a real milling machine this wouldn't matter much since the bed and its skirts would be larger than this table, so the fluid would still be captured. But in my small machine's case, any runnoff on these sides goes onto the workbench.
As a temporary fix I built up the lips with beads of silastic, as you can see here. It works, but it's awkward to lug this thing around without bumping the delicate beads off. Not sure how to fix this permanently. The rotary table body is made of cast iron, so I'd be afraid of cracking it if I tried to weld beads along the lips.

All done!
The object to the left is a dividing head, with chuck removed. It is used to cut gears and other shapes that need precise division of the circle.
I'd bought this and the rotary table new over a decade ago, at an importer's 'distressed sale'. They are both too big for convenient use on my small lathe and mill, but they were cheap compared to normal prices and I couldn't resist the deal. I figured I'd eventually be getting newer and bigger machine tools, and then these would be useful.

Naturally as life tends to go, that hasn't happened and doesn't look like it can happen for years yet, if ever. So these two have sat on a shelf in their original wooden crates all that time. Till very recently I undertook a project that ended up absolutely needing both of them. With that incentive (and a mounting clamps kit that I had recently bought) I found that actually it was possible to mount these on my milling machine, and although it looks stupid, it works.

So far I've only used the dividing head for very simple things. But now I think of it, I have a quite nice chart recorder that doesn't work due to a couple of small nylon gears that are cracked from age. Sounds like a good reason to try gear cutting. That's something I've always wanted to learn to do, and what I had in mind originally when I bought this.

Ironically, the dividing head also had 'oil problems'. It and the rotary table came without internal oil charges, so I'd added the oil per the instruction books when I unpacked them. The dividing head immediately leaked oil badly. Turned out there's an oil gasket, that was cut about 3 mm too short on one edge. The bottom edge naturally, thank you Mr Murphy. So even before using it I'd had to dismantle it and make a new oil gasket.
It's sitting on that milk crate with a pan underneath, since it still drips some oil due to now having too much oil in it, and it overflows via another route that has no oil seal. I'll be draining it later.

I hadn't planned on writing up today's annoyance, so didn't take many pics.