Before I get into the tips and tricks, here is the hydraulic fluid I bought for the job. It was much less expensive (half the cost!) than Shell Tellus 68 and the tech rep assured me it had everything I needed and nothing that I didn't.

Let's start with the headstock. The headstock oil drains out of a horizontal 1/2" pipe in the gear cabinet. A trick to deflect the oil from draining straight down into the cabinet of your lathe is to stick a funnel into the pipe after you remove the cap. Before you start, make sure you have a funnel that fits nicely into a piece of 1/2" pipe.

It's a real good idea to put an oil absorbent pad on the floor. You can put whatever jug or vessel you will drain the oil into (must hold over a gallon) down on that pad and the pad will soak up any little spills. Although I didn't photograph it, it's a good idea to stuff a rag in the lower left corner of the gear cabinet below the drain pipe to catch the inevitable drips as you remove the pipe cap and insert the funnel. The oil will run out the large end of the funnel and straight down into your container. NOTE: since I am not actually changing the oil in the picture, I didn't remove the pipe cap.

The drain plug for the gearbox is on the tailstock end of the headstock. You will see two plugs with female hex, one above the other. The lower one is the drain and the other is the fill. To drain the gearbox oil, I used what I call my "little blue funnel". It's long and skinny and has kind of a hood at the big end. I think I once bought it at an auto parts store. Anyway, you will need something like it.

To catch the oil draining out of the gearbox, I used a 1/6 size 4" deep steam table pan.

I placed the pan in the chip tray all the way towards the gearbox drain. I stuck the hood on the funnel in the little opening below the gearbox drain. Then the funnel carried most of the drained oil into the pan. I admit there was a bit of old oil pooled beneath the drain plug, so I took scissors and cut out a piece of oil absorbent mat and stuck it in where the blue funnel had been after I was done draining the oil from the gearbox. That pad soaked up the oil and I just threw it away after.

After draining the gearbox oil it was time to refill it with new oil. It being nearly impossible to add a significant amount of oil into a hole on a vertical face, I cobbled together a funnel with hose extensions. Note how the funnel is held in the chuck jaws. On all 3 of these drain/fill operations you have to watch the oil sight glass. If you overfill it you'll have to drain some back out. I just added a bit at a time while watching the glass. A picture is worth a thousand words:

The only unusual thing about the oil drain plug on the bottom of the Nardini apron is that the plug uses an SAE 3/8" hex wrench, whereas the whole rest of the lathe is metric. Anyway, I used a big aluminum round cake pan to catch the apron oil.

I saved the old headstock and gearbox oil to use around my shop. It has a slightly brown/gray tinge but will still work great for many purposes. The apron oil I put in a waste oil jug which will go get dumped into the oil recycle bin in the auto parts store.

My lathe seems very happy with its new oil, especially the apron. Now that I know how, I won't put off the next oil change for so long.

Thanks for reading!