A picture of that sleeve piece, corrosion eats up some of the material already. The white stuff is just cotton fiber from Q tips.

Are you sure this is Stainless Steel?

Mine were brass FYI but who knows if that was constant. We will not be able to confirm until it is cleaned up

that sleeve is made of brass or bronze. should be quite easy to reproduce it on the lathe.

It has been discolored heavily by all the chemicals I poured over it, the top side(not clearly in the picture, I was trying to display the corrosion near the bottom end) shows some of the original color which to me seems like iron grey. Will tell whether steel or not with my fridge magnets when home today.

Just tested that piece with a magnet, it's either just steel or 301 stainless steel, both react to magnetic field. My original guess is 301 stainless steel as it really needs some corrosion resistance here. Possibly will replace it with a bronze replica, since it's found in other machines(Thanks for sharing that info!)

Some sort of frustration, as the further I go down the restoration the more I feel this machine is a 'lemon' (as Paul Pratt would say about this kind of machines).

During a period, I had to use full strength muriatic acid(31.45%) to get rid of some build up. I will never recommend this method, it's horrible. But that stuff just would not give up any ground to vinegar, citric acid or commercial descaling formula. Five batches of muriatic acid were used for a whole process lasting almost a week.

The previous owner or someone else did restore the machine to some degree, and left headaches for the successor.

To get the nice crusty build up off my pistons I had to use a mix of GUNK engine cleaner, high concentration vinegar, and some brushing with my wire wheel on my grinder specifically for that spring part. I am happy to know my situation in cleaning the groups was not unique and is was not something on the extreme end.

Thanks Ryan, I got some comfort

At the same time, I'm restoring an abused by owner but maintained by professional old Cimbali HX machine(as reference and positive distraction), what a difference and what a fun!