Mastodawn

hi internet critters of varying gayness. anyone here who could recommend me grease and oil for a Hobbymat MD65 lathe (=Proxxon SD300)? we have one at my local hacker- and makerspace which has definitively seen better times (see picture) and i want to get it back in working order. however, the manual basically says "use good oil and grease" and i have no clue what the requirements are. looking around on the webs it tells me some complicated stuff and i am confused :(

Laura -> 39c3 DECT: 6011 1d ago

@latuernich For machine ways, the "correct" oil is usually ISO CGLP ("Bettbahnöl"), of "apropriate" viscosity. ISO HLP ("Hydrauliköl") is a good substitute, with better avaliability (HLP 46 can be found in regular home improvement stores).

On such a small machine I'd recommend fairly thin oil. Probably ISO CGLP 32 for the slides. Again, HLP 32 might be easier to get and is perfectly adequete.

For grease, i don't know as much, but I'd probably just take regular bearing grease.

Laura -> 39c3 DECT: 6011 1d ago

@latuernich HLP 46 would probably also me fine, and that's what I know to be availiable at the Bauhaus in Aachen.

For the bearing grease, I'd recommend going to a decent manufacturer, like liquid moly or skf (there are many more, these are just the ones that come to mind for me)

What I've been told to avoid for machine tool oils is automotive oils, since they usually have detergents in them, which aparenty is bad for machine tools.

latuernich 1d ago

@la thank you very much! HLP 46 is available at the local Hornbach (HLP 22 too, although that's probably too thin?). also, i am unsure about the bearing grease: there seem to be many kinds with various parameters (mostly different viscosities and speed ratings) and, according to what i have read online, one should pay attention to these things. either way, Hornbach doesn't seem to sell bearing grease so i will have to resort to online sellers. Unless multi-purpose grease is fine?

Laura -> 39c3 DECT: 6011 1d ago

@latuernich Multi purpose grease will probably be fine. Again, greases aren't really as much my thing, but that should be alright. As long as the nuts aren't completely dry or full of dirty grease you won't do anything wrong on that machine.

The spindle bearings I probably wouldn't touch if possible. I did some reading for one of my machines, and am still quite confused about it.

latuernich 1d ago

@la something that just came to mind: the lathe will probably be used in a rather cold environment because we don't have heating in the metal workshop so maybe the 22 might be the better choice? not sure how exactly it's affected by temperature but if you barely consider 46 under normal conditions...

Laura -> 39c3 DECT: 6011 1d ago

@latuernich 22 will probably be fine.

For reference: The machine I run for work has 68 speced in the manual, and that's what we fill the tank with, and we use 46 for manually oiling things. That's for a "proper industrial machine"

latuernich 1d ago

@la righty-ho, i guess i will buy the oil and spend this weekend messing around with the lathe :3

Laura -> 39c3 DECT: 6011 1d ago

@latuernich Have fun~

Laura -> 39c3 DECT: 6011 1d ago

@latuernich Also: where it's easy to oil, I would use oil, anywhere else, grease.

So, the ways, definetly oil. The Quill, oil. The leadscrews? probably grease, depending on whether you have oil ports or not. The spindle? definetly grease.

latuernich 1d ago

@la according to the manual, everything except the spindle should be oiled so i will probably just do that.

Laura -> 39c3 DECT: 6011 1d ago

@latuernich yea, that seems like a good idea. Tearing apart (or rather properly putting back together) spindles is a difficult topic. I'm probably gonna yolo it on my lathe (It's already apart), but those bearings have 40 years of horrible abuse behind them, and I will put them back in. If I'm ever getting new ones I'll take my time and do my best to do it right.

latuernich 1d ago

@la wait, i think i worded it ambiguously. i definitively plan on also greasing the spindle, i just meant that i will oil everything else. i don't know when it has been greased for the last time but it's not impossible it was more than a decade ago... i doubt it will work properly in the current condition so i would rather put some new grease in it.

Laura -> 39c3 DECT: 6011 1d ago

@latuernich I guess it being specified as yearly means the spindle is decently serviceable... in most machines of that size I know the spindles are designed in a way where lubricating the bearings requires completely tearing the spindle apart (and that usually involves a mallet and some anger to acomplish, which isn't great for the bearings either.)

latuernich 1d ago

@la well, not sure if this is considered decently serviceable... i will see

Laura -> 39c3 DECT: 6011 1d ago

@latuernich Thaaaat is exactly what I didn't meant by decently servicable...

It's doable, but if I were you I'd try figuring out whether you could get replacement bearings beforehand

latuernich 1d ago

@la looking around on the internet the only thing i could find was a video of an italian taking apart the spindle in an effort to restore their hobbymat. they seem to be single row tapered roller bearings, but other than that i was unable to find any information on them. also, buying new bearings for a *precision* lathe spindle sounds like not a fun time for my bank account :/

might just clean the rest and see how it runs tbh

Laura -> 39c3 DECT: 6011 1d ago

@latuernich Those aren't too bad. For "serious" machines it gets pricey, think 200€+ per bearing. On my own small lathe the bearings cost 40€ as a pair (from the same manufacurer as the original ones)

latuernich 1d ago

@la oh, that sounds manageable. i think i will decide whether to touch the spindle after i did the rest.

btw, do you happen to know how important it is for such small lathes to be bolted down to a solid table? afaik we don't have one for it and don't have the space for one either. the manual only tells me *how* to bolt it down, but doesn't tell me if i *have* to.

Laura -> 39c3 DECT: 6011 1d ago

@latuernich Eh. I wouldn't run one for more than a test without it being fixed to something. Maybe try to figure a way to temporarily clamp it to a table?

latuernich 1d ago

@la clamping is a good call, should be possible.

btw once again thank you so much for all your advice.