Posted by KWIL on 29/06/2011 16:55:51:
IF Pratt Burnerd thought that all these other alternatives were suitable, then surely they would have packaged some of it under their name and sold it to you, but they dont. So I think I will stick with the correct black stuff on my PB chucks.
Whilst your confidence in P-B is very touching, I think that it’s rather more likely that they’d recommend the stuff that they, or one of their subcontractors, were making the biggest markup on. If somebody made stuff with exactly the same content and marketed it at a fraction of the price, do you really think they’d recommend it? Neither do I…
The problem with the solid phase lubricants on their own is actually getting them to stick to the parts you need to lubricate. PTFE (Teflon) has been noted in the past for ‘clumping’, which isn’t particularly helpful – molybdenum disulphide, on the other hand, is very much like graphite and a really thin smear of this, worked in, is almost unbeatable as a dry lubricant – much better than PTFE, anyway. All you have to do is find a way of getting it there.
The thing about brass swarf is a bit moot, I feel. Chances are that if you are producing this inside your chuck, then it will settle on the horizontal edges of the scroll anyway, and regardless of any other considerations, you shouldn’t leave it there. But I’d still rather get it coated with a bit of moly grease than have it in there dry – the grease is just as capable of lubricating the swarf as well, and in that state it will probably cause less wear until cleaned out, I would have thought.
I’m not an expert in tribology, but it does seem that to a degree with chuck lubrication, you’re damned if you do and damned if you don’t. My take on it is that a really thin smear of moly grease on all of the interfacing parts is likely to leave enough solid lubricant on the mating surfaces to do an adequate job of reducing wear, and if you do a lot of brass stuff or anything else that produces dust, then you should be cleaning out your chucks and re-lubricating regularly anyway – that’s just plain common sense (unless you’re very rich). And that’s not cleaning them out by blasting compressed air in either – that can often make things a lot worse.