demonboy
Well-Known Member
Here at PSS in Thailand they make cutlass bearings from Torlon, not Tufnol. Any views on this? Are we just talking trade names here? As I understand it Tufnol is just Bakelite.
Torlon cutlass bearing?
- Thread starter demonboy
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reeac
Well-Known Member
No, not the same. Torlon is a polyamide-imide resin whereas tufnol is a phenolic resin-cotton/linen/paper composite. All a bit beyond my A level Chemistry of 1951-3. Cutless bearings normally consist of an outer tube with a fluted lining of either rubber or polyurethane with the latter being longer lasting, I believe. Now it might just be that the Torlon bearing is Torlon all the way through i.e. including the inner bearing surface. That could be a significant difference.
demonboy
Well-Known Member
Indeed. So I'm interested to know the difference between tufnol and torlon in terms of their durability. Since torlon is used in my furling bearings I'd assume that it's a suitable material, but will it wear out quicker? My last cutlass bearing, removed this morning, was ten years old (and a lot of engine hours) and still had a little life left in it, though I don't know what it was fabricated from. The yard here reckons five years for torlon, but that's probably based on fitting them to fishing boats.
Norman_E
Well-Known Member
Torlon in the furling gear bearings is in the form of Torlon balls. Torlon is hard enough to give good wear characteristics when in rolling contact with polished inner and outer races. How well it would wear in a plain bearing situation, sliding rather than rolling, I don't know. Of course there is some sliding contact in a ball race because of the difference in circumference between inner and outer races, so Torlon must have some sliding wear resistance. I suspect however that unless the shaft is highly polished Torlon might suffer as a cutlass bearing.
cliff
Well-Known Member
For your edification http://www.tufnol.com/downloads/data-sheets.aspx - definitely not "just Bakelite"
vyv_cox
Well-Known Member
Torlon is one of the 'engineering plastics', which are polymers based on aromatic chains instead of aliphatic ones like polyethylene, polypropylene etc. Their properties are remarkable, good strength, temperature resistance and fantastic wear properties. Best of the lot is DuPont's Vespel but incredibly expensive, literally made drop by drop. Amoco came up with Torlon as a cheaper alternative some years ago, very successfully. For a while they sponsored a CanAm race car in which the whole engine except shafts was made of plastic, mostly Torlon.
The great thing about these plastics is that they are self lubricating and mouldable, so small parts like gears in electric drills and suchlike are usefully made from them.
Years ago I sponsored research into use of them as face seals in big gas compressors. Everything was looking great until thermal conductivity was modelled, where they failed miserably. Not a problem for a cutless bearing though.
The great thing about these plastics is that they are self lubricating and mouldable, so small parts like gears in electric drills and suchlike are usefully made from them.
Years ago I sponsored research into use of them as face seals in big gas compressors. Everything was looking great until thermal conductivity was modelled, where they failed miserably. Not a problem for a cutless bearing though.
demonboy
Well-Known Member
Nice bit of background info, Vyv, thank you. If it fails, I could always boil down some old saucepan handles and radio sets to make one of Tufnol
