I've just made a Vesconite stern tube (or 'cutless' ) bearing for my boat from Vesconite – I've done several before, along with rudder bushes and even new rollers for my patio doors. As John says, it is a South African product, and you have to order it from there, but they have a bonded warehouse somewhere in the south, Dorset I think. The last piece I ordered arrived in two days. It is expensive – a 1000mm length of cored rod 40 od and 20 id cost me around £90.
It excels at low speed high load situations, especially with water to keep it cool. I wouldn't be happy with it as a headstock bearing as both the speed and the temperature might be too much. Having said that, have a look at the website – they have a calculator to help with machining custom made bushes and I think it includes temperature and speed parameters.
While I agree with John, I'm not sure I'd use the words pliable or squidgy – it is a dense polymer and I think you'd need quite a high point load to see any significant deformation, and that isn't the case with the usual shaft-in-a-bush situation.
Another similar but more easily obtainable material is acetal (trade name Delrin). Again, not my first choice for headstock bearings but useful for lower speed/temperature applications. Try eBay for suppliers.
Finally, don't take my word on this – have a word with someone at Vesconite themselves – they have a very good technical department, an 0800 number for phoning from the UK or, of course, email. **LINK**
Edited By Steve Pavey on 21/04/2016 22:11:38
Edited By Steve Pavey on 21/04/2016 22:13:05