Nylon as a shaft bearing

[charliehows]

am I showing my age by suggesting you investigate lignum vitae?


(oops - post #22 already mentioned it - not quite "special" wood, more 'petrified')

[Nicholson58]

A proper Cutlass bearing is designed to flow water for cooling and flushing. The flat sides or spiral grooves channel water in and float the shaft hydrodynamicly. I think a Cutlass is better than a solid plastic bushing.

[Compass790]

See if you can get acetal then.It must be available in Thailand.
You just need to let water get throught to your stern gland for cooling. I'd guess a couple of longitudinal cuts down the length would be ok.

[njoynthewater]

Back in the day the first plastic water lubricated bushing material that I dealt with was called Thordon(sp). It was a trade name and was recommended for pretty much everything in water bearings. It disappeared and was replaced by 75 durometer urethane. Black was moly filled for lubrication and red was not self lubricated. The manufacturer of the material provided what clearance was to be machined into the bore to allow for expansion in water. It was based on wall thickness so if it was to have .020" clearance with a .010" press fit the bushing would be bored .030" over the shaft size. If you want to see what the latest recommended material for water lubricated bushings contact a water pump repair shop. They may even be able to supply you with bushings from stock. If you need the grooves in the bore they can be cut into the bore by anyone with a lathe and boring bar.

[Cadence]

it is amazing that cutless bearings haven't seemed to have changed in many decades. Maybe the "rubber" has? Is it economics and the old ones still sell and last?

[notiesbob]

https://thordonbearings.com/marine/yacht
https://thordonbearings.com/distributors?c=Thailand

[RaymondR]

It's a longish story as to why I came to use it but I used a piece of wash down hose with a nitrile liner once and since it worked so well continued to use it for about six or so years. The glue I used finally gave up and it fell out but at the time had hardly any wear.

[Epicurean]

One more question: What is a good bedding compound? I.e., one that will hold but I can get the bearing out with reasonable force. It was in with Sika-flex which necessitated a bearing puller. I'd like something a little less permanent so it's easier to change in the future. It came with two screws but I have doubts about their ability to hold it.

[qwert]

I was contemplating an underwater stainless shaft in a delrin bearing a few years back and was advised against it by a plastics engineer as it would cause too much wear on the stainless shaft (!).


I think the reason was that small sand particles getting between the delrin and the steel would embed themselves in the relatively soft delrin and abrade the steel rather like a grinding disc.........