torlon or delrin or what ?

[Birdseye]

found some halves of white balls for bearings on my deck and it looks as if they have come out of the mainsheet block. Look like 1/4 in. Which should I use for replacement - torlon or delrin.

The block on my Sadler 290 is not marked with a manufacturer but it is half way down the boom and subject to shock loads gybing in races.

 

[goeasy123]

I think you would use Torlon because it has a lower coefficient of linear thermal expansion and better flex modulus. You want bearings to be dimensionally stable.

The ultimate might be tungsten carbide made with nickel binder.

 

[Daydream believer]

The ultimate might be tungsten carbide made with nickel binder.

But what would that do to the material it bears on? Should not the balls be matched to the rest of the race?

 

[goeasy123]

But what would that do to the material it bears on? Should not the balls be matched to the rest of the race?

Not that critical in this application. I'm guessing the use of Torlon in marine applications is economic.... somthing stable enough and corrosion resistance.

If you were considering a more critical application you'd want to match the thermal expansion characterists for the components of the bearing.

 

[Roberto]

found some halves of white balls for bearings on my deck and it looks as if they have come out of the mainsheet block. Look like 1/4 in. Which should I use for replacement - torlon or delrin.

The block on my Sadler 290 is not marked with a manufacturer but it is half way down the boom and subject to shock loads gybing in races.

If it's anything significant, to me it's torlon everyday (so perhaps not the dinghy hoisting tackle). I had delrin balls in my mainsail luff cars, after many miles sailing with reefs the first few top cars balls were deformed and almost kept the sail locked up. When I took the old delrin balls off, some were missing, some were oblong, some had become very tiny, I would not want them in anything that is bearing an important load. I changed all balls to torlon and never had a problem since.

 

[B27]

I'm tempted to suggest gybing more carefully.
And upgrade the block to something with 'Harken' written on it.

If the races are plastic, then stainless balls should work well and probably a lot cheaper than Torlon.
If the races are anodized, I'd stick to plastic balls.

Seriously, if you are damaging blocks like this, then maybe a bit of 'give' in the system might be needed?

 

[vyv_cox]

Delrin (acetal) is a thermoplastic that will creep under load. Far from ideal as a highly loaded ball bearing.

Torlon is a polyamide-imide, partly thermoplastic, partly thermsetting. It has very good creep resistance and is widely used in highly loaded ball bearings and similar applications.

 

[Birdseye]

I'm tempted to suggest gybing more carefully.
And upgrade the block to something with 'Harken' written on it.

If the races are plastic, then stainless balls should work well and probably a lot cheaper than Torlon.
If the races are anodized, I'd stick to plastic balls.

Seriously, if you are damaging blocks like this, then maybe a bit of 'give' in the system might be needed?

They arent a lot cheaper - similar price to the delrin but maybe a better idea.

The boat isnt designed for the racing that I do and will only take 3 crew inc me. So its not always possible to get the boom completely in before gybing. Made worse by the "track" being in front of the spray hood. That said, it really sails well

 

[Roberto]

Torlon is a polyamide-imide, partly thermoplastic, partly thermsetting. It has very good creep resistance and is widely used in highly loaded ball bearings and similar applications.

When I bought mine, the manufacturer provided a certificate stating the balls had been "cooked" with a sort of special thermal treatment.