Rudder bearings for Westerly Griffon

[Trevor Baldock]

I read somewhere that PET bearings are stronger than nylon, what exactly is PET, where can you buy them and how much are they.
Thank you Trevor

 

[UK-WOOZY]

i thought it is Delrin (Polyoxymethylene) that you should be getting

 

[VicS]

I read somewhere that PET bearings are stronger than nylon, what exactly is PET, where can you buy them and how much are they.
Thank you Trevor

Polyethylene terephthalate ......... widely used for packaging esp drinks bottles etc

 

[vyv_cox]

Acetal is the material of choice for rudder bearings. Delrin is a trade name of this material.

 

[Trevor Baldock]

So how long will bearings in Acetal last in my Griffon, how much and where can I get them

 

[vyv_cox]

So how long will bearings in Acetal last in my Griffon, how much and where can I get them

Acetal can be bought in rod or tube form from many suppliers, Google or Ebay a common source. Polypenco is a company I have used in the past, I assume they are still in business.

Or go to a small engineering company if the bearings are more complex. They will usually be able to supply and manufacture, it is a very common material. Example here: Sadler 34 and 32 rudder bearings

 

[vyv_cox]

Or Direct Plastics | Engineering Plastics | Large Stocks In All Sizes

 

[Daydream believer]

If you supplied an acurate drawing & said what material you wanted I could probably turn some bearings for you
Select the plastic from plastic direct online. They describe the performance of each material in a clear & precise manner on their site.
PET has a limit of 60mm diameter

 

[Boater Sam]

Nylon adsorbs water and swells slightly, not the best for rudder bearings.

 

[Daydream believer]

Never use nylon. Swells & jams the shaft.

 

[Boater Sam]

Never use nylon. Swells & jams the shaft.

13 minutes late there Bud.

 

[Daydream believer]

13 minutes late there Bud.

Try & keep up
Read posts #6 & #7
Rules of the forum

 

[Rhylsailer99]

Uhmwpe is a good plastic but can be a nightmare to machine

 

[DinghyMan]

We make Westerly rudder bushes in UHMWPE, Delrin, Acetal, and PET - (Polyethylene Terephthalate)

We sell almost all our Konsort / Merlin / Griffon ones in PET, there is a write up in Septembers PBO showing a customer of ours fitting a set

We use PET because its better - see below for definition of better - than the other similarly priced alternatives

To quote Direct Plastics: PET Rod | Direct Plastics Limited

What are the mechanical properties of PET Rod?
The data sheet tells us its around 30% stronger than acetal, its also around 25% more rigid. It not also has a better working temperature but its expansion rate is much lower. Expansion due to moisture absorption is also incredibly low, some 60% better than even Acetal.

 

[mickywillis]

Drawings for the bushes are on the Westerly Owners Club website, available to download.
I had a set made by a friend in UHMWPE, apparently a bit of a sod to turn, but he made them OK.
Dimensions are in Imperial, so make sure you can read those OK!

 

[mickywillis]

Or here!!

 

[DinghyMan]

There are two sizes of bushes - the WOA drawings are for the Mk 2
Mk 1's have smaller main bushes - the long ones - but Mk 1's may have Mk 2 pintles & the larger bushes or even a mix of the two just to add to the fun

 

[Boater Sam]

Try & keep up
Read posts #6 & #7
Rules of the forum

I'm keeping up quite well thank you. My post #9 preceded yours, with the same info. Please don't be so arrogant.

 

[Daydream believer]

I'm keeping up quite well thank you. My post #9 preceded yours, with the same info. Please don't be so arrogant.

Are you so stuck up that you could not see the joke, or did you not bother to follow the link?

 

[mickywillis]

There are two sizes of bushes - the WOA drawings are for the Mk 2
Mk 1's have smaller main bushes - the long ones - but Mk 1's may have Mk 2 pintles & the larger bushes or even a mix of the two just to add to the fun

I have a Mk1 Griffon (1981) and the dimensions of the bushes in the drawings fitted to my boat without a problem? The main thing to be aware of is the dimension of the rudder shaft I believe is actually 9/16ths?