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S&S Swan General - Delrin wheel bearing clearance
01 March 2018 - 19:38
#1
Join Date: 10 April 2010
Posts: 32

Delrin wheel bearing clearance

Dear Fellow Swan Owners,

Is there a specified clearance for the delrin bearings for the helm wheel?  I'll be removing the old, worn bearings in the next few weeks and taking them to a local machinist to be used as a model for fabricating new ones.  My plan was to measure the diameter of the wheel axle, or perhaps to remove it also, to give to the machinist for sizing purposes.  However, if anyone knows what the clearance should be, that would be most helpful.  I've read the relevant posts, including the Professor's detailed guidance about removing the bearings - helpful as always.  I've also contacted Nautor spareparts and confirmed that they no longer have the bearings available.  

Thanks very much.

Mark 

Anthea 41/59, Whangarei, New Zealand

 

02 March 2018 - 21:36
#2
Join Date: 19 July 2007
Posts: 66

Mark.

I have replaced all the delrin bearings in our 411.  I have a workshop so I was able to machine the replacements myself and ensure that the clearance was suitable, as your machinist will do, so its probably best to let him have the shaft.

Although Delrin does not swell with moisture like Nylon, it is a relativly soft plastic, so ensure the outer diameter of the new bush is a close fit without needing to be driven into place. If the fit is too tight the inner hole will close up and may reduce the clearance.

Paul 

Hierro 4110 042

03 March 2018 - 06:40
#3
Join Date: 10 April 2010
Posts: 32

Thanks for your quite helpful reply, Paul.  I appreciate your suggestions and will follow your advice.

Best wishes,

Mark 

Anthea, 41/59

 

03 March 2018 - 12:08
#4
Join Date: 02 January 2008
Posts: 1547

Mark and Paul
Here some general advice, but the machinist is the key person, as he can measure the exact diameters.
A modest press fit for the bushing is suggested, 0.02 mm to keep the force small. This will cause the bore to close 0.025 mm, and this also needs to be considered. The recommended bearing clearance after assembly is 0.3 to 0.4 mm. More may be needed if you have hot weather.
Kind regards
Lars

12 March 2018 - 03:29
#5
Join Date: 10 April 2010
Posts: 32

Dear Lars,

Apologies for the delayed acknowledgement of your post regarding the measurements and clearances for the delrin wheel bushings – that was exactly the information I was hoping for.  Thank you very much.  A local machinist has been contacted and we plan to have the new bushings fabricated early next month. 

I also wanted to thank you for your excellent guidance on other threads regarding the method for re-installing Swan windows.  We followed your advice, used Sika 295UV and primers, and read the Sika manual to successfully reinstall the leaky window over the chart table. 

Best wishes,

Mark

Anthea 41/59

 

 

04 April 2018 - 09:32
#6
Join Date: 10 April 2010
Posts: 32

Need some advice regarding steering shaft removal

I’m having difficulty determining how to remove the steering shaft on our 41, which I need to do in order to have new delrin bushings machined.  Unlike the 38 and 47 Swan models discussed on our forum, our 41 does not have a hole in the top of the brake shoe to give access to a set screw.  I assume we have no set screw – is that possible?  If that’s the case, how do I remove the steering shaft?  Do I lightly tap the front end of the shaft to try and slide it through the sprocket and out the aft end of the pedestal?  Or do I try to tap it on the aft side to slide it out the front end of the pedestal?  This approach requires removing the key that holds the wheel in place on the shaft and this key seems quite difficult to coax out of the slot in which it sits.  It also requires removing the hand hold frame bolted to the pedestal.  Or is there a third option I’m not thinking of?

Thanks in advance…..

Mark

 

Anthea 41/59

04 April 2018 - 17:01
#7
Join Date: 02 January 2008
Posts: 1547

Mark

There is a set screw, and it is suggested you drill the missing hole in the brake shoe to access it.
The shaft comes out only through the front end, the forward bearing has slightly bigger diameter.
Kind regards
Lars

06 April 2018 - 09:26
#8
Join Date: 10 April 2010
Posts: 32

Dear Lars,

Thank you so much for your reply.  Based on your advice, I drilled a hole in the brake shoe and, like magic, the set screw appeared!  After removing it, the shaft slid forward easily, as you said it would.  Without your suggestion to drill the missing hole, I would never have thought to do that. 

I do have another quick question, this time concerning the bearing material.  The recommended machinist here in Whangarei, New Zealand, was not familiar with Delrin.  He uses something called PETPR for bearings and bushings on boats.  It looks similar to Delrin, but I could not find it on the internet.  Have you heard of PETPR and, if so, might it be a fine material for the bushings? 

With all best wishes,

Mark

 

Anthea 41/59

06 April 2018 - 14:18
#9
Join Date: 02 January 2008
Posts: 1547

Mark

I think the suggested material is PETPH, pls check. Has low moisture absorption, which is important here. Maybe there is a data sheet?
Lars

08 April 2018 - 10:32
#10
Join Date: 30 January 2007
Posts: 461

Dear Lars,

I cannot but being always astonished by your wise advices which make this forum indispensable!  Just a thing that puzzles me: if originally there was no hole in the brake shoe, how was the shaft fitted there at the beginning?

Daniel 411/004 Luna Menguante

08 April 2018 - 16:48
#11
Join Date: 02 January 2008
Posts: 1547

Dear Daniele

Without the hole in the shoe the brake handle with attached shaft needs to be taken out, this releases the brake shoe so it can be moved out of the way.
The brake shaft end is secured with a split pin (cotter pin for our US friends) inside the pedestal head, and this pin has to be removed first.
Kind regards
Lars

09 April 2018 - 08:29
#12
Join Date: 30 January 2007
Posts: 461

Dear Lars,

thank you! Now I can clearly see how the simple presence of a hole in the brake shoe avoids the tricky reaching of the recessed lower part of the brake assembly.

Sorry to repeat myself but I am always amazed of all the apparently small technical particulars about our boats you know and you are kindly willing to explain: apparently small but extremely important!

Daniel, 411/004 Luna Menguante

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