Anchor Roller Refurbishment?

nigelmercier

nigelmercier

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Live in Kent, boat in Canary Islands
www.bavariayacht.info
I think my Anchor Roller needs refurbishment.
Roller-%231.png

Roller-%232.png


Do I send it away, or fix it myself?
 
nigelmercier said:
I think my Anchor Roller needs refurbishment.
Roller-%231.png

Roller-%232.png


Do I send it away, or fix it myself?
Click to expand...

If you have a lathe that can turn that size get some plastic round and turn them yourself. You may also be able to turn them on a wood lathe if you have one. Else get a local engineering shop to turn then for you.

All you need to do is to decide on the profile you wish to have.
 
nigelmercier said:
I have a lathe. Note sure about what material, profile, or how to do the axles.
Click to expand...

My rollers are Vesconite but the same as the pulley in sheaves would be OK.

Axles I would use a tube the length of the inside of the stem head fitting of the tilting nose with a bolt or threaded bar through the tube. The hole in the roller about 1/2 a mm bigger than the tube o/d.

This is a pic of my bow roller design if it's any help

WEB0430_zpsad2d9788.jpg
 
Last edited by a moderator:
nigelmercier said:
It occurred to me that I could just replace the middle of the roller. Good idea?
Click to expand...

Not sure what anchor you use but for plate shanks it is well worth making the central groove a good fit for it, something like Rogershaw's photo (if it was for a CQR, for example). This should be wide enough for the vertical links of the chain to pass through. The side walls need to be fairly steep to ensure that the shank is held firmly, which prevents the anchor from sliding about on the roller. Your shallow-angled roller is about as far from this as it is possible to imagine, offering almost no lateral support.
 
The rollers are typically acetal (Delrin) and an easy job on a lathe. What Vyv says makes a lot of sense (it usually does) - if I were to replace mine, I'd have ones with a groove to center the shank of my Rocna and prevent lateral movement. The excessive wear on yours suggests that the anchor had room to move (lengthwise though) and thus cause wear, plus it looks like the rollers stopped turning some time ago?

The axles are the real problem - I have the same bow assembly. The axles are tubes that are inserted and then expanded at both ends, and since they sit flush inside the fitting on both sides, there's no room to replace them with a bolt. Plus you'll have to drill them out to remove.

There's less than 1mm on either side for the axle ends, so even a flush axle fitting (axle with a countersunk screw and ring at the end) would be a tight fit.
 
Our roller is a steeper 'V' than yours, more like you lower roller, and when it wore after about 10 years I cut the centre out and packed up the outsides (chopping board). Works a treat. But our wear portion was a bit smaller than yours and I simply cut out enough to allow a chopping board section, cut with a hole saw, at each side.

We cannot have a slot for the chain and shank or the chain would be too low and gouge out part of the bow roller assembly.

Jonathan
 
Neeves said:
... I cut the centre out and packed up the outsides ...
Click to expand...
Pretty much what I was thinking, perhaps make a central section that can be replaced easily. Is there any reason they are in a solid lump?

Any suggestions for suppliers of Delrin (Acetyl), I need 100mm and 70mm diameter?

For the axles I hope to bore and tap the existing rods and use countersunk screws, countersinking the side plates will be a bit of a bugger though.
 
If you develop any side load there is a danger you distort the heads, pull the heads of the thread or pull the heads through the plate. In the absence of looking at the whole set up I'd have gone for M8 but if side loads are not possible M6 would be fine.

You have made a sex nolt or chicago bolt, common on cheap swivels. The sex bolt is a common point of failure, the little locking bolt fails in the manner described.

When you assemble you must ensure the male bolt fill as much of the thread as possible. You have reduced the integrity of the axle as you had a 12mm shaft - its now a 12mm shaft with a hole in the middle, where the male bolt cannot fill the hollow (another point of failure of swivels).

When you retrieve your anchor after a blow and it is well set (and immovable except with time) then there can be massive loads if there is any swell or seas - that snatch load is taken by the bow roller (and that snatch loaD IS enough to bend the shank of an anchor).

Jonathan
 
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