Best way of removing mast corrosion on stainless pin?

Tammany

Tammany

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I want to replace my mast sheaves as they are showing a lot of wear. They are held in by a pin that goes through the mast and then cut flush with 2 small plates to cover up either side. I'm assuming the pin is stainless steel and they are stuck. It looks like hardened compound around the pin which i assume is duralac or similar. I expect they are the original 1970's pins too. The aluminium sheaves have at least 1/2cm freeplay in the bearing.
 
Lots of hot water to start which will help break the corrosion and expand the aluminium. Make sure there is no split pin or that the pin can only come out one way. Penetrating oil may also help as might applying some heat before you try to tap the pin out.

Be prepared for a bit of a battle.
 
Sounds like a Sailspar mast, if so then the pin was only held by the cover plate, we are currently working on a Sailspar mast with the same problem but the sheaves were made of tuffnel, we used the same size pin and the pin knocked out easily, guessing with yours having alloy sheaves corrosion may have set in which may make it more difficult to remove. Good luck!
 
It's a kemp mast but sounds the same construction. The sheaves are in good order except too much play in the middle although I believe they are are designed for wire and I'm going over to 8mm rope. No major corrosion where the pins are from the outside but they are stuck. I haven't tried that much as of yet to remove them though. Will try heat and giving it a good tap when over their next.
 
It's taken me ages to find a pic of the same type but here it is exactly. Mine looks like this but looks a bit gunky where the pin is in the hole.

masthead1-51814.jpg
 
Tammany said:
It's a kemp mast but sounds the same construction. The sheaves are in good order except too much play in the middle although I believe they are are designed for wire and I'm going over to 8mm rope. No major corrosion where the pins are from the outside but they are stuck. I haven't tried that much as of yet to remove them though. Will try heat and giving it a good tap when over their next.
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We are in Brightlingsea, looks like you are in Clacton, if you get stuck happy to pop over, we also stock sheaves (Nylon) that will take rope which if you have not purchased may be what you need. Kemp is now Selden, the boys at Fox's Marina may also be able to help as they are Selden agents.
 
Boats in brightlingsea at underwoods. And yes the sheaves will be needed once I figure out what size they are.
 
Just saved your website, handy that you have swaging facilities for the future. Do you stock a range of sheaves, these ones look quite large at around 10cm but quite narrow. 2 either side and normally halyard goes over one across the mast and then back down but converting over to in mast halyards. I have to say though this design of having the pin flush with the mast exterior doesn't seem to be the best but it's lasted this long so must be OK
 
Just say it's andys boat but she is on the left hand raised bank looking towards the water. Sanded white hull with clear cover with duck tape modifications after the wind during the week lol. Mast is under the boat in it's raw form as it's been stripped. You'll see a broken light hanging off the top. Thanks for that, would be handy if you have the right size parts. Where are you based in brightlingsea? Boat is Tammany but their are no markings.
 
Tammany said:
Just say it's andys boat but she is on the left hand raised bank looking towards the water. Sanded white hull with clear cover with duck tape modifications after the wind during the week lol. Mast is under the boat in it's raw form as it's been stripped. You'll see a broken light hanging off the top. Thanks for that, would be handy if you have the right size parts. Where are you based in brightlingsea? Boat is Tammany but their are no markings.
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We are in the shipyard near Morgans, once I have looked I will send PM.
 
There's a large mast sitting right next to my boat off of a westerly at the moment, perhaps the one you are fitting steps too?
 
I have looked at the masthead and the new sheaves is easy however as you have mentioned the pins are solid in the hole, I tried knocking another pin through however because of the angle the pin has been cut getting a good knock on it is difficult, Maybe someone else on the forum will have another idea! The alloy sheaves would have been bushed and it looks like this is what is making them sloppy. The masthead is welded in so taking the head of is not possible, I do not think the pins have been put in using any compound but just never been out since new. Stainless and alloy just do not go together and this is clearly the problem.
If you do get the sheaves out we have the same size on the shelf.
 
Thanks for taking a look. I'm sure I'll be able to persuade them out somehow even if I have to drill them although I suspect heat will do the trick . How much are they and what size are they? Would the new ones be in plastic?
 
The sheaves are £4.80 each, let me know when old sheaves out and I can pop down (Our garden over looks the yard!) I did not look but would be better with a dividing plate between the sheaves (You may have one) and also check you have enough room between the sheaves if changing to halyards running down the inside of the mast.
 
OK will do, thanks for looking again and will buy them from you when I remove them. I'm off next week so will give it go then.
 
After several doses of penetrating fluid they popped out rather easily using a pin punch and hammer. I think they had a plastic bearing of some sort that has broken apart as they have at least 10mm clearance all round on the pin. The pins are in good condition though.
 
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