maintenance on masthead blocks

[allanbranch]

While my mast is off my boat at the yard, any tips on cleaning the aluminum mast head blocks? ..or do they even need any cleaning/maintenance?

[psk125]

They look pretty simple & rugged, without even bushings, and they seem to have held up pretty well. Are they 20 some years old, perhaps? It might be nice to put some grease on the shaft. It might help them last longer and any that spreads around could help slow oxidation that could be going on. Other lubricants that you might be able to spray in there might not last as long as the old-fashioned stuff.

[Dsanduril]

They look like they are for wire rope halyards (particularly the darker one to the right in your photo). The left one looks like maybe the wire groove is just about worn away.

If they are wire sheaves and you are still using wire halyards then might keep them. The wire will tear up new ones reasonably quickly anyway. If you've switched to line halyards you and your halyards will appreciate replacing the sheaves with ones designed for whatever size rope you use.

[captjcook]

Look a bit crusty...I have similar sheaves. If the fit is too loose, bearing to axle pin, it can slice halyard or cause a jam. If you can replace pin at the same time...all the better. Garhauer has some sizes of better design.

The bronze bushings can be replaced...I got mine for about $2-3 ea. Essentra Components, used to be Reid supply.
You can have yours re-hard coat anodized...Think I paid $17 ea. If you go this route...the bushing bore needs to be masked (like plastic pin) as acid is used to remove old anodizing and bushing will be loose.

Rig-Rite wanted $100 each for new sheave.

Feeling that price highway robbery, I spent hours turning my own...look just like the ones you have lightening holes and all only new...I can be so hardheaded. I did groove for line only.


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[Alan Mighty]

Looks like you have masthead sheaves and axle pin designed for low velocity use, i.e. a cruiser rather than a racer.


Does each sheave have an integral bushing sleeve, such as bronze, that contacts what looks like a stainless steel axle pin?


Hard to believe a sheave is 100% Al in contact with ss.


I would suggest:

1. Routine maintenance (which seems to have been lacking), while the mast is vertical and the sheaves and axle pin are in the masthead box:
* remove salt crystals and dust
* spray lubricant


2. Infrequent maintenance (when the sheaves and axle pin are removed from the masthead box, a job easily done when the mast is horizontal and, depending on the nature of your masthead box, only done with care when the mast is vertical):
* thoroughly clean sheaves
* inspect sheaves including the bushing
* inspect axle pin, looking for wear ridges and grooves
* thorough lubrication of the axle pin/sheave interface.


With plain bearings (such as bronze/brass bushing on a stainless steel axle pin) in a situation with low velocity halyards, I prefer a grease mixture to deliver lubrication and to stay in place. I use a mix of anhydrous lanolin (brand names such as Lanocote, Lanotec) and a white lithium grease.


You should also be able to find aerosol can versions of both anhydrous lanolin and white lithium grease. That means routine maintenance can be done with a seasonal trip to the masthead, clean the sheaves, followed by quick squirts of spray Lanotec and white lithium grease. Less frequent maintenance depends on your schedule for unstepping the mast (which may vary from once a year to once or twice a decade), when you do a more thorough job of smearing lanolin and white lithium grease on the axle pin and inspect the bushing sleeves.

[Stumble]

Call zephyr works and get some new delrin sheaves. The wire one needs to be replaced anyway, and the amount of time it will take to really clean those properly isn't worth it.

[allanbranch]

Thanks for all the wisdom!

[Rustic Charm]

What is the wire one used for?

I have twin rope ones.

[captjcook]

Back in the day cordage stretched...a lot. Halyards were wire spliced to a tail of line. If made to proper length, the wire was wrapped on the winch and line cleated off...Hence wire/rope halyards.


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[hamburking]

Originally Posted by Dsanduril

They look like they are for wire rope halyards (particularly the darker one to the right in your photo). The left one looks like maybe the wire groove is just about worn away.

If they are wire sheaves and you are still using wire halyards then might keep them. The wire will tear up new ones reasonably quickly anyway. If you've switched to line halyards you and your halyards will appreciate replacing the sheaves with ones designed for whatever size rope you use.

You beat me to it...that upper one in the picture looks like a wire/rope sheave. Some riggers will "turn" the sheave, so that it can take all rope instead. If you still have wire and rope halyards, its a good time to switch to a new all rope halyard.

[Ribbit]

Motorcycle drive chain spray grease might work well for the bearings. That stuff penetrates well and sticks.

It's pretty cheap too (unless in Andorra, where they sell really expensive ceramic stuff which is useless and doesn't last long).

You don't have to get a mucky black traditional one, the clear equivalent is just as good.

It's probably good for furler bearings too.

[Cheechako]

Some are frozen on the shafts. Make sure the bores and shafts are very clean. Aluminum on SS is good for freezing up, are those bushed? Bronze bushings are easy to get and might be a good upgrade if possible. what would you'all lube them with?

[captjcook]

Look closely at the single sheave pic...you can see the bushing...I use a Teflon grease since it is "up there". I like Ribbit's idea of spray grease for the furler though, My Furlex has a rather inaccessible upper spindle bearing...might just work...


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[Wind River]

There is no way to remove my main mast sheeves with out un-stepping the mast and removing the mast head. There is no way to get grease to the sheeve either.
So while my masts are down, I am having a small hole center drilled from the end of shaft on each side and then cross drilled to each sheeve. I'll install a grease fitting at the end of each side of the shaft.

Viola!, grease-able sheeves.

[UNCIVILIZED]

With sheaves, you want to use better materials, & design from the outset. So that little to no lubrication is needed. As it tends to attract salt & grit, which increases friction, & accelerates wear, etc.

You can go with sheaves that have fixed, integral bushings. Onew which are made from materials which act as their own bushings. Or sheaves with their own bearings, built in.

If you want to keep the ones which you have. Clean them up, & polish both the shaft, & the shaft holes inside of the blocks.
Sometimes just a 3M Scotchbrite pad does the trick, & for others, a bit of machine oil, on some fine, wet-dry sandpaper is what's needed.