Frozen Masthead Sheave Pin

[EricHasAnEricson]

Hi all.

I have my mast down, and want to take advantage of the opportunity to replace the masthead sheaves with some new ones from Zephyrwerks. The situation however, is pretty dire. I have the Kenyon slide-in sheave pins that are welded to a plate, in theory you unscrew the plate and pull the sheave pin out. Bimetal corrosion has made other plans for me, as the pin has sheared off the plate (see photo), and it seems the aluminum has corroded the pin tightly into place.

I was thinking I could drill a hole through the opposite side of the mast and tap the pin out that way. Has anyone done this before? Any gotchas I should look out for?

Thanks.

 

[Afrakes]

Try to drill through the frozen pin with increasing sized drill bits. I know that it will be difficult getting the first drill bit started. Try using a very sharpened center punch to help. Start with as small a drill bit as you can. Have a local welding shop connect a replacement shaft to the mounting plate. You're going to replace the sheave, so it doesn't matter if you drill a bit off center.

 

[EricHasAnEricson]

Is that pin stainless? That sounds like a real operation if it is.

 

[Afrakes]

Is that pin stainless? That sounds like a real operation if it is.

Go slow and use plenty of lubricant. Lock the sheave if it begins to move.

 

[Pete the Cat]

I am skeptical of drilling the pin. Have you tried heat? You need at least Mapgas if not acetylene and, depending on what the actual sheave is made (hopefully metal) might not be the right process, but it is standard for removing stuff on a mast. Also, tapping it with a punch--from either side to loosen things. Is the other side entirely closed? I think your original proposal would be OK if heat does not work. Just a question: were you having issues with your sheaves? Seems like keel dropping and sheave replacement are becoming the new blister fixing-- but sometimes there is a reason for it. The 42 year old sheaves in my Tartan work just fine--I have lubricated them when the opportunity presents itself, but I am always curious about the motivations of others.

 

[EricHasAnEricson]

The sheave material appears to be plastic, but I could be wrong. Once I get it heated up, I don't have much to pull it out by either, just that little nub you see in the picture. If I do drill through the other side and there is nothing else there to get in my way, I'm tempted to lengthen the sheave pin hole so goes all the way through the mast, and replace the existing pin with a rigging pin, held in place with a pair of cotter rings. In my mind, that would be a simple, robust setup.

As for my motivation, no it's not strictly needed, but the existing sheaves are definitely tired, especially the one for raising the mainsail. I was surprised by how much friction it had when I pulled the main halyard up before dropping the mast.

As long as the mast is off the boat, it seems like a nice opportunity to get the big maintenance tickets out of the way. A new set of sheaves is not very expensive.

 

[Afrakes]

Not everybody has access to Mapgas or an oxy-acyt torch. Most folks do though have access to a drill motor and bits. If the sheave is plastic, which I highly doubt, all heat is going to do is melt the sheave. Not having any way to actually grab the end of the broken shaft complicates things. Have you tried spraying the sheave and shaft with Kroil or some like product to loosen the pin? Try a bit of finesse before breaking out the hammer.

 

[bgary]

I was thinking I could drill a hole through the opposite side of the mast and tap the pin out that way. Has anyone done this before? Any gotchas I should look out for?

Yes.

And it worked. The hardest part was convincing myself I was drilling in the right place. Actually punching them out was easy.

Saga here: https://ericsonyachts.org/ie/ubs/time-is-fluid-mast-re-hab-part-2-of-3.403/

I think I used a 1/8" bit, and a steel punch. Didn't take a lot of effort to get them moving.

(note, this is the way Buzz Ballenger recommended doing it. I don't think heat would have accomplished anything, JMO, other than perhaps damaging the aluminum "box" the sheave-pins ride within)

 

[EricHasAnEricson]

Yes.

And it worked. The hardest part was convincing myself I was drilling in the right place. Actually punching them out was easy.

Saga here: https://ericsonyachts.org/ie/ubs/time-is-fluid-mast-re-hab-part-2-of-3.403/

I think I used a 1/8" bit, and a steel punch. Didn't take a lot of effort to get them moving.

(note, this is the way Buzz Ballenger recommended doing it. I don't think heat would have accomplished anything, JMO, other than perhaps damaging the aluminum "box" the sheave-pins ride within)

Fantastic write up, thank you for sharing. I thought I'd done an exhaustive search of this site - I guess not.

Did you run into any issues pulling out that mast track? Mine looks pretty frozen in place, but I'm motivated to get better access to the wiring conduit.

 

[Christian Williams]

I thought I'd done an exhaustive search

The site relies to some extent on memory referrals, despite the efforts to make every issue easily searchable.

The good news is that this thread now contains the link to Bruce's blog, and his experience will be easier to find for the next guy.

 

[Loren Beach]

About that "darned" wiring conduit. When we had the spar down for 10 months during our re-fit. I had the original pvc tube pulled out. Most of the securing rivets had broken over the years and the tube had been banging around inside. Also, what with instrument cabling and vhf coax, it was really crowded with the original 12 volt wiring to both the steaming light/deck fixture and also to the anchor light at the top.
I replaced the single tube with two pvc tubes, riveted into place side by side. Now one carries the wiring to the lower combo fixture, and the other one carries all the wiring to the masthead. Now the mast is silent when the boat rolls. FWIW, our Kenyon spar is probably identical to the rig on the late model E-34/2.

 

[bgary]

Did you run into any issues pulling out that mast track?

Yes... but only because I'm not very smart

My mast-track (32-III) is in two-sections: above the deck, with the groove for mainsail luff grooves, and then a flat cosmetic piece below the deck. When I had the mast out I found that I could wiggle the upper piece in its slot (i.e., it moved freely) but I could not get the lower piece to budge. It was solidly in place. Very frustrating, and no idea how to get it free without powertools, flames, brute-force, etc.

Long story short... there was a small machine-screw at the very bottom of the mast that was only accessible from *inside* the mast, which locked that lower section into place. Removing that screw freed up the whole thing.

Bruce

 

[bgary]

link to Bruce's blog

Thanks! I just realized that the link I posted above was to the second chapter of the saga, and it is the first part that contains the punching-out-the-pins stuff. For posterity, here is the right section.

E32-3 - Time is Fluid ** (mast re-hab, part 1 of 3)

(**) "Time is fluid, so the moments where everything feels perfect pass in a wink, and those where you're on your knees in despair drag on like the death of a thousand cuts" ....Ann Aguirre In other words, "how a small job becomes a four-month...

ericsonyachts.org

 

[EricHasAnEricson]

I had some pretty bad aim getting at the pins from the blind side, but with some sweat and cursing managed to get all 4 sheaves out.

I extended the 1/2 inch pin holes all the way through the mast. I'll be securing the new sheaves with rigging pins, cotter rings on each end of the rigging pin.

I'll likely grease up the pins, and then seal the oblong end of the hole with an epoxy putty.

 

[bgary]

I had some pretty bad aim getting at the pins from the blind side

To the extent it might help the next EYO'r, the approach that worked for me was...

1) apply a strip of tape that runs from a known-good point on one side (e.g., edge of mast-track, face of mast crane), centered vertically over the original hole and extending around the front of the mast to the equivalent point on the other side. Keep it as level and true as possible. Oh, and use non-stretchy tape.

2) once sure that the tape-line is level and true, apply additional lines of tape edge-to-edge immediately above and below it for reference. Then use a sharpie to trace the outline of the original hole on that center strip of tape

3) pull that strip of tape and reverse it - lining it up carefully with your known-good points and reference tape-lines - so that the outline of the original hole is now positioned on the other side of the mast.

If you drill a small hole through the middle of that outline, it should be pretty close to centered on the pin.



$.02
Bruce

 

[G Kiba]

One word. Tefgel. On all stainless that you would like to remove in the near and far future.

 

[Chschaus]

Hi all.

I have my mast down, and want to take advantage of the opportunity to replace the masthead sheaves with some new ones from Zephyrwerks. The situation however, is pretty dire. I have the Kenyon slide-in sheave pins that are welded to a plate, in theory you unscrew the plate and pull the sheave pin out. Bimetal corrosion has made other plans for me, as the pin has sheared off the plate (see photo), and it seems the aluminum has corroded the pin tightly into place.

I was thinking I could drill a hole through the opposite side of the mast and tap the pin out that way. Has anyone done this before? Any gotchas I should look out for?

Thanks.

I had the same issue last season, I drilled ( as small as possible ) through the opposite side of the mast and used a punch to free the pin.
Then used a small ss screw to fill the hole after. The new pins from Zephyr didn't attach to the plate like the old ones so I made new plates with double screws to insure the pin couldn't back out. bgary's post is what gave me the confidence to do it. Thanks Gary if I forgot to thank you last year!

 

[EricHasAnEricson]

To the extent it might help the next EYO'r, the approach that worked for me was...

1) apply a strip of tape that runs from a known-good point on one side (e.g., edge of mast-track, face of mast crane), centered vertically over the original hole and extending around the front of the mast to the equivalent point on the other side. Keep it as level and true as possible. Oh, and use non-stretchy tape.

2) once sure that the tape-line is level and true, apply additional lines of tape edge-to-edge immediately above and below it for reference. Then use a sharpie to trace the outline of the original hole on that center strip of tape

3) pull that strip of tape and reverse it - lining it up carefully with your known-good points and reference tape-lines - so that the outline of the original hole is now positioned on the other side of the mast.

If you drill a small hole through the middle of that outline, it should be pretty close to centered on the pin.

View attachment 50592

$.02
Bruce

This solution is elegant in its simplicity. Wish I'd thought of it!