Carriage Bolt sleeve(?) for dissimilar metals(??)

[Ocean Girl]

We removed the windlass to cut a hawsepipe hole for our 3/8 chain. Our Seatiger 555 have these sleeves, liners, inside the four bolt holes on the windlass. I'm not sure what they are called. But they need replacing, if I want to replicate what PO has done.
The only purpose we can think of is for dissimilar metal interaction.
Thanks for any input
Erika

[skipmac]

My S-L windlass has an aluminum body so assume the same with yours. Bolts are stainless steel and it is good to separate the two metals. Over time the Al will be eaten away like a zinc anode. First the paint will bubble around the bolt, then flake off and the Al will start turning into white powder. If the SS bolt is threaded into Al the two parts will eventually weld themselves together.

[Dsanduril]

Looks like a delrin or possibly nylon bolt sleeve, and yes, I would presume for protection between dissimilar metals. You can try McMaster, but will need the dimensions. If the ones in the catalog are too long they're easy to cut shorter, but getting the diameters right is important.

McMaster-Carr

[Edit]

I see the McMaster page only goes up to 5/16" bolt diameter, which might be small on a windlass. Digi-Key, surprisingly has a pretty wide selection (and they'll sell four no problem). You can use the filters to select your exact dimensions and see what they might have:

Washers - Bushing, Shoulder | Hardware, Fasteners, Accessories | DigiKey

[/Edit]

[model 10]

If I needed those I would trot down to ACE Hardware and get some nylon bushings/bearings and trim to length. If you wanted to be custom you could use bronze bearings instead of plastic.

[skipmac]

Originally Posted by Guy

If I needed those I would trot down to ACE Hardware and get some nylon bushings/bearings and trim to length. If you wanted to be custom you could use bronze bearings instead of plastic.

If this is an aluminum case on the windlass bronze would not be the best option. Copper or copper alloys are generally very incompatible with aluminum. Would probably be better just to stick with the SS.

[model 10]

Originally Posted by skipmac

If this is an aluminum case on the windlass bronze would not be the best option. Copper or copper alloys are generally very incompatible with aluminum. Would probably be better just to stick with the SS.

My bad, I should have said what kind of bronze. The kind they don't have at Ace.

[JPA Cate]

Hi, Ocean Girl,

Take one with you and go to a bolt shop, if they have them in the industrial area not too far from where you are. Phone first to see if they have bolt sleeves. They are pretty common to prevent galvanic corrosion, as suggested above. Whatever you buy, you will want that little flange on the top, or a nylon washer 'cause the head of the bolt needs isolation as well as the shaft.

Ann

[rwidman]

Originally Posted by Guy

If I needed those I would trot down to ACE Hardware and get some nylon bushings/bearings and trim to length. If you wanted to be custom you could use bronze bearings instead of plastic.

Lowes has sleeves like that. Another option is the plumbing department. Get the right sized plastic pipe or tubing and cut the lengths you need. PVC, CPVC, PEX, or reinforced vinyl.

[UNCIVILIZED]

Push come to shove, just find a small machine shop, & take all of your parts with you, along with whatever material you want your galvanic isolating sleeves mad out of.
In the span of an hour, or likely half that, the old guy in the back who's been there forever, will custom turn you a set on a lathe. Plus a couple of spares as well (this part being key).

My brain's a bit fried at the moment to recommend a material to have them made of, but keep in mind that it may see some significant compression loadings, particularly underneath of the bolts heads, or the shafts also if they're not trimmed perfectly to length.

Such items are commonly used on aluminum boats, to isolate the much more noble, keel bolts, from the aluminum structure of the hull. And to the best of my knowledge, they're just called isolators.

Oh, & it's common to machine "the washer" on top, as an integral part of the shaft of the isolator sleeve. If for naught else, than to prevent the sleeve from dropping out of the bottom of the hole while you're fiddling with all of the other bits.

Which reminds me. When you're mounting them & the windlass, the holes are going to need to be a tiny bit bigger, diameter wise, for the isolators (plus your bedding compound), as under the compressive forces from tightening the bolts, they'll expand slightly.

[Dsanduril]

A couple more options for you. Manufacturer:

Nylon Flanged Bearings On Bunting Bearings and Bronze LLC

If you look up "bearings" in the your local town you should be able to find a shop that will have some in stock, exact size may make it an order item.

MSC sells the Buntings (above) as well as Poly Hi and iglide (use the "brand" filter to limit):

Sleeve Bearings | MSCDirect.com

One caution, you really want to find a length that passes all the way through the foot of the windlass. If the bearing is slightly less depth than the windlass you'll end up with a pocket between the deck, the bearing, and the bolt that will hold salt water in a nice, hidden place.

If your windlass base is aluminum it wouldn't hurt (my opinion) to use a dab of No-Alox in the hole before you put in the bearing. This is used in the electrical industry to prevent corrosion between aluminum and copper conductors, but I find it has lots of uses in preventing corrosion on a boat. This link is to Home Depot (because it is easy to find on the web) but you should be able to find some at any hardware store or electrical supply house:

Ideal NOALOX 4 oz. Anti-Oxidant Compound-30-026 at The Home Depot

[Cheechako]

flanged nylon bushings. Should be readily available.

[skipmac]

Originally Posted by Guy

My bad, I should have said what kind of bronze. The kind they don't have at Ace.

You must have a better Ace Hardware than any around here. All the local ones sell is cheap brass.

If you look at standard aluminum alloys and silicon bronze or manganese bronze there is at least 0.4-0.5 V potential difference. Even aluminum bronze alloy which is fairly rare, there is min 0.35 V difference. All higher than is recommended for compatibility, especially in a marine environment.

[Jim Cate]

OG, there is no need to worry about exotic materials here. The originals, which were almost certainly Delrin or a similar plastic, have lasted for many years. New ones of Delrin or Nylon will do equally well. This is not a difficult task... but do not fail to put something in those holes, for isolation is very necessary.

Jim

[bsurvey]

get some delrin UHMW or G 10 and machine your own this types of materials are easy to work with and will do the job do not use nylon as salt and sun deteriorate it

[model 10]

Originally Posted by skipmac

You must have a better Ace Hardware than any around here. All the local ones sell is cheap brass.

If you look at standard aluminum alloys and silicon bronze or manganese bronze there is at least 0.4-0.5 V potential difference. Even aluminum bronze alloy which is fairly rare, there is min 0.35 V difference. All higher than is recommended for compatibility, especially in a marine environment.

This is a great example of how aviation and marine applications differ. Aircraft have bronze bushings in aluminum from stem to stern.
The bushings and bearings at the local Ace are not brass.