[BigLew18]

Recently, I serviced (for the first time) the two winches located on the mast (one on each side) that help with halyard tightening. Both are Lewmar 6's, and each has a plate under the winch that has a concave surface on one side to sit flush against the mast and flat surface on one side for the winch base. Each plate has one screw in the center to hold the plate to the mast, and six holes around the circumference to allow bolts from the winch plate to screw into the mast.

I removed all of the bolts to check for corrosion, serviced the winches, and reassembled. Now, all of the bolts that held the winches to the masts have backed out of the mast as I crank the winch to raise the mainsail, and the winches and bases are no longer attached.

I suspect that the reason they bolts held fast before was due to corrosion holding them in place, and that corrosion was broken when I removed the bolts. It now seems that the bolts are not biting well into the threading in the mast. Has anyone suffered this problem before; and if so, what would you recommend I do to solve the problem.

Thanks in advance for your advice.

 

[jzk]

Could you tap new holes with threads one size up?

 

[DonScribner]

Lew,

How about RivNuts? You oversize the holes by about 1/32, maybe 1/16, then insert the nuts from the outside. They are attached like pop-rivets with a special tool or they can be installed with a bolt and a wrench. They are tenacious little whelps; amazing in shear and pullout. And they come in several designer flavors, SS, aluminum and the like.

 

[Jaramaz]

Consider a usual ss nut, with lock-ring. Washers to speard the load.

Access has to be via the lower end of the mast, you may have to dismantle the foot.

Winches do carry high loads. Not fun if they do not work as they should.

/J

 

[MarkSF]

Drill the threads out and use rivets? McMaster Carr have high strength 1/4" rivets, 2400 lb rating.

 

[JonEisberg]

Couldn't you simply rotate the winch bases a bit, and drill and tap new holes in between the old ones? # 6 winches are pretty small, and as the loads will only be in shear, it shouldn't really be necessary to thru-bolt them, machine screws alone should suffice - at least until you perhaps lower the mast, and back them up with nuts...

Be sure to use Tef-Gel when threading the new machine screws, you'll be good to go...

 

[miatapaul]

If they seem to be holding when torquing them down I would try some medium strength lock tight. That may work.

 

[Gladrags1]

I second the recommendation for loc-tite! That will keep the screws that bite from backing out.

Tod

 

[Mechsmith]

Most Auto Parts stores stock "Heli Coils". I'd investigate those first. If you have a suitable place for them they are better than new. For instance they are used extensivly in aluminum cylinder heads.

You should also use some method of anti corrosion either "Never-Seize" or Thread Locker "Locktite is one brand name, Permatex also sells them both.

 

[Chas H]

If they seem to be holding when torquing them down I would try some medium strength lock tight. That may work.

I would try Loctite before drilling new holes. If the threads on the screws are damaged it would be a good idea to replace them also.

Loctite is available in different strengths and for various size threads. Look up specs before purchase.
-CH