Winch fasteners...

[atmarineservices]

Hi All, just in the process of moving my mast mounted wich on a delrin pad. The pad was installed backwards, causing the halyard toride up onto itself. No big deal, remove (stripped) fasteners and move to propr location and drill for rivnuts. After drilling for the rivnuts, I failed tt take into account the curved mast section, and the outer most fasteners will not line up. One did gall, and needs to be delt with tomorrow. Is it accecptable to use silicone bronze flat heads for a winch mount? The spar is aluminium, and tefgel will be standard. I say bronze beccause it has more flex that SS. I was thinking this, along with slightly fileing the winch mount to get the flathead fasteners to go in at an angle. Good idea, or bad idea?
Option 2 is to have a winch pad welded on this summer.
Any input?

[Douglas]

Currently, I am in process of installing bronze Muray halliard winches on my aluminum mast, but using Delrin plastic pads between the two, and using SS flathead machine screws, to secure them.

I am not sure just why you decide to use rivnuts, and not just thread the mast wall for your fasteners.

I guess that you are familiar with Heli-Coils, as if you had to redrill the fastener holes to a better angle, then insert the Heli-Coil to bring the thread size back to your original size ?

Nigel Calder's book says he doesn't like welding on the aluminum mast tube especially when that welding goes half way around the mast, like at a spreader base.

It is good that you are asking questions when you are not sure, and I have always liked Brion's words, "build in a reserve of neglect, when ever you can" ,,,, there is great wisdom in his words.

Douglas

[atmarineservices]

Thanks for the note. AFTER drilling and installing the rivnuts, I had thaught of the idea of a helicoil. Of course, this is after the rivnuts are installed, and misalighned. Isn't this the way it goes sometimes?
I am planning on leaving the rivnuts in at this point to keep the hole stout, and helicoil the oriunigial stripped 1/4-20 holes and use them. This winter, I will have a pad welded on.
Thanks!!

[Brion Toss]

Hi,
First, I think riv-nuts are better for this job than helicoils, because mast walls are so thin. There's just not enough thread length for happy helicoils. Unfortunately, your holes are in the wrong place, and you are talking about torturing the fasteners in -- hence the question about bronze. I am afraid that, no matter what you use, you'll end up with a bad job. Even if the fasteners can somehow go sideways, the mast is softer than them. You'll end up with stresses and deformations that you don't want, especially on something supporting a winch.
If I had made such a chuckleheaded mistake (and of course that has never happened) I would probably have an aluminum plate made for the area, significantly larger than the winch. I'd put it right over those misplaced holes, fastening it thoroughly, but not where the winch fasteners will go, and then tap the winch fasteners into it.
Really, don't sell yourself and your boat short by making a mistake worse.
Fair leads,
Brion Toss

[atmarineservices]

Thanks for the input Brion,
I had this idea also floatting around for a solution. As far as fastening this new curved alum plate to the mast, would you try to somehow use the old holes, or new holes with rivnuts somewhere, then let the winch fasteners go into the plate, and sit inside the old "ghost" holes where the wrong rivnuts are.

Would welding a pad on be a sound solution, or would you stick with the alum plate idea?
Thanks, and masthead is a beauty, too bad it is mostly out of sight!!

[Brion Toss]

Hi again,
I'm still with the screwed-on version, and in general try to avoid welds on masts. They can certainly be done, but it is tricky, which is why we so so many failures resulting from welds in spars.
Glad the masthead is good. I look forward to seeing photo's of you under way.
Fair leads,
Brion Toss