Has Anyone Used Rawlnuts for Mast Fixings?

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Anwen

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I'm looking at replacing the clamcleat for my genoa halyard with a Spinlock clutch. The existing cleat is rivetted on, but the fixing holes in the base of the clutch are too recessed to get a rivetting tool in, so I'm looking at some kind of screw fixing. Given the potential problems with using some kind of stainless fixing direct into the mast, I'm wondering whether rubber Rawlnuts would work - they would provide isolation between the dissimilar metals of the stainless fixing screw and the aluminium mast, but I'm worried that they wont hold up well in use, and may be a bit wobbly.

Regards,
Jon
 
There must be billions of stainless fittings attached to aluminium masts and very few have any problems. I imagine that there are at least 50 on my boat alone. If you attach your fittings using chromate paste I don't imagine that you will have any concerns.

Conversely, I can't see Rawlnuts holding much of a load in sheet material.
 
Those look great. They look a great deal more practical than rivets for all sorts of circumstances . Could you use them to install a mast winch, do you think?
 
[ QUOTE ]
Could you use them to install a mast winch, do you think?

[/ QUOTE ]I'd imagine they have the same tensile/shear strength to similarly-sized rivets, so yes I suppose you could. Generally, rivetted fittings on masts seem to be the preferred solution.
 
I hadn't seen these before, they look very interesting.

Another option is Rivnuts, but I didn't suggest them earlier as they are quite expensive and the tool for setting them costs a lot more, so hardly worth the investment for two holes.
 
The reason I didn't use Rawlnuts for my new mast winch was that you drill an 8mm hole, in order to insert the rubber piece, then screw in a 3mm screw. I thought that, if/when the rubber perishes, or is distorted you are left with a 3mm screw in an 8mm hole! I stuck with rivets,using a s/s backing plate.
 
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You can 'pop' recessed rivets by sliding some spacers along the pin. Some spare nuts will do. Get ready to catch them when the rivet pops!

[/ QUOTE ]I agree - use the rivets and put some small nuts on the rivet to space the rivetting tool away from the fixing. Its what the rigger would do. I am not convinced about the strength of the other fixings mentioned in this context - but I could be wrong and will bow to others opinions.

The cheapest way is to use some small nuts as a spacer and rivet away...
 
Thanks for all the replies. I was looking for something like rivet nuts but couldn't remember what they were called. I managed to find some aluminium ones on e-bay at a good price - 80 assorted 4,5,6 and 8mm for 4.25 GBP. I think I should be able to set them with an allen head machine screw and a penny washer of the right size, using an allen key to pull it tight.

The fixing holes on the clutch are M6, and I know a monel rivet of this size is beyond the capacity of my hand pop riveter, so I need to use a screwed fixing. However the tip of using nuts or a roll pin as a spacer for the riveter is a gem.

Thanks again for all the help - much appreciated, and I'll let you know how I get on.

Regards, Jon
 
Hi, if you use a setscrew to pull up a rivnut, use a screw that is longer so that you can run a nut down against the washer while you hold the head of the setscrew. If you just use the screw against the washer, you will tend to strip the thread on an aluminium rivnut.

Peter
 
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