Rivnuts: who has experience?

All,

I got some monel rivnuts to re-mount two padeyes on my carbon fibre masts. The padeyes support the choker lines of the wishbones. On the mainmast with 11 mm walll thickness, I drilled and tapped thread for 8 mm bolts. That works fine. On the original Freedom mizzen with its 7 mm walls, the bolts come loose so I want to use monel rivnuts. I’ve got special ones for tube (reduced head) and for plastic (ribbed body to provide more grip).

Because I only need to do 4 rivnuts, I don’t like to buy a special tool to mount the rivnut in the mast.
Has anybody experience with using a simple bolt with a nut that you tighten against the rivnut to create the collar? Is that going to work? Will it work on 8 mm rivnuts or only on the smaller 6 mm (1/4") rivnuts?

Thanks,
Michel
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Gday Michel,
I have a rivnut tool if you need it, the only problem is getting it to you. Let me know if you want it and I’ll get a 8mm mandrel for it (my company sell them and I needed one to fix a problem with disimilar metals between my boom and the stainless bolts holding my vang in place).
I haven’t heard of anyone doing it the way you are talking about, but I don’t see any reason why it wouldn’t work. I’d probably try a test first.
Cya
Marno

Hello Marno,

Much obliged for your offer. I’m going to di a test first on a piece of sewage tube to see how the rivnut collar inside the tube is going to be. And I’m going to find out the cost of the tool and the mandrels for 6 and 8 mm rivnuts. If that’s more than postage from and to UK, I probably take your offer to use your tool.

I think that this might be what you’re looking for

http://www.fjr1300.info/howto/rivnut-tool.html

Then again, why not simply drill and tap your mast instead of using a rivnut? I would have thought that 7mm would have been enough material.

– Geoff

Geoff, super! Indeed exactly what I need! A lowcostrivnuttool (3x wordvalue scrabble word!). I am a bit surprised too that the 7 or 8 mm walls don’t hold the 8 mm bolts, but it is an unfortunate fact.

Thanks for your great help!