How do i determine what size rivets?

weinie

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Sep 6, 2010
1,297
Jeanneau 349 port washington, ny
Need to replace a mast cleat that was previously riveted into the mast. How do I determine what size rivets to replace it with? Or should I just tap and use machine screws?
 

Joe

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Jun 1, 2004
7,999
Catalina 27 Mission Bay, San Diego
You could use your drill bit set to determine hole size, Check the specs on the various length rivets to determine appropriate depth.
 
Sep 8, 2014
2,551
Catalina 22 Swing Keel San Diego
It depends on the cleat and the load expected. If it is a low load cleat you can use AL rivets and not have dissimilar metal corrosion issues (as long as the cleat isn't stainless, so nylon or AL cleats). I avoid stainless rivets because you still have to tef-gel them anyway and they are a pain to drill out, so you'd be better just drilling and tapping for machine screws anyway. Higher load = stainless cleats properly isolated and SS machine screws.
BTW, I'm converting to lines led aft so I can eliminate the majority of the cleats on my masts... Yes, multiple masts. I picked up a few 'racing spares' from boats doomed for the scrap yard. My small nylon cleats will stay but those are only for small flag halyards or hoisting day-shapes. I'll use AL rivets on those.
 
Aug 16, 2009
1,000
Hunter 1986 H31 California Yacht Marina, Chula Vista, CA
Is everyone talking rivets or rivnuts? Wouldn't the latter be much stronger and more appropriate for a cleat? Could this be one of the rare instances where bedding with 5200 could be recommended?
 
Aug 1, 2011
3,972
Catalina 270 255 Wabamun. Welcome to the marina
5200 would be a lousy choice for that kind of application. The hole should not have enough clearance to get a bead of anything between the fastener and the mast.
 

capta

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Jun 4, 2009
4,766
Pearson 530 Admiralty Bay, Bequia SVG
Is everyone talking rivets or rivnuts? Wouldn't the latter be much stronger and more appropriate for a cleat? Could this be one of the rare instances where bedding with 5200 could be recommended?
I went absolutely gaga for Rivnuts when someone on another forum brought them to my attention! I even bought the tool. But after a bit more research, it seemed that the occasional one would spin, just not get tight enough, even with the very expensive hydraulic aircraft tool. That scared me off them, but perhaps with epoxy they would do the job better. 5200, I don't think would be strong enough in a twisting motion. So I'm going to get a few and give them a try with epoxy on something a lot less critical than a windgen mount. I can always go back and put some on the windgen mount later if I'm satisfied with my experiment.
 
Oct 24, 2010
2,405
Hunter 30 Everett, WA
Use aviation style rivets (Cherry rivets, not Pop rivets.) There are many high strength rivets available.
Yes they hold airplane wings on but they are decidedly different than what you will find in your local home improvement store. Go to an aviation place.

Don't use rivnuts for this application They aren't really strong, just convenient.
Ken
 

weinie

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Sep 6, 2010
1,297
Jeanneau 349 port washington, ny
Update:

I drilled out the old rivets. Turns out the holes are OVER 1/4 inches in diameter. That makes tapping and drilling for screws impossible as the next size screw is 5/16" which a) would require me to widen the cleat holes to the point where the strength of the (nylon) cleat would be compromised.

I ordered some 1/4" rivets and a rivet tool however the holes are recessed about 1.5cm into the cleat which makes using the tool impossible. How did they ever install these things at the factory?!?!?!
 
Sep 15, 2009
6,243
S2 9.2a Fairhope Al
Update:

I drilled out the old rivets. Turns out the holes are OVER 1/4 inches in diameter. That makes tapping and drilling for screws impossible as the next size screw is 5/16" which a) would require me to widen the cleat holes to the point where the strength of the (nylon) cleat would be compromised.

I ordered some 1/4" rivets and a rivet tool however the holes are recessed about 1.5cm into the cleat which makes using the tool impossible. How did they ever install these things at the factory?!?!?!
i think they make a countersunk head rivet for that....search Morson fasteners for them they also make a very good pop rivet gun
 

weinie

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Sep 6, 2010
1,297
Jeanneau 349 port washington, ny
i think they make a countersunk head rivet for that....search Morson fasteners for them they also make a very good pop rivet gun
I think the factory may have used a special rivet tool with a small diameter (less than 1/2").
I guess I'm going to have to tap new holes in the mast but I'd hate having the 2 old holes still present.
 

capta

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Jun 4, 2009
4,766
Pearson 530 Admiralty Bay, Bequia SVG
I obviously can't see what you've got, but it might just be better to plug these holes and relocate the cleat and do new ones. Is enlarging the old holes better than having the correct size holes in a slightly different place?
 
Mar 20, 2012
3,983
Cal 34-III, MacGregor 25 Salem, Oregon
It the cleat is held on with pop rivits, its obviously not a high strain attachment, so You could probably move the cleat one way or the other just a little and drill new holes... hopefully you would only have two holes showing afterward that could have a pop rivit installed just to cover/fill it...

The rivnuts are just a bad idea to be used on a boat. They just arent dependable enough and will be messy and time consuming when one fails, and it WILL... and when attached to aluminum, even if it is installed good, they are STILL dis-similar metals which will set off another problem that will have ro be addressd later, so the messy removal process and repair is only being postponed.

When using stainless screws or self tapping hardware, you can drill an under sized hole and still get the screw in easy with a tighter and better holding thread if you ALWAYS remember to use either a nickle/marine antiseize compound or lanacote on the screw threads when inserting it in the first time...
its amazing how easy a stainless screw will cut threads in aluminum when it has the proper lubrication...
never install a screw or bolt in aluminum without some sort of lube... the same with pop rivets.
 
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weinie

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Sep 6, 2010
1,297
Jeanneau 349 port washington, ny
Ill probably just relocate the cleat. At this point im just curious if there was some riveting tool or technique i wasnt aware of.
 
Jun 8, 2004
10,024
-na -NA Anywhere USA
I have seen manufactures on masts where strength is needed using stainless steel pop rivets vs. aluminum and you will need the heavier pop rivet gun vs. the one you can buy for a home mechanic.
 

weinie

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Sep 6, 2010
1,297
Jeanneau 349 port washington, ny
I have seen manufactures on masts where strength is needed using stainless steel pop rivets vs. aluminum and you will need the heavier pop rivet gun vs. the one you can buy for a home mechanic.
I got a pretty heavy duty one off amazon along with some 1/4" stainless steel rivets from fastenal thinking this would be a quick repair.
 
Mar 20, 2012
3,983
Cal 34-III, MacGregor 25 Salem, Oregon
The problem is that tip is too fat to fit into the countersunk hole (maybe 1/2") to drive the rivet.
I took one of my rivet gun tips to the grinder and tapered it so it would recess in with the head of the rivet... there is more metal in them than is necessary to do the install job, but they need it there to make a place for the wrench to fit so they can be changed out easily.

you can buy replacement tips for a quality installation tool, so dont be afraid to customize what you got so you can complete the job.