Scillypete
Well-Known Member
Planning on fitting some mast steps this winter, standard alloy mast, stainless steel steps, which will be best to secure them with, stainless self tappers or monel rivets?
Screws or Rivets
- Thread starter Scillypete
- Start date
JVL
Well-Known Member
You will doubless here arguments for both! I used stainless Allen socket screws and tapped the mast wall, all worked well !
John
John
Fr J Hackett
Well-Known Member
Monel rivets with duralac for good measure.
neil_s
Well-Known Member
The self tappers will leave a lot of sharp points poking into the interior of the mast. They might shred your halyards. A bit more trouble to do, but I'd prefer the monel rivets. Check, though, that your riveter can get to all the holes in the steps.
merlin3688
Well-Known Member
Another one for Monel rivets but make sure correct length, 3mm into section plus the thickness of step and mast, drill sizes for 3/16 rivets 4.9 and 1/4 rivets 6.5, correct size is possible 1/4" x 3/4" with dome head. at Sailspar when we used to fit stainless steps we used nylon washers under each step, this is far less messy then paste. Hope this helps.
NormanS
Well-Known Member
If you ever want to use the mast steps, definitely monel rivets. I made the steps for my mizzen, but bought folding ones for the main. I have to admit that the folding ones are less obtrusive. The bought ones were drilled for 5mm, but I drilled them out to 1/4", and used 1/4" rivets for extra security.
thinwater
Well-Known Member
What he said. There are very few times self-tappers are safe in a spar. If they don't get a rope, they will chafe a wire.
William_H
Well-Known Member
It is veery easy to tap a thread into the ali mast. Just buy the correct taper tap and screws. A battery drill with reverse can drive the tap in very quickly and easily with easy reverse. If you choose to use rivets you will need a powerful rivet puller. You might even consider buying or renting a pneumatic riveter. I have one and it is magic. olewill
Neeves
Well-Known Member
+1
Large rivets are very difficult to instal unless you have a powerful riveter and up a mast even more difficult from a bosuns chair (or whatever). The little hand riveters will be a waste of time - too small for mast steps.
Jonathan
fergie_mac66
Well-Known Member
Lidl had a hydraulic riviter for 18£ a small compressor 69 quid jobs done
NormanS
Well-Known Member
I first made steps for my mizzen, and hoped to fit them with the mast in situ, by drilling and tapping for s/s set screws. The relatively thin wall of the mast meant that I had no confidence in the screws, and abandoned the project until I was able to get the mast down and fix the steps properly with rivets. Agree that it would be very difficult to rivet with the mast up.
Scillypete
Well-Known Member
TVM for all the advice, rivets it is but not quite as easy as I assumed, these things never are
merlin3688
Well-Known Member
When you fit (Guessing the mast is down) fit the first one and site through this one to get all in line, some sections have an extrusion line which is in the centre of the mast which helps with lining up. Fit steps 18" apart on opposite sides, spreaders can be used as a step so you can work down from them. Fit two in line about 5' from the top as most of the work you need to do will be at the top of the mast. Hope this helps.
sunquest
Well-Known Member
How about Riv nuts or am talking out of my rear end
vyv_cox
Well-Known Member
Lots of people suggesting monel rivets. I am not sure why there is any necessity. It may not generally be known that pop rivets are produced in two principal grades, 1000 series, which is unalloyed, about 99% pure aluminium, and 5000 series, which is the marine grade. Professionals will use the 5000 series ones for mast work, where the mast will be anodic to the rivets, thus protecting the rivets themselves. These are widely available from many suppliers and will be perfectly adequate for this job. Monel rivets have their place where greater strength is required but their additional corrosion resistance is unjustified in most applications.
doug748
Well-Known Member
A very good point.
A lot of stuff on masts is vastly over specified. I have a jumper strut attachment loop that is fixed by six 1/4in monel rivets. Bonkers, crackers. Tricky to pull and expensive to boot. A weight engineer would have a wobbler.
It seems to be driven merely by custom and practice.
Here is some interesting data:
https://www.rgafasteners-psm.com/files/tech_data_rive_.pdf
NormanS
Well-Known Member
When I'm up my mast, I'm perfectly happy that my steps are attached strongly and securely, and couldn't care less if they are "over specified". 
vyv_cox
Well-Known Member
Fair enough but note that the data in the link has reservations about the corrosion of copper- nickel rivets in aluminium in marine environments. The strength of 5000 series aluminium rivets is well above what is needed.When I'm up my mast, I'm perfectly happy that my steps are attached strongly and securely, and couldn't care less if they are "over specified".
BelleSerene
Well-Known Member
Vyv, that is really useful. I can't find anything about the 5000 series rivets for a job myself (of metal cleats to alu mast). What are the 5000 series ones made of please - and is there another name used?
vyv_cox
Well-Known Member
They are shown in the link posted by doug748. Some manufacturers/sellers call one type 'aluminium' and the other 'aluminium alloy'. RS stock both, e.g. http://uk.rs-online.com/web/p/produ...670uozEYaiw7udS8ZT4aAox7EALw_wcB&gclsrc=aw.ds
