Monel pop rivets

[cagey]

How do you size pop rivets in particular the male bit that gets squeezed and distorts. I’m riveting mast steps to a 30yo selden mast, the rivet dia is given but I don’t know how much to allow for inside the mast. The step flange thickness including isolating washer is about but less than 2mm.
Thanks
Keith

 

[lw395]

https://www.rivetwise.co.uk/product...ype=standard-open-rivets-1&rivetBodyMat=Monel

The nominal length of the rivet wants to be at least 3mm more than the total gauge of metal it's riveting, more in bigger sizes.