Cough cough... Turin your sizes are a tad out..
The common ones are (skin pins are the same as gripper pins)
The red gripper pins are 3/32 in size
The yellow gripper pins are 1/8 in size
The blue ones are 5/32 in size
The black ones are 3/16 in size
There are also 7/64 which is brown, 7/32 which is green and 1/4 which is white.
You also have cleco pins that do the same thing but are anodised, see
http://www.skinpins.com/catalog/prod...leco-type-p-19
Basically you drill your rivet holes to the sizes mentioned above, the pins slot through and is used to pull the skins together and hold it while drilling other holes, you then use it to hold the skins while rivetting it together, it consists of two legs that add up to the diameter of the hole, one leg which is longer moves up and down in the middle and has a knurled nut on to tighten it, it also has a bulge on the other end, so when you pull that leg through and tighten it, it increases the diameter along with the other leg, so grips the skins together, does that make sense?
Rivet colours see
http://forum.keypublishing.com/showt...gnesium-rivets
.