"Bruce E Butts" wrote in message
...

Mike,
Veeduber recommends that one drill with a #40, deburr and then dimple
with the 1/8" dimple dies. I have done some like that and some using
the #30 drill first. Sometimes I have to 'open up' the hole a bit with
a reamer when trying to put in the rivet when I use the #40 bit first.
Veeduber's advise was in reference to using blind rivets iirc.

The springback dimple dies are meant for dimpling fuel tank skins so
that smearing sealant will not make the rivet stand proud of the dimple
so I think they may be a few thousandths oversize.

Hope this helps and remember all advice is worth what you paid for it!
Bruce

Be careful using a 1/8" dimple die in a #40 hole. The aluminum can develop
radial cracks around the hole as the dimple die is forced into the smaller
hole. Check on scrap, first, obviously, but I suspect it is a function of
thickness as well as material (e.g., 6061...).

Michael Pilla