Cut hole for pitot mast in bottom outer skin, left side. Used a unibit and then finished grinding edge w/ Dremel tool and various bits. Inserted mast through skin and match drilled attach holes. Checked alignment w/ spar and found inboard side of mast base overlapped w/ wing rib. So I used the bench grinder to shave off less than 1/16" from inboard side of base plate and polished w/ scotchbrite wheel. Countersunk mast base holes that will lie under dimpled skin and deburred other holes. Then cleaned mast inside and out w/ heavy duty degreaser and scotchbrite pad. Dried and then primed inside and out with SEM.
