Localizing where to drill the hole.

[peter houpt]

Sometimes you need to drill a hole in the direction or position under your aluminium piece,which you cannot see. Plastic surgeons use a direction finder to fill tissue expanders through the skin. The direction finder localized a small magnet incorporated in the tissue expander. Tape a very small magnet under the aluminium skin and the direction finder shows you exactly were to drill your hole.

The direction finders are disposable. Every plastic surgeon can give one to you.

 

[JonJay]

A good buddy of mine invented a kit for the early RV’s that included a viewer and small round magnets. The magnets were adhered with super glue so they would pop off easily when drilled. These were used primary to locate rib centerlines or actual places to drill.
He sold a lot of them early on, but prepunched kits put an end to their need.
I could still see applications from time to time.

 

[P51Stang]

Here’s a technique I have used. You can buy very small magnets on Amazon along with something called “magnetic viewing film”. Tape the magnet into the underlying rivet hole, put the undrilled skin in place over the top and slowly move the magnetic film over the magnet. The dark spot is the magnet and identifies where to center punch the hole. Center punch all the holes and remove the skin to drill. I replaced a leading edge skin on a Piper with hurricane damage that lined up perfectly with all the existing wing rib rivet holes.