Best method to make matched holes

[Larry Korona]

Looking for advice on how to make matching holes in a replacement fairing on my Cessna's elevator.

 

[Doc Holliday]

You need a hole finder

https://www.amazon.com/Air-Capital-...hvlocphy=&hvtargid=pla-4584276309390610&psc=1

 

[PaulS]

These would be useful.

Jongdari 24PCS Dowel Centering Pins for Woodworking, Steel Drill Center for Dowel and Tenon Center Transfer Plugs Point (1/4", 5/16", 3/8", 1/2"): Amazon.com: Industrial & Scientific

 

[Larry Korona]

Thanks for your help! I'll give them a try.

 

[Bacho]

The hole finders Doc posted are the right tools for this job.

 

[Let'sgoflying!]

You need a hole finder

which can be fabricated with scrap metal and a few rivets in about 15 minutes, for the diyer

 

[nrpetersen]

Or, a sheet of drafting Mylar. It is transparent, dimensionally very stable yet will smoothly take the markings on the "rough" side from a hard pencil. As long as the replacement part is simple sheet with simple bends, and not compound formed, I find it to very useful for creating a new part.

 

[Ed Haywood]

Best method is to clamp in place for the install, and match drill holes in the new piece through the existing holes in the base material. Of course that depends on access to the holes, and the relative softness of the materials. If the base material is softer than the new material, and thinner than the height of the bit point, you risk elongating the existing holes.

 

[Let'sgoflying!]

So for a new wingtip fairing, you’d put the new one inside the old one and mark the holes?
Can’t see that working.

 

[Silvaire]

The hole finders are more than just locators they are also hardened steel drill guides which provide for an exact hole match.

 

[Timbeck2]

In addition to the hole guide aka strap duplicator you’ll need several clecos to line things up as you drill

 

[Magman]

In some areas where hole finders will not work yet another method is available.

IF it is a machine thread.

Cut/grind the head off of the screw.

Grind a point on the end of the screw.

Insert screw into nut plate with the point up and slightly above the surface.

Position the fairing in place.

Tap the fairing with a small hammer at the fastener .

The resulting mark will accurately mark where to drill.

 

[Timinfla2]

Centering Pins for life.

 

[Mooney Fan]

Depending ... drift punch

 

[Darryl Snover]

X marks the spot. Before you take the old one off, put two pieces of masking tape on the control surface pointing to each screw/hole, and then use a ruler to mark lines that if followed, will intersect at the center of the screw hole. When you put the new fairing in place, use a ruler to extend the lines onto the new part, and where they intersect is the right spot.

 

[Magman]

Good point to use tape.

No graphite on aluminum.