[Michael Burbidge]

I'm ready to install strobes/navigation lights in my fiberglass wingtips. I need to drill/cut a 1 1/2" and a 1" hole.

What tool should I use to cut these holes without chipping the fiberglass?

 

[Danny7]

probably the cheapest method would be to get a high rpm pencil grinder and some rotary carbide grinders and go to town at high speed.

i've seen the pencil grinder at harbor freight for something like 20 or 30$, pretty cheap. pencil grinder http://www.aerocraftparts.com/Categories.aspx?Category=409dd9af-6725-475f-a5bb-843f158a90b7

bit

http://www.aerocraftparts.com/ItemF...Category=09d97439-4e68-431d-81ca-76c5740e05e3

you can get cheaper bits, but perma grit is pretty nice.

 

[eric_marsh]

I think a conventional hole saw would be a good choice if the glass is in good shape and you go at it slowly.

 

[hydroguy2]

I like the Dremel diamond wheel for fine cuts in fiberglass. You can cut right next to your scribed line.

diamond wheel

 

[William Slaughter]

I cut mine with holesaws, then used a Dremel to smooth up the edges. No problem.

 

[samray]

I mark the hole with a sharpie, drill a series #40 holes about 1/16" away from the cut line, use a dremel tool cutoff wheel to finish the cut between the #40 holes, and finally sand back to the cutline with a dremel tool sanding band.

Sam Ray

 

[shuttle]

For curved cuts I find this works well:
Drill a hole or multiple holes then use an ordinary fret saw for the initial rough cut followed by filing and sanding to the final shape. Did my wingtip landing light cut outs and spinner prop cutouts recently this way.

The sanding drums/sanding bands that Avery sell work well, especially in a pillar drill if it suits the workpiece
http://www.averytools.com/pc-807-39-3m-rubber-expanding-sanding-drums.aspx

 

[alpinelakespilot2000]

If you want a perfectly round hole, just use a hole saw. Covering the fiberglass with masking tape would help with any chip out, although there shouldn't be much.

 

[Pilottonny]

Hole saw.

Hole saw, takes a few seconds, no chipping! You should have a "set" of various dimensions handy anyway, to make lighthening holes, etc.

Regards, Tonny.