cutting into skins

[prkaye]

What are some methods for cutting rectungular holes, or other odd-shaped holes, into a skin, or other piece of sheet metal? I suspect a jig-saw would probably rip it to shreds.

[Mel]

Phil,
I use a cutoff wheel in a Dremel. Drill a hole at each corner to give a radius first. Practice on scrap. These wheels won't take ANY side loads. Once you get it down, they're a easy to master. WEAR EYE PROTECTION!

[Jamie]

Hi Phil:

For making the rectangular cutouts on my instrument panel (stock Van's 0.063) I used a jigsaw with no problems whatsoever. Just be sure to use a high tpi (teeth per inch) metal cutting blade.

For thinner material I like to use my Dremel tool with a cutoff wheel. I've also used a cut-off wheel in my pneumatic cut-off tool for making some cuts. Regardless of what you use you're going to end up doing a lot of filing to final shape.

For smaller rectangular holes (like the baggage bulkhead cutout for my ELT remote) I like to use #30 bits in the corners of the rectangle. Then I will use a uni-bit to remove as many large holes in the center of the cutout as possible. Next I use a Dremel cutting bit (similar to this one) to remove the remainder, then file and scotch-brite.

Hope that helps,

[Rick6a]

Originally Posted by prkaye

What are some methods for cutting rectungular holes, or other odd-shaped holes, into a skin, or other piece of sheet metal? ....

A few days ago, I cut in a hole to accept a Gretz pitot mast. First, I used a Unibit to remove most of the material from the hole. That was followed by more material removal using a small cutoff disk fitted to a Dremel-like pneumatic pencil grinder and finally edge finished using a small rotary file fitted to the same tool. I pretty much use the same technique for cutting in all odd-shaped holes.

[prkaye]

Will a cutoff wheel work in my die-grinder? I've never used one before... is there a particular size/shape/type that I should get. Then do I use it basically like a circular saw?
I'm thinking right now about hte holes in my leading edges for my duckworks lights.

[Mel]

You can use a die grinder. Use the larger cutoff wheel that Van supplies for cutting the canopy. Just make sure that the wheel is designed for the speed of the die grinder. WEAR EYE PROTECTION!

[Ironflight]

I've used both a Dremel and a die-grinder with their respective cut-off wheels for this kind of job, and unless the hole is really small, I prefer the die grinder. As Mel said, the Dremel cut-off wheels are very fragile when it comes to side loading - I've busted bunches of them. Larger cut-off disks are generally better reinforced. But fit the size of the tool to the size of the job.

Paul

[RV7Guy]

As others have noted, the Dremel works great. I have a metal cut off wheel with abrasive edge that I now use for cut off use. No worry of the disk coming apart.

The metal disk is thinner and will allow you to get closer to the line. It also cuts much smoother and will reduce your filing time.

[Sam Buchanan]

the Dremel cut-off wheels are very fragile when it comes to side loading - I've busted bunches of them.

There are at least two types of cutoff wheels available for the Dremel. The thinnest ones are indeed very fragile and grenade with little provocation. There is another fiber-reinforced disk that is much more durable and the kerf is only a little larger. But these disks can tolerate more abuse and are much more practical to use. Both are used with the same mandrel.

And has been stated---Wear Eye Protection!

[Davepar]

I've found this little Dremel attachment to be very handy for cleaning up the edges after the initial cutting.



It can do some serious damage if it gets loose, so practice on some scrap first.

Dave