How to open up a panel hole from 2-1/8" to 2-1/4"?

[sibriggs]

It seems to me the only real practical solution is a hole punch. I just helped another owner with replacing a compass panel hole with a hole for a G5.

If you are working on a panel with instruments and radios installed, you really don't want the vibrations and aluminum chips and dust flying around from any file or dremel tools.

A hole punch gives a clean precise hole and you smooth the edges with 220 or 320 after the process.

[deene]

Simple...use a 2 1/8 hole saw to cut 2 plugs out of MDF, screw/glue the two plugs together, slide plugs on your 2 1/4 hole saw and cut away.

Plugs act as pilot to center the 2 1/4 saw...

[Raymo]

2 1/8 hole saw inside a 2 1/4 hole saw.

[TASEsq]

Originally Posted by parabuzzle

This is also an option if you want to go the holesaw route:

https://www.youtube.com/watch?v=9-pBlZa1RBI

Basically it would be the 2-1/8" holesaw nested in the 2-1/4" one so the smaller one is the guide for the bigger one.

“Embiggen” is now my new **favourite** word.

[flyvansrv7]

accurately mark the desired diameter with a fine sharpie, also tape if desired just outside of your diameter line. Use a die grinder with 3/8" dia cylindrical carbide burr and use the method described above by n82rb and creep up on the line. You can use the carbide burr or the sanding drum, I like the carbide burrs because they last a long time on AL and are fast. Then use a die grinder with the 1" dia scotchbrite drum to smooth and deburr. Using the carbide burr it will only take a couple minutes tops to enlarge your hole.

If the panel is in the plane and your'e doing the above secure your powerful shop vac nozzle right behind your hole if possible or in front and you will have very little mess from the filings. The filings from the carbide burrs are very fine. I have used two shop vac's in spots where I really don't want the filings.

[RVDan]

Here is a technique that I have used when removing the panel wasn?t practical. You can get a 2? drum sander. Home Depot, Lowes or Amazon. Mark the hole as others have suggested and use the drum sander, moving it around the inside of the existing hole until you get to the desired diameter. I use a dial caliper to keep gaging the hole and can get a pretty round hole within .005? of the desired diameter. The grit size should be something like 60 to make quick progress. Maybe finer as you approach the finish hole size. Since the drum is nearly the same diameter as the desired hole it will be easy to keep it pretty round. Good luck.

[fixnflyguy]

Exactly what I would do, and have done many times. If your panel has access behind it, stuff some rags in there to catch dust,or tape a plastic cup behind it. and if you have an assistant, hold a shop vac to catch the grindings..should be a quick easy job.

[Robert Anglin]

Yep, can't tell you how many times we have just taken a fine point Sharpie, made a rough cut 1/16th. off that and then filed it to the mark.
It what we do with soft metals. Your call, Yours, R.E.A. III # 80888

[drdriddle]

+1 for the nested technique. Very easy and quick

[Ed_Wischmeyer]

In the time it takes to read all these posts, it's probably possible to enlarge the first hole...

:-)