Instrument Hole Punch ATS-123C , Spruce P/N 12-02743 , ever use one ?

[Gillie]

I need to cut two 2.25 inst holes in the lower portion of my 1973 gcbc panel . I do not want to pull the panel to do it and that “shelf” that angles upward at the bottom of the panel that houses the mixture & F/R heat knobs , cig lighter , starter button , etc is in the way for using a conventional hole saw .
Spruce sells the above referenced hole punch ( sorry , but I am too ignorant to post a link ) and I was wondering if any of you kind folks have used this tool and would/wouldn’t recommend it ?

 

[Bartman]

Gillie, I have one, shoot me a PM with your address and I will send it to you.
Bart

 

[Big Ed]

You still might have issues with clearing the ledge. If so, it's pretty easy to lift the panel up higher without removing it. Remove nuts from the 4 shock mount bolts that hold the panel to the frame, plus any other random fasteners, and stick a pair of pry bars between the ledge and panel bottom. Be gentle and don't force it. When all the fasteners along the base are free, it will wiggle straight up at least a half inch with little or no force required. Pull your glare shield and look closely for any other fasteners to the frame, such as at the back of the radio rack, which might hold it down.

 

[Gillie]

Thanks Bart , Ed .
PM on the way Bartman

 

[Big Ed]

Related task: how to enlarge a 2" auto gauge hole to 2 1/4" aircraft gauge hole?

My A&P did one of my holes with a file. It looks terrible.

Panel is off the aircraft and I can remove all instruments, so am considering how to do a better job on the remaining 2 holes.

Seems like the punch tool would be tricky to center.

Am considering 3 approaches:

1. Big ass step bit.
2. Make a steel template, bolt to the panel, and use Dremel to remove the softer aluminum.
3. Rig up a template to center the arbor bit on a hole saw.

Am thinking #3 is probably the easiest, since I can put the panel on a drill press. If panel were mounted, #1 or #2 would be more likely to work.

Thoughts?

 

[Gillie]

#3 sounds like your best bet .
let me know what you did & how it worked out

 

[Bartman]

router bits cut the aluminum very nicely if you cut to within about 1/16" to 1/8" of the outline first with a very fine tooth blade in a handheld electric jigsaw. Make a template, clamp it into place and then use a pilot bit to go right around. Use WD-40 as a lubricant to keep the bit from chattering or picking up aluminum which will happen very quickly depending on the bit type.

 

[Bob Turner]

One of my hobbies is model trains. I do very precise cuts with a Dremel tool and cutoff discs.

Here is what I would do - mark it carefully with a scriber and layout dye. Cut close to, but not on, the line. The discs do not like aluminum, but they cut it anyway. Use face protection.

Then get a 2" rubber sanding drum and, being careful, dress the edges.

This is the same cut I make when I fit a cab to a boiler on a steam model - and almost the same dimension. I cannot have gaps.

But for airplanes I get a new sheet of .080 aluminum, carefully mark, and use a fly cutter. I get exactly the layout and spacing I want. Photo is in the instrument panel section - both J-3s and the Dec have panels cut like that. I did a Mooney in the 1970s that looked great! All panels were cut by me - same fly cutter.

For the models I use a fluorescent light with a magnifying glass in the middle. Airplane work I just use the face shield - usually don't need the magnification.

 

[Big Ed]

I went with a hole saw template with a bushing in the middle to guide the arbor bit.

Detailed instructions to fabricate are in the Tools and Jigs forum.