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Cutting one hole for an instrument

T

tectweaker

Well Known Member
Need to add a small instrument to my panel. Don't have a hole for it in the panel.

I see several ways to do it (including tools) if I took the complete panel out.

Is there a safe way to do it without taking out the whole panel out and removing the existing instruments?

It is a small egt gauge so getting behind the panel and installation is not problem.
 
If you need a round hole (2-1/4"?) the Greenlee punches work great and would be suitable for in situ work.
 
A hole cutting attachment for a drill from Home Depot (intended for wood) will cut a couple of holes before getting too dull. Use Boelube or equivalent.
 
BobTurner said:
A hole cutting attachment for a drill from Home Depot (intended for wood) will cut a couple of holes before getting too dull. Use Boelube or equivalent.
Click to expand...

A little tip when using a tool like this ----most hole saws have a replaceable drill bit in the center. First off drill the pilot hole just like normal, then before you start to cut the outer hole, extend the center drill out enough that the flutes are no longer in the pilot-------just the straight shank of the drill bit. Or, reverse the drill works sometimes. The idea is to not have the pilot drill be able to wallow out the pilot hole. Or, use a separate bit to drill the center hole, and a straight rod as a pilot in the hole saw.

Hope this makes sense----------hole saws tend to grab when using them, and it can cause the pilot drill to distort the pilot hole.
 
If you can't find a hole saw that's the right diameter & don't want to invest in a Greenlee punch for one hole, it *can* be done with a 'flycutter' (ebay calls them 'circle cutters'.
http://www.ebay.com/sch/i.html?_odkw=woodworking+flycutting+bit&_from=R40%7CR40&_osacat=0&_from=R40&_trksid=p2045573.m570.l1313.TR0.TRC0.H0.Xwoodworking+circle+cutter+bit&_nkw=woodworking+circle+cutter+bit&_sacat=0

It's easier if the flycutter has 2 cutting bits, and the cutting bits look like a chisel instead of a knife edge (The Harbor Freight version cutters look like knives). Better example:
http://www.ebay.com/itm/Adjustable-Plane-Type-30mm-to-120mm-Round-Circle-Hole-Cutter-Hex-Key-Wrench-/390963487293?pt=LH_DefaultDomain_0&hash=item5b073d623d

Start with scrap wood to be sure that you've got both bits on the same radius, and to get used to the tool trying to destroy the work (and you). Use a good quality drill motor that will supply full torque from 0 rpm to under 100 rpm. Drill the pilot hole, then use a non-bit pilot in the flycutter like Mike said. Sit in the plane, brace yourself, and start cutting *very* slowly. It will take a while, so be patient. It's not a bad idea to set up the cut about 1/16" undersize (it's difficult to hold the drill perfectly perpendicular, and the hole will get bigger if you don't). After cutting through, dress it to final size with a small Scotchbrite drum.

As unlikely as it sounds, I've done it and it will work if you take your time and are careful.

Charlie
 
One hole? I'd opt for the Greenlee punch - less mess, less chance of damage to you, the airplane, and surrounding equipment if the fly-cutter decides to start going wonky. Someone near San Jose must have one - if not, plan a cross-country up over the Sierra and come use ours.

Paul
 
I had to make some small holes (1 1/4) in my panel for UMA gages. I tried several things but what worked best for me was a hole cutter I got from Travers tool, you can find them on the web. They have some hole cutters that are much better and smoother than the bimetal Home Depot type saws. They cut aluminum like a razor cuts paper.
 
Buy, rent, borrow, steal, or whatever you have to do to get your hands on a Greenlee punch!

Those other methods will make the biggest mess you've ever seen in the cockpit.

Don't ask me how I know, either! :rolleyes:
 
What Ironflight and PCHunt said.
One little tiny chip from one of those Other brutal grinding tools can end up in one of your instruments or switches and become a " gremlin" you'll never find.

Someone will have a Greenlee punch nearby or else take up Paul on his offer.
 
I would absolutely NOT use a hole saw for this if you're not going to take all the other equipment. You don't want all that small metal shards and, more important, dust getting everywhere.

Borrow the Greenlee punch, one hole, insert, turn with a wrench...boom... one hole.
 
I think that I am convinced on the greenlee.

Anybody has it locally?

I am at LVK airport. Won't absolutely not mind flying around for non-essential reasons:)

Since I did not build the plane - I am learning all the details now :)
 
I've done this the hard, messy way before.

I made a bag slightly larger than the hole and taped it on the back of the panel to catch any debris. Then I laid drop cloths and towels across the canopy and cockpit to catch the chips and shavings.

I cut the hole, removed the bag and the drop cloths, and I was done.

Sometimes the brute force method is easier than trying to scrounge up the perfect tool.
 
Many EAA Chapter have a Greenlee that's shared by chapter members . Maybe you could try contacting those that are within a short flight distance from your home field?
 
LVK EAA chapter 663 has 2 1/4 and 3 1/8" punches. Of course you should join if you want to use the chapter's tools.
 
Even with the punch it can be tricky to do in the airplane. It requires a large pilot hole. If you can't find help at LVK, you are welcome to fly up to O61 and we will punch the new hole.
 
punch for sale

I have a punch for instruments, 2-1/8 one side, 3-1/4 other side. Email me if interested.
 
Thank you all for the offers.

I really don't think that I know what I am doing "yet" so it would be good to get some help.

I will join EAA shortly Bob and perhaps also get some guidance as well :)

Mike - I was just flying in that area. Will PM you on your schedule - perhaps I can drop by for few minutes to get this done.
 
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