Cutting Inspection Holes

lawsondj · Post by **lawsondj** » Sat Feb 18, 2012 10:27 am

Need Some Advice.

Has anyone found a good method or tool to cut large diameter holes in sheet metal. Perhaps 5-6" diameter holes, like for inspection holes.

Thanks, Jack
SR193

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Al Paxhia · Post by **Al Paxhia** » Sat Feb 18, 2012 10:27 am

Not a great solution but it works. I use a fly cutter, I first drill a 1/4"
hole then replace the bit in the fly cutter with a 1/4 shaft. This keeps the
pilot hole from being hogged out from the bit. If the metal is light I use
a plywood backing board, go slow and keep the cutter sharp.
Al
----- Original Message -----
From: <lawsondj@comcast.net>
To: "Murphy Rebel Builder's Gr" <rebel-builders@dcsol.com>
Sent: Tuesday, April 19, 2005 9:17 PM
Subject: Cutting Inspection Holes

Need Some Advice.

Has anyone found a good method or tool to cut large diameter holes in
sheet metal. Perhaps 5-6" diameter holes, like for inspection holes.

Thanks, Jack
SR193

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Mark Myres · Post by **Mark Myres** » Sat Feb 18, 2012 10:27 am

Hello Jack,
Building the Rv series I used a fly cutter and had very good luck. I
tryed to always have a smooth piece of hardwood under the aluminum and cut
very slow with the aluminum clamped at one edge to keep the initial
breakthrough from spining the aluminum. You will know when the cut is
breaking through because an edge will show through to the wood. This is your
key to go slower yet. The pilot bit is always in the wood acting like an
axle to a wheel. Try it out on a test piece. good luck . Billy
----- Original Message -----
From: <lawsondj@comcast.net>
To: "Murphy Rebel Builder's Gr" <rebel-builders@dcsol.com>
Sent: Tuesday, April 19, 2005 9:17 PM
Subject: Cutting Inspection Holes

Need Some Advice.

Has anyone found a good method or tool to cut large diameter holes in
sheet metal. Perhaps 5-6" diameter holes, like for inspection holes.

Thanks, Jack
SR193

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Drew Dalgleish · Post by **Drew Dalgleish** » Sat Feb 18, 2012 10:27 am

At 04:17 AM 4/20/2005 +0000, you wrote:

Need Some Advice.

Has anyone found a good method or tool to cut large diameter holes in

sheet metal. Perhaps 5-6" diameter holes, like for inspection holes.

Thanks, Jack
SR193

I used a fly cutter with good results but they are scary to use. I've seen
advertised circle cutter attachments that go with a dremel tool which would
also probably work well. The ideal tool is a greenlee punch but they're
very expensive in the larger sizes and you need a different one for each
size hole. I have a bunch of small ones that were passed down to me and
they're my first choice.
Drew

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Ken · Post by **Ken** » Sat Feb 18, 2012 10:27 am

This won't sound elegant but if it is larger than a 3.5" hole saw, I use
any combination of hand shear, nibbler, or tinsnips that is handy. Then
I do the final 1/16 to 1/8 or so with a half inch cutter in a die
grinder and a quick touch up with a sanding drum in the drill. Works
well for me but as previously discussed one needs an occasional bit of
lubricant of some kind on the cutter to keep it from loadin (plugging)
up. The $40. air powered shear will get to within 1/16 of the finished
edge for any straight lines in oval holes or straight cuts (instrument
panel radio holes). For think 0.020 stock, I've seen small tinsnips from
"Industrial Tool" work very nicely followed by just a quick touch up
with a drum sander. The $25. die grinder cleans up irregular holes so
fast (much faster than a dremel) that sometimes I just drill out a line
of holes with a #30 or so bit.

I've used a router to do long straight edges but it would also do a nice
job on large holes.

Ken
119R

lawsondj@comcast.net wrote:

Need Some Advice.

Has anyone found a good method or tool to cut large diameter holes in

sheet metal. Perhaps 5-6" diameter holes, like for inspection holes.

Thanks, Jack
SR193

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Mark Myres · Post by **Mark Myres** » Sat Feb 18, 2012 10:27 am

----- Original Message -----
From: "Mark Myres" <myres@whidbey.com>
To: <rebel-builders@dcsol.com>
Sent: Wednesday, April 27, 2005 10:19 PM
Subject: Re: Cutting Inspection Holes

Hello Jack,
Building the Rv series I used a fly cutter and had very good luck. I
tryed to always have a smooth piece of hardwood under the aluminum and cut
very slow with the aluminum clamped at one edge to keep the initial
breakthrough from spining the aluminum. You will know when the cut is
breaking through because an edge will show through to the wood. This is
your
key to go slower yet. The pilot bit is always in the wood acting like an
axle to a wheel. Try it out on a test piece. good luck . Billy
----- Original Message -----
From: <lawsondj@comcast.net>
To: "Murphy Rebel Builder's Gr" <rebel-builders@dcsol.com>
Sent: Tuesday, April 19, 2005 9:17 PM
Subject: Cutting Inspection Holes

Need Some Advice.

Has anyone found a good method or tool to cut large diameter holes in
sheet metal. Perhaps 5-6" diameter holes, like for inspection holes.

Thanks, Jack
SR193

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Joel Jacobs · Post by **Joel Jacobs** » Sat Feb 18, 2012 10:27 am

I'm suprised no one mentioned this:
http://www.aircraft-tool.com/shop/detai ... UCT_ID=HC1

Mine sure works great. Just use a bit of cutting oil with it...
Joel

----- Original Message -----
From: <lawsondj@comcast.net>
To: "Murphy Rebel Builder's Gr" <rebel-builders@dcsol.com>
Sent: Wednesday, April 20, 2005 12:17 AM
Subject: Cutting Inspection Holes

Need Some Advice.

Has anyone found a good method or tool to cut large diameter holes in

sheet metal. Perhaps 5-6" diameter holes, like for inspection holes.

Thanks, Jack
SR193

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Warren & Marg Montgomery · Post by **Warren & Marg Montgomery** » Sat Feb 18, 2012 10:27 am

I recommend the fly cutter as already discribed.
As Ken says a wood router with a carbide bit does a nice clean up of
even heavy stock such as the .060 sills.
Just hack out to within a 1/16" or so then clamp on a straight edge and
clean up with the router. Saves many hours of filing.

Ken wrote:

I've used a router to do long straight edges but it would also do a nice

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lawsondj · Post by **lawsondj** » Sat Feb 18, 2012 10:27 am

Thanks to everyone who replied!!!

Most popular seems to be the fly cutter,but is hard to control driven by hand tools.The ATS hole cutter seems to be the appropriate tool for the job.

Jack
SR193

-------------- Original message --------------

I'm suprised no one mentioned this:
http://www.aircraft-tool.com/shop/detai ... UCT_ID=HC1

Mine sure works great. Just use a bit of cutting oil with it...
Joel

----- Original Message -----
From:
To: "Murphy Rebel Builder's Gr"
Sent: Wednesday, April 20, 2005 12:17 AM
Subject: Cutting Inspection Holes

Need Some Advice.

Has anyone found a good method or tool to cut large diameter holes in
sheet metal. Perhaps 5-6" diameter holes, like for inspection holes.
Thanks, Jack
SR193

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Wayne G. O'Shea · Post by **Wayne G. O'Shea** » Sat Feb 18, 2012 10:27 am

A fly cutter can be VERY dangerous even in a drill press. Make sure your
sleeves are rolled up and things are clamped down. Yes I use a fly cutter
from time to time, but as rarely as I possibly can!

I use the exact ATS circle cutter that Joel has pointed out, when cutting
access holes in thin sheet (.016 to .040). It works like a dream. When you
get about half way around have someone tape the opened side together so it
doesn't shift just as you finish the cut. I also suggest to stop about 3/8"
short of completing the hole and finish with snips. Using this tool makes a
perfect hole in any size you want in less than 2 minutes...without the
danger of the fly cutter flying apart or snagging your shop coat/sweater.

Cheers,
Wayne

----- Original Message -----
From: <lawsondj@comcast.net>
To: <rebel-builders@dcsol.com>
Sent: Wednesday, April 20, 2005 8:13 PM
Subject: Re: Cutting Inspection Holes

Thanks to everyone who replied!!!

Most popular seems to be the fly cutter,but is hard to control driven by

hand tools.The ATS hole cutter seems to be the appropriate tool for the job.

Jack
SR193

-------------- Original message --------------

I'm suprised no one mentioned this:
http://www.aircraft-tool.com/shop/detai ... UCT_ID=HC1

Mine sure works great. Just use a bit of cutting oil with it...
Joel

----- Original Message -----
From:
To: "Murphy Rebel Builder's Gr"
Sent: Wednesday, April 20, 2005 12:17 AM
Subject: Cutting Inspection Holes

Need Some Advice.

Has anyone found a good method or tool to cut large diameter holes in
sheet metal. Perhaps 5-6" diameter holes, like for inspection holes.
Thanks, Jack
SR193

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Ken · Post by **Ken** » Sat Feb 18, 2012 10:27 am

Hi Joel
Is that just a flycutter or is there a planetary gear or something in it
to slow it down?
Ken

Joel Jacobs wrote:

I'm suprised no one mentioned this:
http://www.aircraft-tool.com/shop/detai ... UCT_ID=HC1

Mine sure works great. Just use a bit of cutting oil with it...
Joel

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Wayne G. O'Shea · Post by **Wayne G. O'Shea** » Sat Feb 18, 2012 10:27 am

No Ken, all it is is a bearing'd milling bit in a handle. You first drill a
center hole where you want the circle cut out. Then you attach your drill to
the bit shaft, set the pivot hole point to the hole diameter you want on the
adjustable scale......grab the handle and hold pressure against the pivot
point/hole and have at her. Let the bit do the cutting and just maintain
pressure against the pivot hole and in the direction of cut.

Wayne

----- Original Message -----
From: "Ken" <klehman@albedo.net>
To: <rebel-builders@dcsol.com>
Sent: Wednesday, April 20, 2005 11:19 AM
Subject: Re: Cutting Inspection Holes

Hi Joel
Is that just a flycutter or is there a planetary gear or something in it
to slow it down?
Ken

Joel Jacobs wrote:

I'm suprised no one mentioned this:
http://www.aircraft-tool.com/shop/detai ... UCT_ID=HC1

Mine sure works great. Just use a bit of cutting oil with it...
Joel

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carol and murray cherkas · Post by **carol and murray cherkas** » Sat Feb 18, 2012 10:27 am

Hello

Mark the hole with a dry wall circular cutter. Drill a 1/2" hole to get
started to insert a nibler. The nibler will cut a pretty good hole. Practice
first.

Good Luck
Murray
----- Original Message -----
From: "Drew Dalgleish" <drewjan@cabletv.on.ca>
To: <rebel-builders@dcsol.com>
Sent: Wednesday, April 20, 2005 6:06 AM
Subject: Re: Cutting Inspection Holes

At 04:17 AM 4/20/2005 +0000, you wrote:
Need Some Advice.

Has anyone found a good method or tool to cut large diameter holes in
sheet metal. Perhaps 5-6" diameter holes, like for inspection holes.
Thanks, Jack
SR193
I used a fly cutter with good results but they are scary to use. I've seen
advertised circle cutter attachments that go with a dremel tool which
would
also probably work well. The ideal tool is a greenlee punch but they're
very expensive in the larger sizes and you need a different one for each
size hole. I have a bunch of small ones that were passed down to me and
they're my first choice.
Drew

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N.Smith · Post by **N.Smith** » Sat Feb 18, 2012 10:27 am

Hi All

A bit of a smaller hole maybe......but I have this and it works a treat for
the price.

http://www.chiefaircraft.com/cgi-bin/ai ... em=/Aircra
ft/Tools/InstrumentPanel.html

You'll probably need to join the two lines of address together to make the
link work !

Nigel
745E

-----Original Message-----
From: mike.davis@dcsol.com [mailto:mike.davis@dcsol.com]On Behalf Of
Joel Jacobs
Sent: 20 April 2005 14:19
To: rebel-builders@dcsol.com
Subject: Re: Cutting Inspection Holes

I'm suprised no one mentioned this:
http://www.aircraft-tool.com/shop/detai ... UCT_ID=HC1

Mine sure works great. Just use a bit of cutting oil with it...
Joel

----- Original Message -----
From: <lawsondj@comcast.net>
To: "Murphy Rebel Builder's Gr" <rebel-builders@dcsol.com>
Sent: Wednesday, April 20, 2005 12:17 AM
Subject: Cutting Inspection Holes

Need Some Advice.

Has anyone found a good method or tool to cut large diameter holes in

sheet metal. Perhaps 5-6" diameter holes, like for inspection holes.

Thanks, Jack
SR193

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Joel Jacobs · Post by **Joel Jacobs** » Sat Feb 18, 2012 10:27 am

----- Original Message -----
From: "Wayne G. O'Shea" <oifa@irishfield.on.ca>
To: <rebel-builders@dcsol.com>
Sent: Wednesday, April 20, 2005 9:37 PM
Subject: Re: Cutting Inspection Holes

I use the exact ATS circle cutter that Joel has pointed out, when cutting
access holes in thin sheet (.016 to .040). It works like a dream. When you
get about half way around have someone tape the opened side together so it
doesn't shift just as you finish the cut.

I usually just stick the point of a pencil in the slot after I get about 3/4
around and that keeps it from shifting as I finish the cut. I put cutting
oil on the surface first - tape wouldn't stick!

Joel

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