VK Logger Ham Radio Forum Archive

Hi,
I have a project that has been taking me a long time to get going, at the heart of it there is a need to cut a largish round hole in a metal front panel of a rack case to then mount a muffin fan on the inside of the panel

The hole will be seen once completed and needs to look good. I have not had much luck with these in the past and never found a way to do it neatly. A hole saw and a file has been used in the past but I am over the frustration of scratches on the panel afterwards.

I had considered buying a milling machine to do these but do not do them too often so its a big expense for a small number of a jobs.

Okay, how do others cut round or for that matter square holes in aluminium panels and not make it look like the mad hatter tea party has been let loose?

Ideas, web sites, companies that do small jobs?

regards,

Is your panel soft alloy or steel.

For alloy panels I have successfully used circular (saw teeth) hole cutters with the careful use of some light lubricant. I mount the cutter in the drill press at low revs and cut through the panel into a piece of offcut ply. I bought a set of these cutters off evil-bay for very little, intended I think for cutting round holes in wood or plaster board.

For steel, even if thin, this wont work and will just destroy the teeth on the cutter. I had to mount two muffin fans in the side of a 19" 3U rack panel containing my Larken 6m amplifier panel. The side wall were thin steel but I had to use the old fashioned ring of drill holes, knocked out and then filed true by hand with a half-round file.

Slow and laborious and risks some scratches if care not taken to protect the surface.

VK4UH KJ

A hole punch or a chassis punch makes a very clean cut but iv only seen up
to 25mm or so.

Knockout punch - Wikipedia, the free encyclopedia
https://en.wikipedia.org/wiki/Knockout_punch
A knockout punch, also known as a chassis punch, panel punch, Greenlee punch, or a Q-max, is a hand tool used to punch a hole through sheet metal.

73
Mark

I had a similar job to do. After stuffing up a couple of attempts I took it to a local sheet metal company and they did it in a couple of minutes for only a few dollars and even beveled the edges.

73

Wayne VK4WDM

I find a nibbler works very well, and with a bit of effort, is quite accurate too! Just a little finish up with a half round file and job done! Nibbler is great for round holes, square holes, switch cutouts and many more things.

Peter I have successfully used hole saws with a drill press. If you can remove the panel and clamp it carefully face down to a clean block of wood.
When drilling apply pressure very slowly and apply cutting oil and it should work ok. I have used this method for sheet aluminium many times.
Make sure its a good quality hole saw.

good luck

Hi Peter,

I use a set of hydraulic hole punches...we used to have a set at work years ago, and I recently saw a set on ePay...hand operated pump, and multiple punches from about 10mm through to about 70mm. They easily punch Ally and then steel.

The set was about $200 from memory ( Chinese of course, and not a patch on the one we had at work, but will outlast me regardless ).

Obviously, $200 is a bit much to punch one hole, but if you get a set, it is infinitely easier than holes saws etc, and leaves a great finish.

I'll happily punch a hole for you if I have a punch big enough...but postage each way may cruel that idea !

73
Glenn
VK4BG

VK5PJ wrote:Hi,
I have a project that has been taking me a long time to get going, at the heart of it there is a need to cut a largish round hole in a metal front panel of a rack case to then mount a muffin fan on the inside of the panel

The hole will be seen once completed and needs to look good. I have not had much luck with these in the past and never found a way to do it neatly. A hole saw and a file has been used in the past but I am over the frustration of scratches on the panel afterwards.

I had considered buying a milling machine to do these but do not do them too often so its a big expense for a small number of a jobs.

Okay, how do others cut round or for that matter square holes in aluminium panels and not make it look like the mad hatter tea party has been let loose?

Ideas, web sites, companies that do small jobs?

regards,

Fly cutter
sharper better
Drill pilot hole and set outrigger arm accurately with new piece of tool steel and use drill press bench not by hand.
or get it laser cut at auto engineering shop if its portable and that important.
Some engineering shops have dies but 5 and 1/4 is pretty big.
2c

Hi Glenn

VK4BG wrote:Hi Peter,
I use a set of hydraulic hole punches...we used to have a set at work years ago, and I recently saw a set on ePay...hand operated pump, and multiple punches from about 10mm through to about 70mm
73 Glenn VK4BG

Great idea Glenn, have gone through the listings and found one that has a collections of Die's up to 104 mm (close enough to the 110mm I wanted to cut) at $260 it will be an investment and can take it anywhere I go, especially if I need to cut a hole in a shed wall etc.

Regards,

We know who to call when we need 5.25 muffin holes then

VK3ZAZ wrote:We know who to call when we need 5.25 muffin holes then

will set up a table at SERG and do them while you wait.

Maybe Peter can sell muffins at SERG to recoup some of the cost

73

Wayne VK4WDM

About all I can add is if using a hole saw that has a 1/4" pilot drill. Replace the drill with a decent 1/4" rod, drilling the hole separately first. I have found the the drill tends to walk about and enlarges the pilot hole.
Allan
VK2EFM

Replace the drill with a decent 1/4" rod, drilling the hole separately first. I have found the the drill tends to walk about and enlarges the pilot hole.

My hole saw set has a rod in it. I have always wondered what it was for, now I know.

73

Wayne VK4WDM

Peter,
Just remember to lube the cutting faces of the die-set between each use.

This will ensure the tool last longer & stays sharp, also makes it easier to remove the cut-out disc and die-set from the job after the hole is cut.

Peter (VK5KX)

Maybe something like:


http://www.altronics.com.au/p/h5185a-3u ... ack-panel/
and

http://www.altronics.com.au/p/h5186-bla ... it-h-5185/

VK5KX wrote:Peter,
Just remember to lube the cutting faces of the die-set between each use.
Peter (VK5KX)

Thanks Peter, will take heed of that and get the light machine oil tin out in readyness for my first cut.

Laser cut at a local machine shop, accurate and no damage to panel.
JUG