I want to cut a 10" diameter hole in an 1/8" thick sheet of aluminum. I want it relatively accurate because it's going to mate to a cylinder. A bead of sealant (something like silicone) will seal the joint. No welding allowed, and the seal would only see pressure in an emergency. I'd like to find a tool like in the picture for the larger diameter. I've used it in a drill press to cut circles. Anybody know what it's called and where I might find them? Any other suggestions on how to cut the circle/circular section? Thanks, Kurt
It looks to me that the tool you pictured could be modified with an extended arm. That or just make a whole new one.
how about using a piece of string attached to an anchor point at the center to draw the circle then cut it with a hacksaw or pair of tin snips? i can see where it'd get out_of_round but take your time to minimise cleanup... is there a reason why it would have to be a perfect uniform cut?
yeah......then make sure you have a nice rigid pilot to rotate around, and spin it fairly slow in a drill press or mill. I've seen hole saws that big but they do a nasty job usually.
Do you have access to a plasma cutter? I used a piece of welding rod and hooked one end to the nozzle of the plasma cutter (the metal nozzel) and hooked the other to a screw I put in the center for a pivot. I coiled the rod around the nozzel and screw so it wouldn't slip out. I cut a PERFECT circle the very first time, and I'm an idiot most of the time. I guarantee you could do this. I was surprised how easy it was.
They are called 'circle cutters' or 'adjustable hole cutters', although I've not seen one that could go that big. If you decide to 'extend' that one, clamp your stock to a piece of plywood or pressboard & cut halfway thru from both sides using plenty of coolant and a low rpm. A carbide bit in a router would be much safer.... JMO CC
those "cutting tools" are also called "a fly cutter" they are pretty dangerous and actually designed for wood.. (although I'm sure someone will say otherwise) I am actually working on a circle shear project.. but at 1/8 inch thick the aluminum is thicker than what my project will be able to cut .. (what grade alum is it?) as far as other methods.. there was a thread on here a few weeks ago about milling aluminum with a wood router.. I would suggest you give this fixture a thought.. it would require that you drill a small hole in the center (where the blue arrow is) you might possibly need only drill halfway through?) and that you use a wood router with a new carbide bit.. IF YOU DO ATTEMPT THIS.. WEAR THE BEST SAFETY GLASSES, A SHEILD, GLOVES AND FOR GOD SAKE EAR PROTECTION. BECAUSE IT WILL BE LOUD..
find a sheet metal fabrication shop with a "ring and circle shear". they can cut circles from around 2 inches diameter up to 5 feet or more depending on the depth of the throut. they leave a small dimple in the center equal to a mark from a center punch . long beach city college has one and I'm sure you could probably find one at a city college or trade school near you and they would probably cut a circle for you if you ask.
How thick is the metal? A Malco Hole Cutter should do AL up to around .060. Try this link. http://malco.malcoproducts.com/products/shear/hc1.asp
The "fly cutter" is a real hazard at 3" -- 10" and it would be deadly. If you've got (or can borrow) a "nibbler" you could mount it to a rod as described and make a pretty good circle. Got a jig/saber saw? Get a metal cutting blade and hook the saw to a rod (make sure rod is aligned with front of blade) Or do your best with a set of tin snips and cut a circle about 1/2" smaller than the tank, make half-inch long cuts 1" apart around the circle and fold the tabs back, then cover with something. I'd consider some kind of split rubber tubing (maybe filled with silicone) or window gasket type material for the seal. Or find a steel ring the right size, put it under the Al and grab a hammer and cold chisel and start cutting! HTH
heres the plasma compass tech that i did in tech week http://www.jalopyjournal.com/forum/showthread.php?t=168789
..and that would probably be me , these are basic metal working tools found around just about any machine shop and yes they can be used on wood also... CC
I made a somewhat crude extension for the cutter and tried it on wood and one of the voices in my head said "not feeling safe" for several reasons. I don't have access to a plasma cutter or mill. I think I'll try a sabre saw with a pivot arm on a piece of steel (I don't wanna experiment on the $70 piece of 6061-T6 aluminum). I'll call around to see how much it'd cost for a shop to do it. And better yet would be to quit effing around and sign up for a local CNC machine shop class. Thanks, Kurt
those do look abit beter than the harbor freight one that i had try to brain me last summer but then i also was not using a drill press
MSC sells the cutter you are looking for but you will need a milling machine to cut the large diameter you need But if you have a band saw and a wood working router and a 1/2" shank flush trim router but you can make a part with in +or- 10 thou. its not all that hard once you understand that you can cut aluminum like you do hard wood with a good cutter (carbide) and a little less rpms on the cutter and a little lube wd40 wooks good. make a wooden template and router a blank of 1/8 alum with a flush trim bit make sure its a 1/2" shank or it will over heat and make a mess pm me if you need the details Bill
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