What to use to cut circles? [Archive]

Boomerang

08-06-01, 10:32 PM

The best way to cut very, very nice holes is with a hole saw. You can get them online, or at you local Home Despot or whatever. Another way is to use a device called a "Fly Cutter" that will cut variable size wholes. These are more expensive, but you only need one. With hole saws, you need one for every size hole you intend to cut. HTH.

Über~PhLuBB

08-06-01, 11:09 PM

Actually, the best way is with a die cutter. A hole saw isn't the ideal tool for cutting 2/32" sheet metal; it'll wear out quickly. I attached a drawing of a die cutter to help illustrate how it works. You can print it out and show it to someone at Home Depot, I'm sure they can help you find one of the appropriate size.

You simply drill a hole in the center of where you want a blowhole in your case, then put the bolt through the top portion or the cutter, then through the hole in the metal, then through the cutting piece, then thread the bolt on and tighten it with a wrench. You'll end up with a very nice, clean cut, no burrs, and if you take it slow and straight through, you wont even have to sand it to get rid of the sharp edges.

UnseenMenace

08-07-01, 04:37 AM

I use a Dremel its cheap, easy to use and gets a good finish and is usefull for so many things more than just cutting holes

Über~PhLuBB

08-07-01, 04:40 AM

Originally posted by UnseenMenace
I use a Dremel its cheap, easy to use and gets a good finish and is usefull for so many things more than just cutting holes

Oh my GOODNESS no... I ruined my last case with a Dremel. Worst tool EVER to make holes with. Dremels are OK for thinner metal, like... tinfoil (lol). 2/32" case sheet metal is too thick for 'em to be effective. Don't get me wrong--you CAN cut case sheet metal with a Dremel, you just wont get a clean hole, and that's what he wanted. Because nobody likes a sloppy hole. :D

RedDeathDrinker

08-07-01, 07:51 AM

Use a pair of compasses to mark a circle, drill holes round the inside of the circle, cut between the holes, use a dremel or like to smooth the edge.........Da Da.

I've done many holes like this, all perfect

Kingslayer

08-07-01, 11:50 AM

Hole saws. If you get the good expensive bi-metal saws designed for cutting metal, then you won't wear them out. Use plenty of oil, put 5 layers of duct tape around the area you are going to cut. (this will prevent scratches if you slip). And deburr the hole with a dremel or a file.

Another tip is to see if you can get a chunk of marine grade styrofoam. This is the thick yellow stuff that is used inside bouys. If you can get a 2'x2'x1' piece it would be perfect. What you do is lay the side of your case on this foam and then drill it out. This is also a good tip for cutting your case with a jig saw or cutting plexiglass with a jig saw. It will keep your case from buckling under the saw, and holds it steady and keeps it from jumping around when using a jig saw on your case. It will also prevent your plexi from jumping and shattering when cutting it with a jig saw.

Boomerang

08-07-01, 03:42 PM

Originally posted by PhLuBB
Actually, the best way is with a die cutter. A hole saw isn't the ideal tool for cutting 2/32" sheet metal; it'll wear out quickly. I attached a drawing of a die cutter to help illustrate how it works. You can print it out and show it to someone at Home Depot, I'm sure they can help you find one of the appropriate size.

You simply drill a hole in the center of where you want a blowhole in your case, then put the bolt through the top portion or the cutter, then through the hole in the metal, then through the cutting piece, then thread the bolt on and tighten it with a wrench. You'll end up with a very nice, clean cut, no burrs, and if you take it slow and straight through, you wont even have to sand it to get rid of the sharp edges.

I've always heard these things called knockout punches. You are right though. They are the best way to make a hole, but a 120 mm knockout punch is REALLY expensive (> $100). Again, you would need a different one for each hole size, just like like hole saws. If you can come by them, or know someone who has a good set of them, they are undoubtedly the best way to go.

Rob Cork

08-07-01, 04:51 PM

Originally posted by PhLuBB

Oh my GOODNESS no... I ruined my last case with a Dremel. Worst tool EVER to make holes with. Dremels are OK for thinner metal, like... tinfoil (lol). 2/32" case sheet metal is too thick for 'em to be effective. Don't get me wrong--you CAN cut case sheet metal with a Dremel, you just wont get a clean hole, and that's what he wanted. Because nobody likes a sloppy hole. :D
As long as you have a perfect circle drawn on the case side, all you have to do once you've cut the rough shape of the hole is grind away with one of the grinding bits to the pencil line. Then you'll have a perfectly circular hole. Granted, if you grind too much away the hole will look wonky, but I haven't done it yet and I've cut half a dozen holes with it to date. It's not impossible - and for the record, I love my dremel :D

klosters64a

08-07-01, 04:58 PM

PhLuBB's post illustrates what's known as a Greenly Punch. It may be spelled Greenley, Greenleigh or Greenly. Sorry, I don't remember.
"Greenley" isn't a generic term, as these punches are patented by Greenly.

They work very well. It's a bit time consuming to keep cranking the shaft, but cutting metal is usually APITA. The last time I checked, the larger Greenleigh's were a lot more than $100.

Assuming that the punch is available in the exact size you need, and you need to cut a lot of holes of that size, the Greenly's are a good investment, IMHO. However, a big drill press with a big table will cut faster, and hole saws aren't all that expensive. Dunno if the cutting oil messes up the paint of case covers. No matter, you'll have to use it with a hole saw.

Laser cut holes are the best--but I don't know how you contact the folks that have the lasers if you need 'em.

Electrical supply stores are where you find the Greenley Punch-- the stores that electricians go to.

FerrariF50

08-07-01, 08:02 PM

you need a Hole saw for the job

Crazy Jayhawk

08-07-01, 09:14 PM

I can tell you what doesn't work: Drilling holes in a circle and using diagonal cutting pliers to connect them. Slow and messy. Good thing the grille I put in covers all that on the outside. See here.

http://forums.overclockers.ws/vb/attachment.php?s=&postid=187024

sieb

08-08-01, 02:50 PM

Plasma Cutter... :) -da best

Actually, I just used a drill bit to do my small vent holes, then a larger bit to debur them. Then I used a 3" hole saw on a drill press. Make sure you lube it, and when cutting through steel, it makes alot of noise.

Berlin77

08-08-01, 10:30 PM

Check Radio Shack for a nibbler. It allows you to 'nibble' about 1/8x1/4 inch bites with each squeeze of the handle. I bought mine years ago. SHouldn't cost more than about $10 or so. Can be used to cut straight or curves. A little hard on the hands, but very useful!

Berlin77

08-08-01, 10:38 PM

Here's a link to RS
http://www.radioshack.com/product.asp?catalog%5Fname=CTLG&category%5Fname=CTLG%5F005%5F005%5F020%5F000&product%5Fid=64%2D823

The nibbler is part # 64-823 and costs $10

Owenator

08-09-01, 09:43 AM

I have used hole saws and tinsnips in the past. The tin snips can bend the edges but a little pounding with a hammer on an anvil or vise can flatten them out. IMHO any hole can be made 'perfect' with a little elbow grease and a some good metal files. I like the old blacksmith/craftsman feel I get when I know I have hand-made something from metal, but then again I am a bit wierd.

O

Mad_Heckler

08-09-01, 03:47 PM

I used to cut holes in sheet metal all day, and I found this to be the best tool to use in terms of being clean, easy to use, and cost effective. I think anyone that has used this will tell you the same.
I find regular holesaws to be great for wood, but suck for metal.

http://www.malcotools.com/products/metalduct/hc1.htm

Boomerang

08-09-01, 04:40 PM

That's what I was refering to as a "fly cutter". I just didn't have a picture of it. :)

Über~PhLuBB

08-09-01, 05:49 PM

Wow... that thing looks VERY useful. Do you know where I can buy one? I can use that for ALOT more than just my case...

Boomerang

08-09-01, 06:51 PM

Check out Home Despot or whatever you have along the same lines in your area. They should carry it. I would suggest taking a picture of it with you though, because the clerks will have no idea whatsoever what you are talking about.:) Good luck.

FerrariF50

08-09-01, 06:57 PM

Home Depot :)

Über~PhLuBB

08-09-01, 11:24 PM

Any ideas on how much they cost? (The 12 inch model) I'm not about to drop $500 on a new cutting tool when I already spent $110 on my 80MM die cutter.

joey_rjm5

08-10-01, 01:33 AM

I found the malco hole cutter here for 70 bucks:

http://www.aeductools.com/accessor.htm

It is about half way down the page under tools and miscellaneous accessories.

I am thinking about it.

joey_rjm5

08-10-01, 01:41 AM

Forget about that link, check this out. 50 bucks. I wonder if you need a drill press. Is the metal on our cases galvanized sheet metal. Anyways, here's the link. Enjoy!

http://www.bobstools.net/Store/Malco.html

Über~PhLuBB

08-10-01, 05:21 AM

Thanks alot man. I wont need my 80MM cutter anymore.

Boomerang

08-10-01, 02:37 PM

Some advice to anyone who buys one of these.
First, use cutting oil. If you don't, it'll be dead after just a couple of uses, especially on hard case steel. Second, use a drill press. If you try to use a hand drill, you won't go straight down, and as a result, the cutter will cut through on one side of the hole before the other side. It will then jam up and possibly break the cutting blade. Regardless of wether or not the blade breaks, the piece you are cutting will fly through the air, quite possibly taking your fingers with it. This brings me to my third point. Use a drill press, and if you can't find someone who has one and borrow theirs. Make sure to clamp your material down, and go VERY SLOWLY. If you go too fast, the same thing will happen as when you go in at anything other than 90 degrees. The cutting blade will catch, and your material will go flying.

Good luck to all who are buying these things, and try not to loose any fingers. :)

klosters64a

08-10-01, 02:49 PM

PC case steel isn't Galvanized, which is easy to spot. 'Fraid I can't describe it, but once you've seen it you'll always remember it. Oh, don't ever use galvanized steel pipe for plumbing--at least for supplying water. The layer of ?zinc is very thin, and it'll be rust city until the pipe is replaced.

Rob Cork

08-10-01, 06:15 PM

Galvanised steel is easy to spot, the surface of the Danger Den copper cooling cube is galvanised. The Zinc on the surface is single phase, polycrystalline if I remember my Materials Science correctly. Within a crystal (about 5mm across normally) you can see a lamellar pattern - looks kinda like a fern leaf :)

Ordinary steel just looks boring, a flat metal finish.

Bender

08-11-01, 07:37 PM

I have had great luck with my Fordom tool. Its a super high end 1/8 hourse power jewlers rotary tool with a flexi shaft. My dad found it brand new at a garage sale for $10 but the retail is around $300. I draw a hole preferably with a compase and use pummice cutting disks. The finish is usually very smooth and easy to work with. I wish I had a hole saw but I don't want to spend any money. If you cut slowly and carefully you will be supprised with the results.

CrystalMethod

08-11-01, 07:53 PM

Saw a funky looking diamond wheel for the Dremmel, there was also a simmilar shaped wheel for irregular shaped holes. Any one tried those yet? Also has any one tried the "Roto-Zip", bits for the dremmel? Kinda been wondering how thoouse would do.

Über~PhLuBB

08-11-01, 10:37 PM

Originally posted by CrystalMethod
Saw a funky looking diamond wheel for the Dremmel, there was also a simmilar shaped wheel for irregular shaped holes. Any one tried those yet? Also has any one tried the "Roto-Zip", bits for the dremmel? Kinda been wondering how thoouse would do.

My friend has a Dremel we tried on our cases. We used a diamond tip bit, it's a long 3/4" long cone shape cut off at the end. All it did was superheat the metal so much that it melted the paint up to a half inch away from the cutting area--unacceptable. We also tried one of those malicious looking bits shaped like a cone, with little blades running longwise down the bit. That one worked for smoothing out burrs, but it was HORRIBLE for the actual cutting. It left the edges disfigured beyond repair. I ended up having to put molding along the cut edges to hide the uneven edges.

Like we've been saying, so called "Greenleigh" cutters, hole saws, and that Matco hole cutter are the best tools.

Mad_Heckler

08-12-01, 01:36 PM

When you use the Malco cutter, you dont have to use a drill press, in fact I dont know how well it will work if you do. Cutting oil may help, but this is a professional tool and you will not break the bit, and it does not dull that fast. Thanks to the person for posting to link for $50.00, the price does vary a bit since alot of the places that carry this supply contactors and they are willing to spend more on tools.

CrystalMethod

08-12-01, 06:02 PM

Originally posted by PhLuBB

My friend has a Dremel we tried on our cases. We used a diamond tip bit, it's a long 3/4" long cone shape cut off at the end. All it did was superheat the metal so much that it melted the paint up to a half inch away from the cutting area--unacceptable. We also tried one of those malicious looking bits shaped like a cone, with little blades running longwise down the bit. That one worked for smoothing out burrs, but it was HORRIBLE for the actual cutting. It left the edges disfigured beyond repair. I ended up having to put molding along the cut edges to hide the uneven edges.

Like we've been saying, so called "Greenleigh" cutters, hole saws, and that Matco hole cutter are the best tools.

I didn't mean the grinding bit. It's a cutoff wheel, but made to cut irregular shaped holes.

Boomerang

08-12-01, 10:29 PM

Originally posted by PhLuBB

My friend has a Dremel we tried on our cases. We used a diamond tip bit, it's a long 3/4" long cone shape cut off at the end. All it did was superheat the metal so much that it melted the paint up to a half inch away from the cutting area--unacceptable. We also tried one of those malicious looking bits shaped like a cone, with little blades running longwise down the bit. That one worked for smoothing out burrs, but it was HORRIBLE for the actual cutting. It left the edges disfigured beyond repair. I ended up having to put molding along the cut edges to hide the uneven edges.

Like we've been saying, so called "Greenleigh" cutters, hole saws, and that Matco hole cutter are the best tools.

Dremel makes a similar bit to the cone shaped one with the edges, but it's longer and skinnier. It isn't cone shaped, instead, it's kind of shaped like a drill bit. I used it to cut a hole in a case, and it worked great. I would recommend it for any complex shapes. HTH.

CrystalMethod

08-13-01, 12:07 AM

Found a pic of it...
Here. (http://images.amazon.com/images/P/B0000302ZZ.01.LZZZZZZZ.gif)
There's a diamond cutter shaped like this as well, but I couldn't find a picture of it.

Über~PhLuBB

08-13-01, 12:18 AM

That is one evil looking tool. (I know it's only an inch in diameter).

I still think the greenleigh or Matco hole cutters work best.

M@€$†®Ö™

08-13-01, 04:43 AM

Now this is a good thread !

Maestro

M@€$†®Ö™

08-13-01, 04:57 AM

That Malco Hole Cutter sounds like the ticket ride thanks for the links and info.

Maestro

Boomerang

08-14-01, 12:18 AM

Here (http://www.dremel.com/html/home_fr.html) is the side cuttng bit that I and others have mentioned. It is plunged directly (point first) into the metal, and then you just draw your hole. It has worked well for me cutting a biohazard symbol in the side of a case (for pix, look back to old posts). The only problem I had with it was that it could not do really fine corners. All corners ended up having a 1/8 inch curve to them, which somewhat limits it's usability. In finding this link though, I found that there are several smaller bits that would probably work well for cutting cases with even finer detail. Hope someone finds all this useful.

joey_rjm5

08-14-01, 05:14 PM

I think I will go with the malco cutting tool. For 50 bucks and the 2-12 inch range, I don't think you could go wrong. I'll try to find out the ideal tool to use it with, but if somebody else would be willing to, that would be cool. I just started my senior year and have alot of hard @$$ A.P Physics to do.

Mad_Heckler

08-14-01, 10:04 PM

I am glad you guys will find good use for the Malco, it has served me well.

Bluesmoke

08-18-01, 01:27 AM

I used a cdrom disk as my template for my 120mm blowhole on the top of my case and cut it out with a sabre saw with a metal cutting blade. Came out pretty decent... not ugly... It worked for me... going to add some narrow black gasket material around the edge to make it perfectly round.. (its almost there now but drifted off the line a bit here and there :) )

parkan

08-18-01, 12:41 PM

I use a power nibbler I got from micromark, it costed $130 but it's a great tool.

KeyboardCowboy

08-19-01, 02:55 PM

recently i was walking through home depot, trying to find a certian thing, and i was distracted by a set of hole saw bits, from like 40mm-140mm for 100 bucks, i find holesaw bits work fine, just have to suport the piece that you are drilling with a piece of wood underneath

altheakim

08-11-08, 04:42 AM

To make a perfect circle, you'll need to use either a diamond-tipped of tungsten carbide grit hole saw, and run water over it while cutting, to keep from over-heating it. The hole saw will cost around $80-$100.
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althea

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