BIG HOLE

A fly cutter will make the cut. You need to have an excellent hold of the plate and you need a strong machine to turn it - a small drill press probably won't.

I responded before. I was very serious about using a carpenter's router with a small diameter carbide bit guided by a ball bearing run inside a template. You will get very accurate holes with quite an acceptable finish. If you do not have a router or woodworking tools, do you have a carpenter or cabinetmaker buddy?

^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Keep the whole world singing. . . . DanG

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if you are careful you can use an adjustable holecuuter that they sell for cutting large holes in wood, might have to cut from each side, I have used these to cut holes @10 in 1/4 inch plate , if I remember correctly I had to resharpen the cutter blade for it

msc and mcmastercarr both sell hole cutting setups designed for metal, real pricey though

or you can make your own holesaw using bandsaw blade around a piece of wood that you turn up in the lathe

Greetings Dan, That idea about using a router is a good one. Carbide router bits cut aluminum well. Brass too. One job I did required welding aluminum channel together. The wall thickness was 5/16". After welding the bead was ground flush so to get full penetration all the edges to be welded had to be beveled. A 1/4" bevel was what worked and that works out a .350 length of cut. The bevel was put on in one pass. It wasn't real pretty but we were going fast and the part was getting welded. But it worked so well I've used a router to put chamfers on large aluminum parts several times since. ERS

Take the plate to your local welding/machine shop who has a heavy duty plasma cutter. I'm pretty sure using a wood router is a recipe for a lot of broken bits for this application.

Stephen R.

Never tried it have ya! A wood working router with carbide bits and aluminum work great! Greg

Skillsaw with carbide tip blade will work great for a square hole.. You should have around 25 teeth or so. If you are looking for an expensive way buy a plasma cutter. Or find someone who has one, it will be a 5 min job for them.

yes he hasn't

carbide wood tools work like the devil on aluminum

I just finished a job cutting 300 aluminum fender skins for the local peterbilt plant , the shop they sent it to was milling them in a fixture with a slotting saw , I offered to do them for 15.00 dollars each { cutting 50mm off the width] they were glad to pay me

ran them through the old delta table saw , it was almost criminal

I could have sworn that trepanning is the process of putting additional holes in one head. Lets the demons out, I suppose.

Hmmm... so a carbide blade on my Makita table saw will cut aluminum? This is cool. I have a band saw which is great for square, hex and round stock, but is too small to cut 6" square sections out of large pieces of 1/4" aluminum plate. How many TPI should I be looking at?

Regards,

Peter

Had a similar job last week in a steel plate. First, lay out the hole. Use bluing so it can be easily seen. With a 5/8" roughing endmill( or whatever size you have), start working your way around the inside of the circle. Try to stay within about an 1/8" of the line. Accuracy at this point is not important. With the plug removed, mount a boring head in the mill. I have one that is 4" diameter and takes 3/4" tools. Place an appropriate boring bar in the head so that it sticks out as a radius. The head gives you the ability to slowly increase the size of the hole to clean up the rough endmill job. The mill table also gives you a chance to adjust the location.

On Fri, 30 Apr 2004 00:35:19 GMT, snipped-for-privacy@nospam.com brought forth from the murky depths:

Google gave me this:

it help? ;)

Then maybe this will:

be a newfangled hole saw.

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I use an eighty tooth crosscut blade with a little wd 40 squirted on the workpiece

you have to have a pretty good fence or cross cut sled

another thing is you just want the top of the blade to barely come through the piece of aluminum, too much blade height and the chips really fly, you will get a burr this way but much nicer than bites mof aluminum slinging at you

this is a situation for a face shield

I have thought about slowing down the speed on my saw with a different pulley combo , will try it if the fender cutting is recurring

80 tooth blade. Some people recomend buying a blade for cutting metal, but I have cut a fair amount of aluminum plate with just a 80 tooth carbide blade for wood. Also I cut dry, no lube, I did not want to muck up my saw with WD40. A power miter box cuts bar stock like a damn too. Watch out for round stock though, it will "roll" when cut, so you need to clamp it securely! Also watch out for the hot chips! Greg

Looks like a hole saw with a lot fewer, and much larger, teeth. I've seen them with carbide inserts even, IIRC. Think...hollow endmill.

Someone on here had to do a quickie and used a bit of 12L14 turned hollow on the end, milled with teeth notches and case hardened. There's a pic somewhere in the dropbox.

Remove all but one tooth and you basically get a fly cutter, maybe with some extra meat behind it (a flat disk to transfer from small spindle to large hole size, or a length of pipe to extend length without losing stiffness, as opposed to a thin spindle and single arm).

For your case I'd guess a hole cutter would work fine... just go slow.. got back gears?

Tim

-- "I have misplaced my pants." - Homer Simpson | Electronics,

- - - - - - - - - - - - - - - - - - - - - - --+ Metalcasting and Games:

Air-powered routers are the tool of choice for cutting big holes in aircraft. Spiral 1/8" carbide bits, with an up or down twist, depending on which way you want the chips to fly. No lube, usually, but it might not hurt for 3/8" stock. Beeswax or kerosene on the bit will keep the aluminum from sticking. The router has a base easily adapted to cutting circles.

The air routers don't turn any faster than electric ones, really, but they are much lighter for similar horsepower, run lots cooler, and help clear the chips.

If you don't plan to cut lots of holes, and have a powerful die grinder, you could fabricate a base using a thin board, three angle braces, a hose clamp, and a screw as a centering pin. BTDT. Don't muscle the cutter; let it cut at its own speed.

I've seen carbide spiral 1/8" bits in the box stores, in the Roto-Zip accessory section. Heck, even a Roto-zip could work, with a cobbled base. Haven't tried one of those, though. Probably a little short on power for plate stock.

Dale Scroggins

On Thu, 29 Apr 2004 20:31:08 -0700, Larry Jaques vaguely proposed a theory ......and in reply I say!: remove ns from my header address to reply via email

I....don't think I will take you up on that....

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I've cut alum bar up to 1.75 thick and plate over 1.00 on my table saw. Dress like you're going the distance on an Apollo mission.

michael

The sabre saw should have done the job in fairly short order. I use one frequently to rough out

6061 chunks for trim fixturing. Did you use a variable speed saw? When sabre sawing aluminum, there is a sweet spot as far as saw speed goes. Slow down the strokes per minute until it starts cutting efficiently. You want it to make chips, not dust. Use cutting fluid. I like Alumicut.

Bill