Making a large-ish hole in aluminum plate

[spike7638]

I made this:

out of some scrap dock a day or two ago (that explains the two extra holes -- one near the bottom, one at the edge of the main hole). The large hole is 1.125 (+/- .05 !), and I made it by chucking up a cheap hole-saw into a chuck in the milling machine and gradually working my way through the 1/4" aluminum plate. It was blind luck that I had a hole-saw of the size I needed, and after I sharpened up the teeth a bit, it all went OK. But before I found that hole-saw, I was saying to myself, "How the heck am I gonna cut this hole? I don't have any 1 1/8 drills..."

In wood, I'd probably use a trammel cutter, which tends to cut a rough hole, and then smoothed things up a bit with rasps/sandpaper/whatever. If the lathes at the shop had 4-jaw chucks, I could have squared off the piece (the bottom inch isn't needed, but it didn't need to be cut off either) and cut the hole on a lathe. But supposing that the thing above -- rectangular, with the hole off-center --- really was what I needed, is there something like a trammel-cutter (but perhaps a little more sophisticated and less subject to vibration, etc.) that I could have used in the milling machine?

 

[tjb]

Rotary table

 

[Asm109]

The tool you seek is a boring head. Criterion makes a deluxe model.

 

[MrCrankyface]

I'd use the biggest drill/holesaw I had on hand to save time and then get it to perfect size with a boring head.

 

[spike7638]

The tool you seek is a boring head. Criterion makes a deluxe model.

Thanks.
Can you amplify a little bit? (I'm really an almost complete novice). This video

shows how I could enlarge a hole...so do I start with a 1/2-inch drill, say, and then successively enlarge with the boring head
until I reach 1.25"?

 

[Turner]

I'd use the biggest drill/holesaw I had on hand to save time and then get it to perfect size with a boring head.

What he said, from another noob.


Sent from my iPhone using Tapatalk

 

[MrWhoopee]

It's called a trepanning tool. This one is shop made (and won't make a hole that small), but they are available.


Your money is probably better spent on a set of these,

10PC Carbide Tip TCT Hole Saw Cutter Drill Bit Set For Steel Metal Alloy 16-53mm 977606341502 | eBay

If the hole cutter you are using often has uneven welding that causes the cutter to break teeth, high-temperature friction that burns and deforms the cutter, or a core that breaks easily, then you need to replace it with a better hole cutter.

www.ebay.com

and a boring head.

 

[FOMOGO]

If you have a set of hole saws ( not all that expensive ), use a 1-1 1/8" hole saw, then boring bar to size. Mike

 

[mmcmdl]

really was what I needed, is there something like a trammel-cutter (but perhaps a little more sophisticated and less subject to vibration, etc.) that I could have used in the milling machine?

Yes , there is .

Edit . Thanks Mr Whoopie .

A S&D drill would do the job also as well as a carbide insert drill . Not knowing what you own , you done good .

 

[brino]

The full answer depends on a number of conditions:
1) what equipment you already have (and it's size),
2) how much you want to invest in new equipment to get it done, and
3) the required precision of the result.

...and there's lots of ways to do it.

start a hole with:
-drill-bit, (hand drill, drill-press, lathe or mill)
-hole saw or annular cutter (drill press , lathe or mill)
-trepanning (lathe or mill)

increase hole size and take to precise size with:
-boring bar and or boring head (lathe or mill)

other options:
-water-jet
-plasma cutter

-brino