Best way to cut a hole in stainless?

[heus]

I need to cut two holes approximately 1 1/4 inches in my 22 gauge steamhood for the inlet and outlet plumbing. What is the best way to make the holes? Is there a special bit for stainless?

[sapsucker78]

I am no expert on this but the guy that does my stainless work always stresses that you do not use any type of blade that is any type of normal steel. The carbon in the blade will inbead in the stainless and make your stainless rust! He says any type of cutting or scrapping on your stainless with carbon steel will do this.

[Rossell's Sugar Camp]

I would use a hole saw for something that big. It will cut a nice perfectly round hole.

[Dennis H.]

Use a greenlee hole punch, They are used buy electricians to puch holes into boxes for stuff like conduit.

You 1st need to drill a hole, something like a 1/4" then put one half of the punch on one side of the metal and the other half on the other.
Use a wrench of socket and ratchet. Punches a nice round hole the size of your liking.

[maplwrks]

Like Dennis said---a Greenlee punch

[Toblerone]

For rough holes, I have used a dremel cut-off tool or a sheet-metal nibbler, but the holes were very rough and not a perfect circle.

[RileySugarbush]

For lot's of holes, a greenlee punch is best. That is what I have used to make drop tube pans. Look to borrow one or maybe rent. For only a couple, a Unibit is another good choice. Expensive but very handy.

http://compare.ebay.com/like/200606939920?var=lv&ltyp=AllFixedPriceItemTypes&var=sbar

[Squaredeal]

Use a bi-metal hole saw. I have a Greenlee punch set, but I think it only goes up to 1" or so. I have drilled 2" holes with a bi-metal hole saw on stainless that has been outside for 8 years. Looks pretty much the same as the day I drilled it.

[maple flats]

Greenlee is the best. If you have a sheet medal shop in your neck of the woods, they will make the holes. I borrowed one from my local tin shop but they are good friends. Greenlee punches go much larger than 1". If you only need 2 holes don't buy the greenlee (Greenlee punches are expensive), the tin shop will charge less than buying. Maybe try giving them a qt of syrup.

[maple flats]

If you don't go the Greenlee route, drill a hole about 1/2" using a high speed drill and have a block of wood backing it tight. After drilling make a circle surrounding the drilled hole just slightly larger than the desired final size. Next carefully cut from the hole to the circle in little pie shaped slices around the hole (make it in 10 or even 12 slices, roughly equal in size. Then carefully bend each tab you made inward and bend it all the way back 180 degrees. Then put a block of wood on the outside and hammer each tab flat. You should now have a fairly neat 10 or 12 sided hole with no exposed raw edge.

[Jec]

I don't know about a hole saw. I bought a 4" one for my blower and it dulled before it even got through the job. It couldn't even cut through thin stainless. I wouldn't recommened it for holes in metal.

[warners point]

I used a Lenox Unibit/ Step bit. $50 at Viking Electric. They are razor sharp and go through 18 ga. stainless with little effort. Drill a pilot hole first and just let the bit do the work. I've done over 150 holes on one bit. The great thing about the step bit is all the differnt sizes on one bit and it cuts to the outside diameter of the pipe.

[Rossell's Sugar Camp]

You have to use carbide tipped hole saws for stainless. Anything else dulls out really fast.

[markct]

a standard bi metal holesaw will cut stainless fine, the key is steady pressure, cutting oil, and most importantly low speed. you have to remember that the larger the diameter the bit the slower it must turn to prevent overheating the teeth tips, i have drilled holes of as big as 4 inch in 304 stainless 1/4 inch thick with a holes saw, on that job i drilled about 10 holes with the same holesaw, and still have that holesaw and have used it many times since. if you destroyed a holesaw in one hole in stainless something was wrong i think.

[lew]

I agree with Markct, slow and lots of cutting oil. Not to out do you markct, but we used a standard bimetal holesaw big enough for the outside diameter of a 2" brass pipe. We cut the hole through a 1" thick plug from a milk tanker to make a reducer. I think milk tankers are 3". Any way, it took a lot of time and cutting oil, but we made the hole with no damage to the hole saw.

[maple flats]

Hole saws will work too. I was in the outdoor boiler business for years. On occasion we had to cut out boiler tubes and replace them. This was in SS and we sawed thru the welds around the tube. They are right, lots of cutting oil and turn it slow. Ideally not over 300 RPM for 1.5". We used 150 RPM drilling 4 1/8" holes to replace the tubes. For your SS, again you'll do best if you support the SS against a block of hardwood when you drill if you chose that method. Without a backer your greatest risk at damaging the hood will be as the saw first starts breaking thru.

[markct]

one tip i should mention if you are drilling metal thicker than about 1/8 with a hole saw it helps to drill a hole or two about 1/4 inch dia just inside the outside diameter of the holesaws cut, that helps to let the chips out of the cut and makes it go much better

[Maple Hobo]

Not sure how thick of metal it cuts but I've worked with a hole cutting die cutter. Basicaly you drill a centered hole for the threaded shaft, 1/4" TO 1/2" and the cutter has two halves that close together as you turn the bolt like a nut drawing up. The one side draws into the other side and basically cuts a round hole like a paper punch. It doesn't buckle the sheet metal or make ragged edges.

I think they make a variety of shapes that will cut this way from circles, squares, triangles, ovals and even stars...lol

It should easily cut any pan i've seen in use so far.

[RileySugarbush]

Not sure how thick of metal it cuts but I've worked with a hole cutting die cutter. Basicaly you drill a centered hole for the threaded shaft, 1/4" TO 1/2" and the cutter has two halves that close together as you turn the bolt like a nut drawing up.

That is a Greenlee punch!

[johnallin]

Hues, I've used a step drill bit on stainless with great results. When I had the 1/2 pint I used one to drill a hole in the pan for a thermometer.
Clamp your stainless to a piece of 2x6 and you'll be amazed how good it goes. Your only removing an 1/8" at a time...
Check this link, one on Ebay for $13 with free shipping.
http://www.ebay.com/itm/1-4-1-3-8-Titanium-Step-Drill-Bit-10-Steps-M2-3-8-/290551380488?_trksid=p3284.m263&_trkparms=algo%3DSIC%26its%3DI%26itu%3DUCI%252BIA% 252BUA%252BFICS%252BUFI%26otn%3D21%26pmod%3D180644 878457%26ps%3D54

[Jeffery G.]

Jason,
If you didn't get the job done yet, and can bring the hood over to my house, I will cut the holes for you with my plasma cutter.