Stainless Woes

[trentonmakes]

Any ideas how to enlarge a hole in stainless?

I need 1 3/4 clearance for the largest application of a fire rated seal.

The largest step bit I found is 1 3/8,and stainless tends to burn them up.

I thought of maybe clamping 2x4 and using a holesaw.

Looking for ideas other then plasma cutting, though that would be my preferred choice or simply cutting out a piece of stainless and weld it in.





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[mike13u]

I would clamp to a piece of wood backing so you can locate and pilot an accurate center, then use a carbide tipped hold cutters available from Klein, Greenlee, Champion or Morse. They look like this:
http://www.amazon.com/dp/B00204FVCQ/?tag=atomicindus08-20

 

[PCustoms]

For a one off, draw it out with a sharpie and die grind to size.

 

[racingtadpole]

How thick is it? If its under 16G you may be able to use a decent quality chassis/knockout punch on it if you have access to both sides.

 

[rlitman]

If the hole is at least 3/4" to begin with, I could fit my nibbler in there and cut to my heart's content, though the edges won't be hole saw smooth.

 

[trentonmakes]

I would clamp to a piece of wood backing so you can locate and pilot an accurate center, then use the a carbide tipped hold cutters available from Klein, Greenlee, Champion or Morse. They look like this:
http://www.amazon.com/dp/B00204FVCQ/?tag=atomicindus08-20

That's about what I was thinking.


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[trentonmakes]

We tried a punch and broke it lol
It only bites one side of the hole, it slips/slipped??? Dunno
Great for making a hole, not so much with existing holes.

It's likely right at 16g, stainless hood you see in commercial kitchens.

Retrofitting the pipes or what have you, any hole needs to be filled/welded. We use a fire rated seal which is basically a nut and washer.

No access to welder or air unfortunately.

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[ddawg16]

16g Breaking a Greenlee knockout? I find that hard to believe.

I'd use a die grinder then. 16G is pretty light stuff

 

[trentonmakes]

I stand corrected, it was 24g

I'll snap a pic of the knockout tomorrow. The stainless on some of these is pretty hard.
I was told for drilling, and seems to work well...
New/sharp bit, dip/spray with water to keep cool, only use it for stainless, no wood or other metals...


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[dr_clyde]

24 gauge is really thin, roughly .020". If it was me, I'd use a sanding/grinding drum on a mandrel.

Like one of these:



These work great for enlarging existing holes. Just mark a line around where you need to stop, then sand to the line. I do this in stainless all the time.

Available at your local welding or industrial supply.

 

[Slowgsr]

The carbide tipped drills work Great, I have a set, for emt 1/2 - 2 (7/8" to 2 3/8")
I use them for everything including when I have to drill stainless switchgear - my hydro ko kit will punch stainless no problem. A high quality hole saw will work just fine with lubrication

 

[sqznby]

For such thin material, I'd recommend these. They cut very well and as long as you maintain them they will last a while.
http://www.lenoxtools.com/pages/bi-metal-speed-slot-hole-saws.aspx

 

[trentonmakes]

Here's the punch, you can see the bent stud and the chipped cutter where it grabbed one edge of the existing hole.


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[yaidunno]

Whats with the bent mandrel in there? I hope its not what you used.

24 gauge stainless will not put up that kind of a fight. I would guess that the male die collided with the female. If those dies have a reasonable cutting edge, and are aligned properly, they will go right through 24 ga. stainless.

 

[trentonmakes]

That was the end result, lol

Your correct though, I think they only caught the lip on one side and the dies mashed together.
Which is why I asked about an easier way to enlarge pre-existing holes.
TBH, I'm not 100% on the gauge, other than it states 24g minimum for commercial hood.

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[gungatim]

I have cut holes several times in stainless kegs, use HF unibit and finish with die grinder. re-passivate if it gets too hot...

 

[mrolds88]

I would think clamping a 2x4 behind hole and use a hole saw. Keep it lubed.

 

[sqznby]

How hard are you going with those bits? SS needs to be cut slow and steady.

Try the hole saws I posted, I can bet you'll be more than satisfied with the results. It doesn't matter the thickness, they eat that sh*t up like a hot knife through buttah.
They're available at most hardware stores to.

 

[trentonmakes]

I'm liking them, just need to get approval from the top.
They've used them in the past, but for some reason they now use step bits???
It's not an every day need, but it would be nice to have the correct tool for a job when needed!

Big Thanks

OK, I thought you were Mike 13, lol
But yes, those Lenox hole saws would be my 2nd choice! [emoji106]

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[Lassen Forge]

If you're going to cut it with any kind of drill, you need stainless cutting fluid and at *least* carbide tips... diamond drills are spensive as heck but they work as well.

 

[dr_clyde]

You don't need fancy cutters to do work on stainless steel. I work almost exclusively in stainless, and HSS cutters, drills and plain hole saws work fine. You DO need to use the proper feeds and speeds, and the correct cutting fluid. I do not understand why people think they can work stainless the same as steel. They are very different metals with very different properties.

 

[plow]

We tried a punch and broke it lol
It only bites one side of the hole, it slips/slipped??? Dunno
Great for making a hole, not so much with existing holes.

It's likely right at 16g, stainless hood you see in commercial kitchens.

Retrofitting the pipes or what have you, any hole needs to be filled/welded. We use a fire rated seal which is basically a nut and washer.

No access to welder or air unfortunately.

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Sounds like you're installing a wet chem system?

 

[plow]

BTW, if you're mounting the Beco seals, 1-1/8" should work. That would mean your step bit will work.

 

[lilredex]

These were cut with a bi-metal hole saw, but I had the advantage of using an old SB lathe on a very slow speed. Material is 18Ga SS, I believe.

 

[trentonmakes]

Sounds like you're installing a wet chem system?

Lol!
Yupp

The pipe for the powder is a bit larger than the 3/8-1/2in for wet chem.

They had problems enlarging a hole for one of the seals to fit. Lol

I was running conduit at the time, but I was the one who ended up using a pretty worn step bit, getting it to fit.

I think that was the biggest issue, the bits, even the drill bits, (well most), were pretty worn out.

I'm just looking for an easier way to enlarge an already existing hole. Seems anchoring a 2x4,and using a hole saw is likely the best method, or a new step bit.
Lol

I looked at new step bits and the size wasn't large enough and they're pretty pricey. The largest hood seal is 1 and 3/4in.

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[Zartan]

Bridgeport and trepanning tool?