hole saws

[Jayare123]

I have a guy wanting me to do some conversions to a stainless cheese making tank so that he can make beer in it. Need to add several 2" 3" 1.5" and 6" fittings to it. Being that it needs to be sanitary, im thinking a hole saw would be the best way to make holes so it's a nice edge to weld the fitings to. Would be no fun making it nice and smooth and sanitary with a boogered hole. So question is what hole saws should I be looking at? It's 16ga stainless. I'm just assuming that the standard saws at Home Depot may not be sufficient for making more than one hole, maybe I'm wrong?

[Ltbadd]

A picture of this tank would be nice, how will you power the hole saw? Using a hand drill on the 3 and 6" I believe would be tough.
I would definitely use a good cutting fluid such as Tap Magic

HERE is a good guide from Lenox, and another from Grainger

[aametalmaster]

The key is the speed of the drill. You want a lower speed on the bigger saws...Bob

[Jayare123]

You say a hand drill would be tough. What do you propose I use then? Mag drill isn't really an option being its stainless.

[ryanjones2150]

ROTO-broach would be better. Not cheap though, especially in the big sizes. Do you have experience cutting and fab on stainless? 16ga isn't too awfully skookum, but it'll put the hurts on a hole saw, especially a cheap one. The right cutting fluid is a must.

[Jayare123]

Skookum? I've got a decent amount of experience with thin stainless. Built food service equip for 5yrs. Pretty much everything in a commercial kitchen. And I've worked on the road installing sanitary piping. Never had this exact scenario tho. Ran a bunch of .065 wall tube but never had to make new holes in tanks for that. Only time we had to make holes in tanks was with the sched 10 so there's enough meat to make up for scraggly cuts with filler on that. But this is gonna be no filler. Need the hole real nice so it can be welded no filler.

[Jayare123]

So I got a 6" Milwaukee hole saw and tried it out on a sheet of 12ga. No beuno. Drill is smoking and the saw isn't making much progress. I need some ideas for making these holes y'all

[MAC702]

...Need the hole real nice so it can be welded no filler.

Why the requirement to weld it without filler? And are you even able to match a hole saw to a fitting that precisely even if you COULD drive the hole saw cleanly, which I doubt? I've used hole saws up to 6-3/8" and would not attempt it on this.

This sounds like a plasma cutter job to me, with really good jigs, and the proper filler rod for the welding.

[Jayare123]

I've got filler. I know how to use it. If I have to I will. But it'd all come out nicer if I don't have to. Major issue with plasma cutter is I don't have one. I can borrow one. Idk if my air compressor is up to running it tho

[Metjunkie]

I second the plasma cutter idea. It shouldn't be too difficult to rig something up for cutting the hole. I used a 2hp, 20 gal. Campbell Hausfeld compressor with my plasma for quite awhile until I got my 60 gal. Ingersoll Rand. Worked just fine. You wouldn't be running the compressor continuously, so even a smaller one should be fine.

[Ltbadd]

It's going to take a lot of torque for that 6", you have to have the best available tool which may be a carbide tipped hole saw, an electric drill (not cordless) and a good cutting fluid.

[ryanjones2150]

Take your project to a water jet cutter. Generally charge by the inch, but it would clean, perfect and ready to weld.

[MAC702]

Another reason to plan on filler is because you'll want a nice bead on both inside and outside for both appearance and cleaning purposes.

And are you cutting on a flat or curved surface?

[Jayare123]

Water jet is no go. Tank is existing I'm just modifying it. Looking like I'm gonna try and borrow a plasma cutter. The 6" hole is on top of the tank which is mostly flat. The rest of the holes are going through the sides of the tank so on a curved surface.

[Oldgrandad]

Milwaukee Hole Dozer Is my hole saw of choice and I use rapid tap cutting fluid. We do holes in stainless all the time. For doing sanitary, I would scribe the hole first, hole saw it a tad under. Then use a barrel sander to bring the hole to my line. I would use whatever tube or pipe is your welding to the tank as my template for scribing after couping it to match the tank.