Cutting Through

[GQT]

I'm modifying my setup, and part of it is making a few holes in pretty tough 2.5 mm stainless steel pots.
I had drilled SS before (very little fun) but never done that on curved surface.
What do you people think is the best tool for the job?

The best way to make a hole in a kettle (or whatever else stainless steel piece) is...
Please comment if there is a way I didn't mention in the poll.

 

[johngaltsmotor]

For a curved surface it's not much different except that you'll want to make sure to use a center punch to make a nice dimple to keep the bit from wandering. Stainless needs plenty of pressure and slow speed, and lubrication helps. Getting it hot makes things worse, you want to make a large chip so that the chip removes the heat. Otherwise the heat of friction is absorbed by the main body and the part you're trying to drill gets hotter (and depending on the alloy gummier or harder).

You could try putting in a small hole and using an electrical knockout punch but most of them aren't going to like that thick of stainless (at least not without a hydraulic puller).

And the hole saw is a bear because on the curve once you break through you've got multiple interrupted cuts trying to toss the saw around (unless you've got a drill press big enough to hold your pot).

The best way if you can afford it or find a friend is a plasma cutter - fast and easy, then clean up the edge with a Dremel grinding wheel if needed.

 

[hottpeper13]

It's ~100$ the Milwaukee unibit. I've drilled out 3 kettles so far, there is a burr that needs to be filed smooth. If you are only going to do one or two kettles take them to a machine shop and swap labor for beer.

 

[PlexVector]

I've found that the titanium bits work much better than carbide, but still a PITA. Go slow and stop frequently to let it cool and relube. just before punch through at each step spin it faster.

 

[GQT]

most of them aren't going to like that thick of stainless (at least not without a hydraulic puller)

Thanks for a great reply John, I honestly was feeling inclined to punches (however with all manual tools I admit I did worry a lot whether this task was altogether doable). From what you say, rather no than yes. Pity. Plasma, no - not that I would know any place within reasonable distance. Sure there are, but might take longer to locate such a place than to drill the hole with whatever is at hand. I'll think about a step bit.

It's ~100$ the Milwaukee unibit.....take them to a machine shop and swap labor for beer.

Errr, well, 100 bucks sounded like a bit more than Meine Frau would swallow. She's already not quite happy about my recent spendings... And trust me in a place I live you wouldn't want to go to a random shop. Places that I know might do well about lathing (which I use extensively) but not other operations.

I've found that the titanium bits work much better than carbide, but still a PITA. Go slow and stop frequently to let it cool and relube. just before punch through at each step spin it faster.

Thanks Sir, looks like step bit is not just the best but the only option left.

 

[kh54s10]

I can't really give this one a vote. I hear that punches are great. I used a very cheap step bit from Harbor Freight. (no budget for better equipment) I went very slowly and had no problems except the step that was closest still left me too tight. I had to grind a tiny amount with a Dremel. That took far longer than creating the holes as far as possible with the step bit. Still, 3 holes took maybe about hour start to finish.

 

[PlexVector]

Thanks for a great reply John, I honestly was feeling inclined to punches (however with all manual tools I admit I did worry a lot whether this task was altogether doable). From what you say, rather no than yes. Pity. Plasma, no - not that I would know any place within reasonable distance. Sure there are, but might take longer to locate such a place than to drill the hole with whatever is at hand. I'll think about a step bit.


Errr, well, 100 bucks sounded like a bit more than Meine Frau would swallow. She's already not quite happy about my recent spendings... And trust me in a place I live you wouldn't want to go to a random shop. Places that I know might do well about lathing (which I use extensively) but not other operations.


Thanks Sir, looks like step bit is not just the best but the only option left.

Check these out: http://www.brewhardware.com/ProductDetails.asp?ProductCode=StepbitCombo $20 These work better than the Milwaukee brand.

 

[iijakii]

A punch is definitely the easiest and cleanest of them all. They're expensive and not necessary, though. I've used them a few times by borrowing ones off of here and Kal's forum. Think I just paid shipping, might've given the guy $15 or something though.

Step-bits work great as long as you have a high-torque, low-speed drill. I've done a good 15 holes with them. When I borrowed my Dad's nice drill they were cake. When I tried using my cheap drills with too-high RPMs they just work-hardened like crazy and didn't go so well.

Personally I haven't tried the holesaw.

 

[passedpawn]

I've used a unibit to drilled many holes (~7/8") for valves and fittings in keggles. I used the expensive bits and they worked very well.

I also drilled the large (1-1/8" I think) holes for elements using a cheap unibit. That was HARD work, took forever. I would not do that again. A friend of mine used a bimetal hole saw to enlarge those same holes and I don't think it was too hard for him. so maybe that's the way to go.

Conduit punches are probably the best solution, Greenlee is usually the brand. They are $$ though, and I imagine one large enough for an 1.5" or 2" triclover ferrule for an element might be $$$.

 

[kombat]

Another vote for the punch here. The cost was very prohibitive, and I only needed a couple of holes, so I found a fellow local home brewer who'd already bought them and had him punch the holes for me in exchange for a few bottles of craft beer.

 

[GQT]

But guys will it be doable at all to use punch and manual tools (i.e., a wrench with long handle) to deal with 2.5 mm stainless steel? 1 mm I would not doubt, but 2.5? The pot looks and feels like it was made to be a tank turret and was sold as a pot by mistake.
In China where I am stationed punches are way cheaper than step bits (although I presume crap quality but at this price I wouldn't care if it lasted for 2 holes only).
Hole saws are the cheapest though.

 

[iijakii]

2.5mm is some serious ****, not sure I've heard of a pot that thick before. I bet a punch would still do it, and that the hardest part will be drilling the hole for it.

 

[JosephN]

Here in Tennessee we call a punch the small shaft similar to a heavy gauged nail that you use to hammer into metal to only leave a small dimple. There is no damn way you're going to use a "punch" for this job, unless there is another kind of punch out there that I'm not aware of. I'm an electrician and we use a thing we call a Manuel Knockout to get the holes that was need for stuff our step bits, aka uni-bits, can't handle. Even for a knockout yours need a hole started and if that's the case you might as well use a step bit unless you need a giant hole. A holesaw is a dumb idea. With stainless or any metal, those saws love to jump or wander. If you want it to look clean and give you a good seal, depends on if you're using weldless or welded. I have used a step bit on stainless steel blank outlet covers, which honestly I don't know how thick they are, but if your kettle is thicker, I still think it will make it though, you'll just have to be patient so you don't burn up your bit. You just need a bit of cutting oil, maybe some mechanics have some, and use that while you drill. Also the "punch" would be great to help your step bit stay in place.

Happy drilling

 

[GQT]

Here in Tennessee we call a punch the small shaft similar to a heavy gauged nail that you use to hammer into metal to only leave a small dimple.

That's all about terminology
This
http://detail.tmall.com/item.htm?id=10621850695
is also a punch.
Dimple first, drill a pilot hole second, make it bigger with a bigger bit or a step bit, then press-cut the hole with this whatever-we-decide-to-call-it.
GreenLee is surely a better option but given its price I'd rather buy a new Chinese punch for every hole I need to make...

I haven't decided yet whether I want to go weldless or otherwise. I think I might try weldless first and see how it works. It will never be late to upgrade the weldless setup to welded, but not backwards. I haven't overgrown the joyful first stage into this hobby so I'm happily toying with whatever equipment I can put my hands on.

 

[Full Throttle]

If you use a bi metal hole saw after you drill the pilot hole take the drill bit out and flip it over or put a piece of 1/4" steel rod in place of it so you don't have the drill bit cutting the pilot hole bigger and wandering around. Makes the process much easier

 

[Bandit-brewer]

Centre punch, 1/8 pilot hole and a stepbit with lots of cutting fluid. Go slow and relube often. I did 9 holes over my 3 keggles in under 10 min. This isnt rocket science.

 

[rudylyon57]

I've done about 4 holes in 1.5 mm material (guess) mainly for 1-1/2" TC ferrules using a bi-metal hole saw without problem. Holes were not 100% round but that was not an issue when ferrules were later swaged through and soldered. With a drill press, low RPM, steady feed and liberal oil I was able to drill each one in about 20 seconds. Dressing holes, swaging and solder took another 5 minutes each.

 

[Dixon9717]

This is what I used. $17 harbor freight View attachment ImageUploadedByHome Brew1445973529.230855.jpg

 

[Riot]

Those cheap step bits work fine if you go slowly. I've done around a dozen holes with the set I have and they are still plenty sharp

 

[jcav]

I used a small drill bit to make a small pilot hole after making a small dent with a punch, but you can use a nail. Then I used my Harbor Freight step bit to enlarge the hole, in my case it was enlarged to 1/2 inch. Then I used the Greenlee punch to make a perfect clean hole in my keggle. You can see the photos in my build thread......

John

 

[Mountainsax]

Maybe this is a stupid question, but I'm going to ask it anyway! If you use a step bit, then how do your grind down the resulting rough edge without work hardening the steel?

 

[cilestiok]

I use a file to remove the burred edge.

 

[PlexVector]

Maybe this is a stupid question, but I'm going to ask it anyway! If you use a step bit, then how do your grind down the resulting rough edge without work hardening the steel?

I t doesn't take much filing with a hand round file, took me less than 30 seconds to knock the edge down.

 

[iijakii]

I think I just went from the inside and ran the stepbit without pressure to sorta grind down any of the edges that flared in. Worked great, didnt have to file a thing. Probably hardened it a bit but was done drilling by that point so who cares.

 

[Mountainsax]

I use a file to remove the burred edge.

I t doesn't take much filing with a hand round file, took me less than 30 seconds to knock the edge down.

I think I just went from the inside and ran the stepbit without pressure to sorta grind down any of the edges that flared in. Worked great, didnt have to file a thing. Probably hardened it a bit but was done drilling by that point so who cares.

Excellent! I have been wary about using a step bit (even though everyone says it works) because of the burrs. Sounds like a non-issue. I think I'll try that first before I buy knockout punches.

 

[Mountainsax]

Another question; if you could get 9/16 and 13/16 knockout punches for <$25 each would it be worth it? Still would need a step bit to do the 1 1/4" holes for heating elements and starter holes.

 

[Rcbandl]

The easiest answer is how much you want to spend. The quality of the hole and ease of use pretty much ramps up with the cost of the different tools.

But any one of the options will work just fine

 

[poptarts]

http://www.amazon.com/dp/B002LFGKOW/?tag=skimlinks_replacement-20
More people need to start using this instead of step bits for cutting holes in pots, it cuts clean and fast.

 

[Rcbandl]

Maybe this is a stupid question, but I'm going to ask it anyway! If you use a step bit, then how do your grind down the resulting rough edge without work hardening the steel?

One recommendation I have seen alot of and it worked for me is drill down to right before the size you want goes through and finish the hole from the opposite side. Results in a minimal bur.

 

[PlexVector]

http://www.amazon.com/dp/B002LFGKOW/?tag=skimlinks_replacement-20
More people need to start using this instead of step bits for cutting holes in pots, it cuts clean and fast.

I was wondering about those. I may give it a try on my next one.