Is drilling stainless difficult?

This weekend I set out to drill some holes in my stainless and mount some weldless fittings. Used a 18V Black and Decker cordless drill.

Hole #1: Bottom of half barrel for weldless sight glass (Brewhardware).
- 1/8" titanium bit for pilot hole
- olive oil
- Small step bit from brewhardware.com

The first hole went without a hitch. The pilot hole took no time at all and the step bit made quick work of dilating to the appropriate size.

Hole #2: Upper skirt of half barrel to install eye bolt (for securing sight glass)
- same bit for pilot hole, the bit snapped in half before hardly scratching the surface.
- New cobalt 1/8" bit from lowes

Spent an hour with the new bit and couldn't get through. Best I can tell I may be about half way through the skirt. I was making no head way so gave up and went to work on my next hole.

Hole #3: Weldless ball valve on straight sided thin walled stainless pot.
- Same, now slightly worn cobalt bit from Lowes

It wouldn't go through. Again spent 30-40 minutes and couldn't get through and only got a small divot drilled. Also now have a 1" diameter dent because of the gauge of the pot and the pressure I was applying (Standing over the pot with body weight for downward pressure).

So anyone with some experience have insight why my first hole was so easy but then two subsequent tries failed miserably?

Oh I also got a new bit this morning thinking I may have dulled the bit too much and it snapped withing 10 minutes of using it and did very little before breaking.

If it work hardened is there any way to get through now (I never had smoke and the bit never felt hot when I touched it)? My drill is mostly used for hanging pictures on drywall, could I need a more powerful drill?, something with more torque or a gear box? I tried keeping the trigger about half way to keep the rpms low but have no idea how many rotations I was actually getting per minute.

Get a new bit.

Hard to believe it never felt hot.

This is a double post but wasn't sure if anyone would see this question at the end of an old thread. Mods you can delete if needed.

https://www.homebrewtalk.com/f51/drilling-stainless-difficult-261976/index5.html


This weekend I set out to drill some holes in my stainless and mount some weldless fittings. Used a 18V Black and Decker cordless drill.

Hole #1: Bottom of half barrel for weldless sight glass (Brewhardware).
- 1/8" titanium bit for pilot hole
- olive oil
- Small step bit from brewhardware.com

The first hole went without a hitch. The pilot hole took no time at all and the step bit made quick work of dilating to the appropriate size.

Hole #2: Upper skirt of half barrel to install eye bolt (for securing sight glass)
- same bit for pilot hole, the bit snapped in half before hardly scratching the surface.
- New cobalt 1/8" bit from lowes

Spent an hour with the new bit and couldn't get through. Best I can tell I may be about half way through the skirt. I was making no head way so gave up and went to work on my next hole.

Hole #3: Weldless ball valve on straight sided thin walled stainless pot.
- Same, now slightly worn cobalt bit from Lowes

It wouldn't go through. Again spent 30-40 minutes and couldn't get through and only got a small divot drilled. Also now have a 1" diameter dent because of the gauge of the pot and the pressure I was applying (Standing over the pot with body weight for downward pressure).

So anyone with some experience have insight why my first hole was so easy but then two subsequent tries failed miserably?

Oh I also got a new bit this morning thinking I may have dulled the bit too much and it snapped withing 10 minutes of using it and did very little before breaking.

If it work hardened is there any way to get through now (I never had smoke and the bit never felt hot when I touched it)? My drill is mostly used for hanging pictures on drywall, could I need a more powerful drill?, something with more torque or a gear box? I tried keeping the trigger about half way to keep the rpms low but have no idea how many rotations I was actually getting per minute.

Thanks for any thoughts/advise

I've noticed that with my cordless drill and a fresh hi-speed bit I can make quick work of a pilot hole. Once the bit gets worn and the battery fades I switch to a corded 1/2" drill and it goes pretty easily. Not sure why I don't start with the right drill in the first place. Low speed and lots of pressure with oil makes it work best.

I have the same drill. Orange black and decker power drill. I have drilled holes through stainless steel more times than I can count. Where are you buying your bits? Or brand? I bought a basic set of bits at Menards 6 or 7 years ago and have only broken one bit on stainless (about 4 months ago) because the bit was too small and I pressed too hard.

passedpawn said:

Get a new bit.

Hard to believe it never felt hot.

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I agree.. olive oil has a very low smoking point, are you sure you never saw smoke? I used veggie oil for my first few, before I was able to find actual cutting oil. The veggie oil smelled like french fries when the bit was getting too hot.

Also, if you're snapping bits you're pressing way too hard.. get a new (sharp) bit, keep it lubed, and don't press so hard. The pilot holes were the easiest part, reaming them out with the step bit was a much bigger deal (for the big heating element holes I had to do).

The Dewalt bit still hasnt snapped. Just not sure if it still has an edge to cut through. The two that broke were not brands I know or remember off hand.

When I use full pressure I don't even get metal dust in the oil any more. Maybe a little black specs, but doesn't seem like its cutting.

bruin_ale said:

Also, if you're snapping bits you're pressing way too hard.. get a new (sharp) bit, keep it lubed, and don't press so hard. The pilot holes were the easiest part, reaming them out with the step bit was a much bigger deal (for the big heating element holes I had to do).

Click to expand...

Thanks, was begining to think I had too much pressure glad someone confirmed that thought. Didn't see any smoke but was drilling SLOW and taking lots of breaks. Will try again next week with a fresh bit.

Stainless is hard on drill bits. I use a low speed high tork dewalt drill. I start with a small pilot hole and slowly keep increasing drill bit sizes untill i run out of sizes and have to use my step bit. I also use this stuff called boelube i get from work on my drill bits it makes them cut easier and keeps them sharp longer. I also take breaks to let the step bit cool. the hotter they get the faster they dull.

Slow, high pressure, and keeping cutting area cool are the requirements for successful stainless drilling. Water works as well as anything if flowing over drill site to carry away heat from cut area, once the stainless heats up too much it hardens and all bets are off trying to continue to drill opening. For hole saws I use Ocello sponge inside and soak it with a water base coolant, liquid thrown out during cut keeps cut area cool enough to prevent work hardening. If you had help, a spray bottle of water will work wonders while drilling stainless, constant spray of water into cut area will control heat, if you see steam, stop and cool the work down before trying again.

Well I have no idea exactly what you're doing, but i used a cheapo drill bit set from Harbor Freight and I had the first hole drilled in about 10 minutes. The first bit I had was bull (I think it was 1/8") so I stepped up to 9/64 (the next one up). I stepped up 1/8" at a time and 20 minutes later the keg was drilled through.

Installed a bargainfitting fitting, tested it, no leak.

I used WD40 for the lubricant. Worked fine.

MC

I had no problems at all drilling the hole in my keg. I started with a 5/32 drill, then a 1/2 drill, and then I used my step drill up to 7/8.. I used corn oil, and it DID smell like french fries like bruin said.. I'd say the whole process took me about 5 minutes at the most.

I just did a small hole today with a Dewalt Cordless Drill... used a titanium bit for a pilot hole and Irwin Speedbor to step up. I used Dawn as a lubricant and all worked brilliantly. Like many have said - the key is pressure and low RPM's.

Pressure, Very slow rpm, and a good bit is all you need. Even titanium isn't that great, cobalt will work better. Cutting through a keg shouldn't need any oil. It's very thin, with a good drill bit it should not even heat up by the time it's through. I use a very good 1/2" bit to cut the initial hole. It takes less than 30 seconds. Then I use the harbor freight punch set. The punches work great, after a couple holes they do get a little dull, just use a flat file on the edges until they are straight and flat again.

I'm working on drilling the stainless Insinkerator sink trim for a hop spider with no luck. Plenty slow, WD40, never even got hot to the touch, but after 15-20 minutes, no dice. My only thought is a dull bit, it's a semi-old 1/4" Blu Mol but still sharp. The trim is a bit thick, but I'm at a loss. Ideas?

My personal experience from drilling the 3 holes(ball valve,thermometer,sight glass) in my biab kettle with a 50 dollar step bit from lowes, and some lube.

1st hole- 10-15 mins
2nd hole- 35-45 mins
3rd hole- 1-1.5 hours

I dont know what it was maybe the step bit getting dull. But my drill was basicly on fire and the bit was melting the stainless steel. I put a whole lot of ass into it. I personaly understand why some people purchase their kettles pre drilled. But after buying everything seperatly and saving like 150 dollar I would do it again.

If you get the metal really hot you'll work-harden it and it becomes infinitely harder to cut. It's been said many times but bears repeating: SLOW, KEEP IT COOL. Oil, water, whatever, just keep it cool.

Got the holes drilled today. A new drill made all the difference. The b&d battery cell was shot. I was actually drilling too SLOW previously. With my limited experience with drills and reading people saying to go slow, I way under shot. The new drill was set on slow rpm but that speed was still much faster than the old one with a croaking battery. Bye bye cordless. Went through like butter today.

I'm glad you got the holes drilled but just so we don't confuse future readers - there is no problem with using a cordless drill - you just need a good one that is capable of drilling very slow while under a lot of pressure. Dewalts are up to that task for sure and that is what I've used to drill hundreds of holes from 1/8 up to 2 1/8" without any issues. You really do have to go very slow with stainless because if you go fast and harden it you're going to have a long day. Good example of just how slow is with the 2 1/8" hole saw, 87 rpm is recommended - 87!! Oh and cutting oil - if you like your bits that is!!! Sprayon makes a NSF certified cutting oil that I'd highly recommend.

I figured since I saw my old thread resurrected I would throw the experiences I had after reading it in:

Since my original post I've drilled 10-15 holes in flat sided pots and keggles. The best advice was, indeed, to go slowly with a lot of pressure. I used cutting oil and dipped the entire bit into it every minute or so. This was sufficient to cool it.

You should be seeing 'ribbons' of material as the bit cuts, not flakes or powder. This is a good sign that you are moving slowly enough and not over-hardening the metal, as well as applying the right pressure.

I did use a corded drill, if that means anything.

Just for good measure and future readers, I'm pasting in the text on my instructions page on drilling stainless. This is collective knowledge from a couple years of drilling for other people and supporting customers on their own projects.


Drilling stainless steel is a tricky maneuver if you haven't done it before but you'll get through it if you take your time and heed all warnings and tips here.
Lay the pot/keg on its side on a piece of cardboard or old carpet on the floor. Line the interior of the pot/keg with a rag, newspaper or a towel to catch lubricant and shavings for easier cleanup.

The first step is to make a tiny divot or depression at the centerpoint where you intend to drill. A pointed center punch and hammer is preferred but if you don't have one, you can use a 10 penny nail. This keeps the bit from wandering across the surface. We recommend first drilling a "pilot" hole of approximate 1/8". Step bits are not great at making that first piercing cut.
Fill a shot glass or similar sized cup with vegetable oil, chuck the step bit into your drill, dip the bit about half way into the oil, position over the 1/8" predrilled hole and apply a firm pressure when you start the drill. After you reach each new step on the bit, stop. Dip the bit back into the oil and let it drip off before drilling the next step. Don't make the mistake of overdrilling the diameter. The WL bulkhead and any other 1/2" NPT penetrations require a 7/8" hole.
While you're drilling, it's best to have someone help by holding the vessel stable. Hold the drill firmly and even prop the back of the drill against your thigh if you can so that if the bit grabs and tries to rotate the drill motor in your hands, you don't hurt your wrists.

Technique Tips and Tools:
The general mantra for drilling stainless is heavy pressure and slow speed. As the step bit turns against the work, it should be slicing a thin ribbon of material away the entire time. If the bit is spinning but NOT cutting, you run the risk of work hardening the stainless which is wear the bit down almost immediately. One of the biggest problems people have with this job is that their dril does not have enough low speed torque to allow for the pressure required to be applied. In other words, if you push as hard as you should be, some drills bog down. The user will try to overcome this problem by running the drill faster. Stop, stop.... No one likes to admit defeat but you may want to ask a friend or neighbor to borrow their drill. A 12 volt or higher cordless drill/driver that is multiple speed adjustments is highly recommended. The reason these work so well is that their speed adjustability is done with gearing, not a variable trigger squeeze. The low RPM setting provides a LOT of torque while keeping the speed slow. We love the DeWalt XRP series, not that you were shopping for a new drill.

We are being extremely wordy here, but it's important because we've received a lot of complaints about how cheap and dull our step bits are. While they are not the same quality as Klein or Greenlee, those higher end bits would also fail miserably with poor technique and a drill with inadequate torque. If you do not have a high torgue/low speed drill and can't borrow one from somewhere, you'd be much better off finding a plumber or electrician that can use a 1/2" conduit punch on your pot/keg. We have drilled many many holes using these "cheap" step bits and we know for a fact that you can get at least a half dozen holes drilled before you make them paper weights.

Thanks to everyone's advise and the good folks of BrewHardware and Bargain Fittings my pots/kettle are finally pimped.

Low RPM is the way to go for sure but as stated above you need the torque to keep the bit moving. My problems of past were related to faulty battery cell which must have caused lack of torque or my arms were too tired to apply enough pressure.

Here is the drill I bought as a replacement:
http://www.lowes.com/pd_118433-67702-D10VH_0__?productId=1006139

The DeWalt is likely much better. Still the Hitachi however was under $40 and had a speed control dial so you don't have to rely completely on trigger pressure. Other than brewing projects, I don't do a lot of work to need a really nice drill.

I only got a corded drill because this drill had what I was looking for and wasn't much more than a replacement battery. I don't have any application where I would need to be cordless anyway. :cross:

Thanks everyone for helping me get this done.