Keg Drilling Pilot Hole Problems

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maltymike

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SO I have been trying to drill the hole in my keg to put in my valve.

I went out and purchased a step bit because I heard it was slightly easier.

so it was time to go and I have my 18v dewalt cordless drill some mineral oil to use as cutting oil, and a whole bunch of bits for my pilot hole..

well after an hour of getting nothing more than a dent, and about 5 drill bits shattered, i decided i would just try the step bit by it self.. after about half an hour of that i had a little dimple and decided i must be doing something wrong so i stopped.

so I researched, and bought 2 Cobalt Steel bits to use.. well the first one seemed to work, i actually saw some sort of metal bits accumulating but that stopped quicker than it had started. after about 10 mins an a tiny little dimple inside the larger dimple it shattered on me..

everyone says mid to firm pressure, sooo.. but it broke..

so i have 1 more, slightly bigger cobalt bit im trying to make the pilot hole with but its just not working..

I checked a lot of threads and no one seems to be having the same problem I am having... am i really just missing something here, or is my keg made of super stainless. (its a newer miller lite keg with the locking safety clip on the inside of the keg, this one)
 

LooyvilleLarry

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I can tell you that you need to go s-l-o-w. I had mine done in less than 10 minutes. My cheap a** Harbor Freight step bit ate it up.
 

Anthony_Lopez

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It sounds like you are almost there. What it sounds like you are doing is "work hardening" the stainless. This happens when you overheat the steel. What I suggest doing is running the drill at a medium speed, and then stopping for a few seconds to let it cool. If you are making the cutting oil "bubble" or "boil and steam" you are going too fast or not letting it cool enough. The first keg I did I was drilling WAY TOO SLOW, and work hardened the hell out of it. The next day I went to town on it with a faster speed. I also use a CNC coolant when I drill mine so I can blow right through them. I can drill 6 holes (2 per keg) in about 10 minutes now that I figured it out.

Also- Drilling stainless is not the easiest tasks in a machine shop. We actually try and avoid it as much as possible and outsource most of our stainless needs to cut down on equipment costs and shop time/labor.

I'm drilling out some kegs tomorrow. Maybe I'll make a video of the speed and technique I use.
 

davebl

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I use a lenox hole saw from Lowe's. goes through a keg like butta..

just keep LOTS of pressure on the drill and go slower-medium.
 

beerthirty

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Using a drill bit on hard materials requires slow speed, firm pressure, and lots of oil to keep it cool. If the bit gets too hot to touch it's too late for that bit. If the oil starts to smoke stop and add more oil. A bit cuts into hard material easier when its turning slow(less than 200rpm). If the outer edge of the cutting tip is at all dulled the bit will not cut. Anthony is correct about stainless be very hard on equipment. Cobalt(the material not the brand) is one of the best materials to make drill bits out of but its is harder than steel so shattering is a strong possibility when sideloaded. Sideloading is easy to do using a hand drill. I suggest a new bit, oil, and beware sideloading.
 
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maltymike

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Well the oil never smoked bubbled or anything.. I never noticed anything getting hot, it just seems like nothing is happening at all.. I guess i can try and going a little faster.. maybe i am going too slow.... and yes.. the drill bit is cobalt material, not brand..the brand is rigid..

any other ideas?
 

tipicreeper

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With all due respect, I've done worse things...
Is the bit spinning in the right direction?
Cheers
-David
 

Anthony_Lopez

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Honestly- It sounds like you've already work hardened the spot you are drilling, so trying a slightly faster speed shouldn't really hurt anything.
 

tipicreeper

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I agree Anthony.
Try moving to another area on the keg. Use a very small sharp bit for the first pierce. (1/16" or under) Medium speed, lots of oil. Then open up the hole in stepped increments. Once SST hardens it is a royal b*tch. Good luck.
 
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maltymike

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well, im definitetly going forward.. and I guess its hardened.. the bit was working for a while, but now i cant seem to get any fragments coming off the keg. the bit just spins, makes minimal metal grinding noise and nothing..

there is a tiny impression on the inside of the keg where I have been drilling...

I would move to another spot but i am worried because i believe i am more than half way through this spot and I am worried about it opening up somehow...

this sucks
 
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Try smacking a thin nail through the dent. Once you have some sort of hole it goes a lot easier with the step bit. I gave up on the small bits. Kept breaking them.

I used a 3/16 bit and drilled with the drill on slow speed. I gave the area a slight dent first so there was more metal that the 3/16 bit could grab.
 

tipicreeper

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+1 Once you have the pilot (any size) the rest is cake.
I am assuming you are drilling for a 1/2" coupling. (about 1")
you can try moving 3/8" off center an try again that wat the finish hole takes out your hardened dimple.
The pilot is 80% of the battle.
 

Anthony_Lopez

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I'm not trying to start a debate here, however I have to respectfully disagree with you, Denny. Step bits will not be as sharp as a standard "single size" bit. Step bits are great in a crunch, and work well for an all around bit, but for drilling pilot holes, a good cobalt bit is going to be 100 times superior. Step bits also don't remove material as efficiently as a standard bit, and can cause for larger issues when trying to make a "pilot" hole. Just my 2 cents from working in the machine shop at work.

Drill your pilot hole with a good bit (or finish in the OP's case) and then start opening up with your step bit.
 

G-E-R-M-A-N

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I'm not trying to start a debate here, however I have to respectfully disagree with you, Denny. Step bits will not be as sharp as a standard "single size" bit. Step bits are great in a crunch, and work well for an all around bit, but for drilling pilot holes, a good cobalt bit is going to be 100 times superior. Step bits also don't remove material as efficiently as a standard bit, and can cause for larger issues when trying to make a "pilot" hole. Just my 2 cents from working in the machine shop at work.

Drill your pilot hole with a good bit (or finish in the OP's case) and then start opening up with your step bit.
x10000 Cobalt is the way to go when drilling stainless. If you have a drill press with cobalt, your almost unlimited.
 

conpewter

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I don't bother drilling a pilot hole. I just use the step bit and a drill press. (and some sort of lubricating oil) Not saying it is right or the best way, but it works for me.
 

Anthony_Lopez

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I'm not saying that doesn't work, but you will wear out your step bit a lot faster without drilling a pilot hole. Also, I'm giving advice assuming that people don't have access to a drill press.
 

harley03

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I used a step drill bit from harbor freight when I drill mine. The trick is to go slow and apply steady pressure. I can drill a hole through the keg to size within several minutes.
 

Anthony_Lopez

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I think the problem is that when people hear, "Go Slow" they are going far TOO slow and work hardening the stainless. I'll take a video tonight when I drill one of my kegs.
 

conpewter

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Video would be great. I did screw up the large harbor freight bit when drilling out a 1.25" hole for my electric elements. (not the tip, further up)

Also work hardening doesn't have anything to do with heat, it is all about just pounding on the thing etc. Just take a piece of soft copper and pound on it for a while, it'll harden up without any heat.

Edit: My other tip... don't drill near the seam on the keg. I think this is how I screwed up the large bit. It may be harder near that seam.
 

Figbash

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A good cobalt drill will go through stainless whether it's work hardened or not. It sounds like you may need to get your drills from a different source since imported (Chinese) drills are pretty much worthless. When you try it again, make sure to use lots of pressure and a VERY slow RPM. Also be sure to wear safety glasses, no keg is worth losing an eye.

Tom
 
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maltymike

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Well I have bad news and good news...

The bad.. I broke my second cobalt bit... The good news... well I broke my second cobalt bit...

When the bit broke, I was just about ready to do my best worlds strongest man impersonation throwing the keg as far as i could.. (my estimates are around 3-5 feet) but then i saw the broken bit lying on the floor in front of me...and I felt something kind of weird in my head. I now know it was an idea..

the bit still had the sharp point intact, but was now much smaller.. when i inserted it.. uhh.. into my drill the tip stuck out less than a half inch.. I figured this would be impossible to break.. and I was right.. I was able to use so much more pressure and the bit tore through the keg with minimal effort.. took about 5 mins after i switched to the broken bit...

The step bit went pretty easily as well.. that's where i saw my first smoking oil, and i could tell it was putting alot more stress on my drill, but no major problems there besides the extremely annoying ringing sound.

I filed and sanded the hole, and my bargainfitting worked perfectly the first time.. I couldnt believe how easy it was..

Im happy there was a happy ending...kind of.. but thats a whole different story..
 

BargainFittings

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Good the hear this ended well.

I'm going to go with side loading as the problem with the shattered bits. Hand drilling metal is hard on them bits and just a bit of torque with the bit offset will snap them like a twig.

Its also gets nasty with the step bits when a bit of steel case hardens and rips a chunk out of it when it snags the bit.
 
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