A tip for those buying Step Bits / UniBits / keggle drill bit

[dallasdb]

Maybe I was doing it wrong but I drilled one whole and it ate up 3 Harbor Freight step bits.

I tried low speed and high speed it just wouldn't go. I used heavy weight oil to lubricate as well. It seriously only cut to the next step of the bit when the keg got red hot.

I'm taking them back to HF to have them replaced. One hole and all 3 are FRIED!

 

[Bobby_M]

Definitely a technique issue. Your drill doesn't have enough torque or you're not using enough pressure. I've used a Chinese import step bit to drill a 7/8" hole in 1/4" thick stainless plate and still got 9 keg holes out of the bit.

 

[dallasdb]

Definitely a technique issue. Your drill doesn't have enough torque or you're not using enough pressure. I've used a Chinese import step bit to drill a 7/8" hole in 1/4" thick stainless plate and still got 9 keg holes out of the bit.

Definitely wasn't a pressure issue, I was pushing the bejeezus out of it.

Not sure about the torque. It is a corded Makita drill with a switch to make it a hammer drill and it is HIGH SPEED more than low speed.

What is the appropriate drill to use?

The issue I was having is the bit didn't seem to grab the steel in between the steps. For example, it would grab and rip through a layer then sit in between the two sizes (steps) and just spin freely. I found the best technique was to drill and get a bit to grab. Then switch to another step bit with a smaller increment, let that grab then switch back. It was almost as if the steps were to big because they wouldn't grab from step to step on the same bit.

 

[Jaybird]

Slow is the key with stainless!

 

[dallasdb]

Slow is the key with stainless!

I didn't get that memo!

I definitely wasn't going slow. After the first few efforts came up short I tried blasting through the hole.

A few times I was going so fast the bit would slip in the chuck.

 

[Bobby_M]

Going slow is important and that's why corded drills are usually the culprit. Most corded drills have very low torque at low speeds so when you're sitting at the proper speed, the drill stalls out. I don't even like seeing the bit turn one revolution without making a cut. Spinning it fast work hardens the stainless in 2 seconds and it doesn't matter how many more bits you buy or what brand they are at that point. Now it's time to get a conduit punch.

 

[dallasdb]

Conduit punch, or a different drill? I think I would use a different drill more!

 

[Golddiggie]

I use an 18v DeWalt cordless hammerdrill for mine. I also set it in the LOW speed range (of three) which goes no faster than 500rpm. Even then, I've sometimes had an issue IF I went too fast (rpm and trying to do too many steps at a time). I've found that things go quick up to about 1/2" or maybe a step (or two) above that. Then you REALLY need to go slow and make sure you keep everything cool. I might even use my floor drill press for the next keggle I drill (goes down to 300rpm). Or just use the cordless drill at <1/2 speed in the low range.

For a conduit punch, the ones that use the hydraulic driver are stupid easy to make holes with. You just make a 1/2" hole, insert the punch after setting the shaft up on the driver. Pump, pump, pump, PING!! You have a nice 7/8" (or whatever size you need to make) hole.

Which to get depends on how many holes you see yourself needing to make over the long term. If you'll only use the punch a few times, then never again, get the drill. You could, also, get the punch, use it as you need then sell it to someone else (who needs it and doesn't want to get a brand new one). The ones that use a wrench to punch are cheaper than the hydraulic driven ones. I got that one mostly so that I'd never have an issue going through stainless (up to 3mm thick ).

BTW, IME/IMO, the HF Ti coated bits are crap. But you should have gotten at least one hole per bit. Actually, you should have gotten at least one keggle drilling per bit.

 

[Jaybird]

Okay guys I am going to give up a little stainless secrete........Use vinegar for your carbide coolant when drilling stainless. It will keep it from burning the edge of the hole and keep the bit cooler... They will drill like butter.


Cheers
Jay

 

[Bobby_M]

I'll have to try that Jay. The truth is, ANY liquid coolant is better than none and I would even contend that proper pressure/speed is even more important than any coolant at all. I can easily drill ten 7/8 holes in a keg with these "crap" bits.

 

[Bobby_M]

Conduit punch, or a different drill? I think I would use a different drill more!

Well, yes, a nice DeWalt Lithium 3AH hammer drill cordless would be a nice xmas present to yourself. The issue here though, if I'm assuming correctly, is that you've burnt up a few bits on the same hole already. The only way to get further if you haven't gotten to your desired hole size is to avoid that work hardened edge entirely. A conduit punch would do that for this particular hole. If that hole is already done.... disregard. Hmm, well a conduit punch/die set is still a pretty awesome thing to have in the toolbox.

 

[biertourist]

I bought the TiN coated ones at Harbor Freight... the hardest part was finding one that is 1.375" dia for the heating element installs.

That's the biggest I'd want to go with a unibit, too. The torque has to be pretty scary for a 1.375" hole. -I went with 2" tri clamps to use the stilldragon element protector solution so stepbits were "out" as an option to cut the holes. (Hole saw in a drill press worked great, though.)


Adam

 

[biertourist]

I used bobby's step bit just last weekend with an 18v LION drill and cutting oil and it worked just fine. Running the step bit from the inside out after getting the hole to my desired size deburred the hole in 1/2 a second, too.

The REALLY tough part was applying enough pressure to get the pilot bit started. I broke two metal bits and 4 MM bit was just too big to start the hole so I bought a proper carbide bit to make the pilot hole and the step bit did the rest.


Adam

 

[MrNatural]

That's the biggest I'd want to go with a unibit, too. The torque has to be pretty scary for a 1.375" hole. -I went with 2" tri clamps to use the stilldragon element protector solution so stepbits were "out" as an option to cut the holes. (Hole saw in a drill press worked great, though.)
Adam

How do you like the stilldragon parts?
Was looking to go that way myself, but had assumed the 2" triclamps used 2" "pipe" and the clamp fitting was bigger.
The actual ferrule uses 1 3/8 hole?
Have hole saw that size and might even get lucky with Greenlee punch set - gotta go track it down and find out.

Dale

 

[biertourist]

How do you like the stilldragon parts?
Was looking to go that way myself, but had assumed the 2" triclamps used 2" "pipe" and the clamp fitting was bigger.
The actual ferrule uses 1 3/8 hole?
Have hole saw that size and might even get lucky with Greenlee punch set - gotta go track it down and find out.

Dale

You're assumption is correct.
I LOVE the stilldragon option especially for the price (still expensive but the best value TC stainless and safe option) but they really stick it to you on the shipping.

The other problem is that it ships with 3 copper "blade" connectors and if you actually use them, even with the shrink tubing and even after bending them at a 90 degree angle they can easily ground out on the inside of the TC and create a very scary and potentially deadly situation. Both hot legs had grounded out on one of mine. -I replaced the 2 hot blade connectors with a proper plastic coated one and then applied 2 wraps of shrink tubing just to be safe. -Use the copper blade connector for the ground strap but don't even THINK about it for the 2 hot legs.

I borrowed a 2" green lee punch, but it makes a hole that's WAY larger than 2" so choose your punch size carefully...

Adam

 

[MrNatural]

Good info, thanks. Will need to watch assembly closely.

Sounds like you borrowed the conduit sized punch, which is the set I have.

1/2 inch pipe punch-- > 7/8 inch hole
Good for 22mm control box stuff.
3/4 inch pipe punch -> 1.115 inch hole or approx. 1 3/32 inch hole

1 inch pipe punch -> 1.362 inch hole or approx. 1 3/8 inch hole
Which would be perfect for standard element coupler.

1 1/4 is "almost" 1 3/4. Reckon I could use that and the butt-weld adapter trick to dimple it out???

OSH had smoking deal couple weekends back. Anything Milwaukee 50% off and no sales tax. Picked up the large hole saw set and couple extra 2" bits. But then I'd have to rig up cradle/ratchet strap jig on drill press for one stinking hole.

Or...... buddy has lathe I could chuck the hole saw in and use horizontal feed at looow speed, and clamp it up to square bottom and won't need to fab a cradle.
Anyone heard of doing it that way?

Dale

 

[Cioffi]

Going slow is important and that's why corded drills are usually the culprit. Most corded drills have very low torque at low speeds so when you're sitting at the proper speed, the drill stalls out. I don't even like seeing the bit turn one revolution without making a cut. Spinning it fast work hardens the stainless in 2 seconds and it doesn't matter how many more bits you buy or what brand they are at that point. Now it's time to get a conduit punch.

Okay, so I used a Harbor Freight step bit to get a 1 1/4" hole in my keg for an element. I can't get the hole bigger than 1" and the bit started burning the stainless, even with plenty of lubricant. So, based on Bobby's comment above, is there any way other than a punch to get the hole bigger? I was ready to buy another step bit, but if the metal is burned to the point of where a bit won't cut it, what then? Would a grinder work? Something like a grinding attachment on my Dremel?

 

[Golddiggie]

Okay, so I used a Harbor Freight step bit to get a 1 1/4" hole in my keg for an element. I can't get the hole bigger than 1" and the bit started burning the stainless, even with plenty of lubricant. So, based on Bobby's comment above, is there any way other than a punch to get the hole bigger? I was ready to buy another step bit, but if the metal is burned to the point of where a bit won't cut it, what then? Would a grinder work? Something like a grinding attachment on my Dremel?

You were probably spinning the bit too fast, so you hardened the area around the hole. You can try to break through that with a grinding attachment, just be sure you don't go beyond your hole target size.

IMO, you're going to have an easier time using the drill to make a pilot hole, then using hole punches to get to the final dimension. It's easy to make a 1/2" hole, to feed the shaft for the hole punch through. Then a few (not many once you've taken up the slack) pumps on the hydraulic ram for the hole punch and you're done.

IME, the HF bits are really crappy. Go a little too fast, or don't flood with oil/lube/coolant, and they're pretty much toast. I've had far better results with cobalt bits. Also, you need to go SLOW with the bit speed. If your drill has speed ranges (for hand held) get into the low speed range and go just fast enough to get the bit to turn/cut. I wouldn't go more than 1/2 speed on that setting (<300 rpm). You can go faster on the small holes, but once you get above about 1/2", go SLOW. It also pays to have someone helping with hitting the spot with coolant/lube while you're drilling. Unless you have a system to do that for you.

 

[Cioffi]

You were probably spinning the bit too fast, so you hardened the area around the hole. You can try to break through that with a grinding attachment, just be sure you don't go beyond your hole target size.

IMO, you're going to have an easier time using the drill to make a pilot hole, then using hole punches to get to the final dimension. It's easy to make a 1/2" hole, to feed the shaft for the hole punch through. Then a few (not many once you've taken up the slack) pumps on the hydraulic ram for the hole punch and you're done.

IME, the HF bits are really crappy. Go a little too fast, or don't flood with oil/lube/coolant, and they're pretty much toast. I've had far better results with cobalt bits. Also, you need to go SLOW with the bit speed. If your drill has speed ranges (for hand held) get into the low speed range and go just fast enough to get the bit to turn/cut. I wouldn't go more than 1/2 speed on that setting (<300 rpm). You can go faster on the small holes, but once you get above about 1/2", go SLOW. It also pays to have someone helping with hitting the spot with coolant/lube while you're drilling. Unless you have a system to do that for you.

This is helpful. But just so I'm clear: once the steel is hardened, a bit won't cut, right? Also, your comments suggest that a grinding wheel (something that would fit a Dremel) will take away the steel, which means I could potentially either (1) burr away the hardened metal and try the bit again or (2) grind away the material to get to my hole size.

 

[Golddiggie]

This is helpful. But just so I'm clear: once the steel is hardened, a bit won't cut, right? Also, your comments suggest that a grinding wheel (something that would fit a Dremel) will take away the steel, which means I could potentially either (1) burr away the hardened metal and try the bit again or (2) grind away the material to get to my hole size.

You'll need to use some silicon carbide (or aluminum oxide) burrs to grind away the hardened steel. once you get through the hardened material, you might be able to finish with the bit, again. It's also possible that you've ruined the bit after you hardened what you were going into. Coated HSS bits can only do so much. To really cut easily, you need to use tooling made to cut the material.

I'm not sure how much material you'll need to remove to get past the hardened area. It might be <1/32" or >1/8". If it's the larger amount, then you'll be getting to your target size. Depending on the element, you might have some fudge room to work with.

Working with stainless is where either experience, or having someone with experience to help you out, really comes into play. It's not the same as drilling mild steel, aluminum, or other softer (and non-hardening) materials. You can typically drill through aluminum really fast. Try to do that with stainless (or tool steels) and you'll be destroying bits in a hurry.

I have a floor drill press that I've thought about using to drill the next keg with. It's lowest speed is 300rpm, so it could do a good job. I'm working on making a coolant/lube dispensing system too. I'm actually using some brewing related items in that construction.

 

[kh54s10]

I needed 3 holes in my SS pots. I used the Harbor Freight bit for a 7/8" hole and ended up needing to grind just a tiny fraction to get my fittings through. I used a Dremel. It is amazing how long it takes to grind - probably somewhere around 1/64".

I hoped the bits would last long enough to drill the holes I needed. It did. I just chalked up that cost to the price of the project. I still have it but don't really care how many more holes I might be able to drill. If I need more I will buy another bit.