Keggle, Step Bit, and Burned Metal

[Cioffi]

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 (WD-40). So, 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 will a new bit cut? Would a grinder work? Something like a grinding attachment on my Dremel?

 

[Bensiff]

Somebody with more experience can help better than I can...that said, my understanding is that stainless will get work hardened so if you really heated it up trying to cut, it might have gotten too hard to continue with the step bit. As a side note, I would consider using an actual cutting fluid in the future, WD40 is a water displacing lubricant and penetrating oil that was designed for corrosion resistance, not cutting metal.

 

[MidTNJasonF]

I have drilled about three dozen holes in close to two dozen different kegs on the same pair of Harbor Freight uni-bit/step bit drills. I use a foaming cutting oil for stainless steel (also from Harbor Freight). Slow drill RPM with heavy downward pressure on the drill. If your chips from the bit are still silver or slightly blue and the edge of the hole is still shiny sliver you are fine. If you start seeing straw colored, brown to deep blue/black colored, or golden colored metal you have over heated the metal and work hardened it.

It will be very difficult to drill further at that point if it is work hardened. Stainless gets very tough. You can get through it but if you already spent some time trying with your current bit it may be toast. A fresh bit, cutting oil, and proper technique will get you the rest of the way but it may kill the new bit as well for that step size.

 

[Daddo07]

I drilled my first using WD40 and smoked it. Using cutting oil for the rest made an enormous difference. You may also need a new bit as the HF stuff isn't the highest quality steel and will dull very quickly if it gets too hot.

 

[Dawai]

Hi.

THAT sounds like a electrical knock out size. Greenlee electrical punch knock out. It does distort a bit around a curved object to pull a knock out thou.

2,(he's right) on the drilling "too fast" for the cutting edge. You can take a normal drill, push like heck and just bump the drill motor over slow, on, off, on (repeat) and it will throw a curl, stainless does not seem to be that hard, just clogs up the cutting edge and then work-hardens, tempers the metal, if you ever start throwing blue chips, curls, you are pretty much done.

KNow anyone with a plasma cutter? you cut a template with wood, clamp it to it, and just ring around the circle.. It's plasma cutter tip radius, minus cutting "width" for a offset (hole that much larger with cutting inside line) or "plus" radius if cutting outside a pattern. I do this all the time, cutting stainless sheet, I lay down a ruler and have a cut in ten seconds that looks like a saw. I have jigs for push buttons, meters, and did have them for industrial AB monitors.

I did the STC1000 meter plate from mirror stainless in about thirty seconds using a ruler to cut the penciled trace of the unit. Drilling the end mount holes took longer to chuck up the right bit in the drill press.

 

[Stealthcruiser]

Drilling rules to live by:"Slow speed, heavy feed"...........And yes, you need a cutting tool lubricant, and a new bit..............It'll go, it ain't ruined yet!

 

[Monster Mash]

I've cut over 10 holes with my HF step bit and just used water to keep it cool. As I'm cutting I run water over it and it never gets a chance to get hot, when you use WD-40 the oil and the stainless gets hot which hardens the metal and dulls the bit.

 

[Cioffi]

I have drilled about three dozen holes in close to two dozen different kegs on the same pair of Harbor Freight uni-bit/step bit drills. I use a foaming cutting oil for stainless steel (also from Harbor Freight). Slow drill RPM with heavy downward pressure on the drill. If your chips from the bit are still silver or slightly blue and the edge of the hole is still shiny sliver you are fine. If you start seeing straw colored, brown to deep blue/black colored, or golden colored metal you have over heated the metal and work hardened it.

It will be very difficult to drill further at that point if it is work hardened. Stainless gets very tough. You can get through it but if you already spent some time trying with your current bit it may be toast. A fresh bit, cutting oil, and proper technique will get you the rest of the way but it may kill the new bit as well for that step size.

Okay, all these comments are helpful. I'll go with "a fresh bit, cutting oil, and proper technique" and give it another go. I may try and grind some of the hardened steel away and see if some "fresh" steel may help things along. I'm just over an inch with the hole, but need 1 1/4" - almost there!

Also, I don't doubt a knock-out punch would work well, but I didn't want to pay the price for a Greenlee. Of course, after several bits, the price is climbing.

 

[processhead]

In my experience, knock-out punches do a poor job in existing holes that are already close to the finished hole size.
You will often get a ragged hole under these conditions.

 

[Bensiff]

Good ol' HF bits, great for one off projects where you don't mind dealing with some extra clean up work once the hole is punched. But, I got to say, spending money on good bits if you are doing a lot of work is well worth it as they leave a much cleaner hole.

 

[Cioffi]

Okay, got a 1.25" punch from work. Finished up the existing 1" hole and put a new 1.25" hole in another keg. All is well! Thanks everybody for the help.

 

[nickw85]

I have drilled about three dozen holes in close to two dozen different kegs on the same pair of Harbor Freight uni-bit/step bit drills. I use a foaming cutting oil for stainless steel (also from Harbor Freight). Slow drill RPM with heavy downward pressure on the drill. If your chips from the bit are still silver or slightly blue and the edge of the hole is still shiny sliver you are fine. If you start seeing straw colored, brown to deep blue/black colored, or golden colored metal you have over heated the metal and work hardened it.

It will be very difficult to drill further at that point if it is work hardened. Stainless gets very tough. You can get through it but if you already spent some time trying with your current bit it may be toast. A fresh bit, cutting oil, and proper technique will get you the rest of the way but it may kill the new bit as well for that step size.

Mid is right on. Spoken like a machinist. I think this is the best reply I have seen to this frequently asked question. The big thing is going slow and people don't realize how slow. variable speed drills get you in trouble because you just pull the trigger and off you go. Your speed should seem almost too slow to the untrained drilling Jedi who usually just takes the drill full speed and plows it into a piece of wood.

 

[MidTNJasonF]

Mid is right on. Spoken like a machinist.

That is because I am a former machinist

Well I guess I am still a machinist but now I am a Quality Assurance Manager. Now I tell other Machinist how much they screwed up and tell Machine Shop owners how to pass an ISO audit.