Drilling a cast iron skillet

So, between yesterday and today I purchased a lot of 8 six-inch cast iron skillets from a garage sale. All are unmarked...most look to be pre-1960 USA made (a couple I know are Lodge and Wagner). Most are pretty rough...I'm not sure they won't be pitted out after I clean them up. To be honest, I didn't even check to see if they were warped or not (I couldn't walk away at two bucks each).

Even if they aren't salvageable for kitchen use, I have a few ideas. One is to clean the rust off, paint them gloss black...then paint pastoral images (barn, farmhouse, old-timey kitchen, etc) on the bottom. The problem with this is that I'm no artist.

The second idea is to clean them up, paint them gloss black and turn them into clocks! As this involves drilling a hole in the center, gluing on a face and mounting the movement and hands, it should be withing my artistic ability. My only question is about drilling the hole.

To mount the movement, the hole will have to be about 5/8 of an inch in diameter. I do not own a drill press (but perhaps a neighbor does) so will likely be drilling the holes by hand. Currently, I'm planning on doing four as Christmas gifts. Do I need a special bit for this? Any tips on how to get this right? I do have a couple broken skillets to practice with, BTW.

Thanks for your help!

If it were me, I'd torch cut them.

So don't have a torch...

Really good carbide drill bit, slowish revolutions, and lots of oil to keep it cool. And patience, lol. But I'm no machinist! So all you handy men and ladies out there: help!

Seems like high speed steel (Google HSS drill bits) will work like a charm. Just oil the bit during the drilling.

DC_MPA said:

Seems like high speed steel (Google HSS drill bits) will work like a charm. Just oil the bit during the drilling.

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See! I just knew there were smarter folks than me still awake!

Lol Dave, I highly doubt I'm smarter than you! Didn't mean to steal your thunder on that post. I didn't see you mention virtually the same thing. Great minds think alike

What are you bottle feeding in your profile pic?

Thanks for the info! Suggestions on what kind of oil to use?

Motor oil, 3-1, just a general lubricant to keep things cool. Doesn't need to be expensive, just something to drip on the drill spot or dip your drill bit in.

I've never drilled a cast iron pan but I was reading up about installing a programmer to my truck. One of the tasks is to drill a hole in the exhaust manifold to install the exhaust gas temperature sensor. The exhaust manifolds are cast iron just like your pans. From all that I've read cast iron is supposed to be a fairly soft metal making it easy to drill through. Just find a good quality metal cutting bit and go slow and steady adding oil to the bit to keep it cool. For a 5/8 inch hole you may want to start out with a smaller bit and work your way up through some larger sized bits in creasing the size of the hole with each larger bit.

As a tradesman that has worked with some cast iron at various times in my career, I can confirm as stated by a few above. Any good quality drill bit should be fine. Keep slow revolutions on your drill and keep it well lubricated. There are cutting oils out there that are specialized for cutting/drilling but most things like a 3 in 1 oil should work fine.

For a 5/8" hole I would recommend starting with something like a 1/4" to start, then a 7/16", followed by your 5/8". You can do 1/4 to 5/8, but it will take more pressure to make the heavier cut, thus more heat which reduces your cutting effectiveness, degrades your tooling, and work hardens your material making it more difficult to do especially by hand.

Also, if you are going to paint it, remember that cast iron is porous, so your cutting fluid will soak into it. That in mind, you may want to look for a clearer type of fluid instead of using something like motor oil. Better yet a water soluble one like true tap.

Also make sure you fasten the pan well so it doesn't spin around and let you know you messed up if the drill bit catches. (Don't ask me how I know that......) And be gentle when the drill is ready to break through the other side. This is when it is most likely to catch on you and cast iron can break.

(And a torch doesn't work well on cast iron.)

If you get good at drilling holes, you can try this. This was taken from a 1959 Popular Mechanics magazine.

skijor said:

"Cast iron drills readily but being non ductile and infused with graphite the chips are crumbly. Drill as you would for mild steel but without coolant."
http://www.practicalmachinist.com/vb/general/drilling-cast-iron-232319/index2.html#post1650889

I've only done a bit of turning of cast iron. Yes, it makes a crumbly mess, but cuts easily with the right tool.

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I stand corrected on the coolant and learned something. Listen to the machinist instead of the old field grunt.

New drill bit on a battery powered drill and it will cut like butter. Cast iron is soft but brittle, that's why a sharp bit at a low speed is king. I think you're overthinking this!!! It won't be hard at all buddy (no pun intended). Good luck, you have some great ideas

Thanks for all the help guys!

A cast iron pan clock is a cool idea!
@skypsyd

Thanks! Hopefully we'll see how it pans out in a few weeks...

I would use a carbide tipped holesaw. less actual cutting surface, cleaner hole.

Hair apparent said:

I would use a carbide tipped holesaw. less actual cutting surface, cleaner hole.

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Can you get holesaws that small. I have drilled cast iron a couple of times and no problems. Just use a good carbon steel or high speed steel bit, and it will go through like a knife in hot butter. As far a clean hole, a good bit will leave a totally clean hole.