How do I drill a small hole in an enamel-covered cast iron pot lid?

September 30, 2009 7:56 AM

How do I drill a small hole in an enamel-covered cast iron pot lid? I'd prefer not to chip the enamel, but it would be acceptable if I do. I need a 1/8-inch hole. What type of drill bit do you recommend?
posted by judytaos to Home & Garden (20 answers total)

You might have already thought of this, but just in case you haven't - I'm assuming you're talking about a Le Creusant or Martha Stewart style enamel covered cast iron pot. Well, almost all of them have similar plastic lid tops which can be unscrewed from the bottom and removed, leaving a small hole in its place. Would that work?
posted by banannafish at 8:00 AM on September 30, 2009

You need a tile bit. At least to get through the enamel. They have abrasive at the end instead of a sharp point.
posted by notsnot at 8:01 AM on September 30, 2009

Response by poster: Well, almost all of them have similar plastic lid tops which can be unscrewed from the bottom and removed, leaving a small hole in its place.

Thanks, banannafish. Yes, it's a Le Creusant and does have a screw-on knob, but I'd like to leave it in place and add a hole off-center.
posted by judytaos at 8:06 AM on September 30, 2009

Tile bits are good, or you can try a ceramic bit. I've had good luck with abrasive conical ceramic bits for my Dremel tool on a fast speed with minimal pressure. I do a shallow pre-drill with the conical bit so that it just breaks the surface on the opposite side. Then switch to a straight metal bit to finish boring out the full 1/8" diameter. This should minimize chipping on the top surface, but may still chip a bit on the under side of the lid as you break through while widening.
posted by alight at 8:08 AM on September 30, 2009

A little squirt of oil on the metal where you're drilling can make it much easier- it floats the filings away while you're going.
posted by jenkinsEar at 8:18 AM on September 30, 2009

A diamond burr can be used on a dremel to grind away a small patch of enamel but you might have to do that on both sides and drill the hole through the cast iron with a more normal bit.
posted by bdc34 at 8:19 AM on September 30, 2009

Getting the ground-off spots to match up before you drill could be an issue. I'd use outside calipers to mark the correct spots before drilling. And then I'd probably still chip the enamel.
posted by le morte de bea arthur at 8:25 AM on September 30, 2009

Cast iron is a huge pain in the ass to cut or drill. Use a carbide or cobalt drill, go really slow and keep the area you're drilling well oiled to dissipate heat. I've cut cast iron pipe before, and the only way I was able to do it was by using an abrasive saw blade.

I'd recommend not doing it, if that's a possibility.
posted by electroboy at 8:26 AM on September 30, 2009 [1 favorite]

To drill through the iron you'll need to "start" the hole by using a center punch so the drill bit doesn't wander or skitter off. That will probably chip the enamel.

If you use a tile bit or a ceramic bit to get through the enamel it might be enough to center the reg'lar old drill bit you'll need to drill through the iron.
posted by Max Power at 8:27 AM on September 30, 2009

I think the best way to avoid chipping the enamel is to go slow, use some cutting oil (or WD-40 if you're desperate), and drill a pilot hole first. If you can use a drill press or some sort of guide that would be ideal, since you'll avoid wobbling the drill back and forth and possibly contacting the enamel with the side of the drill bit.
posted by backseatpilot at 8:27 AM on September 30, 2009

Electroboy is correct in my experience: carbide bit, go slow, use lots of oil. If possible, use a drill press with the workpiece securely fastened.

Keep in mind that the enamel will be weakened around the hole and will inevitably chip around it with use.
posted by bonehead at 8:32 AM on September 30, 2009

Best answer: You could maybe also drill through the plastic handle, leaving you a handle (and handy steam vent to burn yourself on)
posted by CharlesV42 at 8:36 AM on September 30, 2009

It may be possible to buy hollow screws to replace the handle screw. Check your full service hardware store.
posted by Midnight Skulker at 8:43 AM on September 30, 2009

Beware of rust. You may want to apply some kind of paint to the edges of the newly created hole.
posted by gregr at 9:02 AM on September 30, 2009

What's the hole for?
posted by electroboy at 9:27 AM on September 30, 2009

Response by poster: What's the hole for?

I'm running some rice-cooking tests, and I want to monitor the temperature of the rice without removing the lid. I'll cook with a Taylor thermometer inserted into the rice through the hole.
posted by judytaos at 10:00 AM on September 30, 2009

Best answer: The Polder digital thermometers have a relatively flat wire attached to the thermocouple. You could probably use one of those, rather than risking permanent damage to a pretty expensive pot.

I've used a couple layers of aluminum foil under a heavy pot lid to get a better seal. Otherwise I'd go with removing the handle and inserting the thermometer through there. The difficulty there would be insulating the thermometer from the lid.
posted by electroboy at 10:17 AM on September 30, 2009

Why don't you just drop one of these in under the lid? I would not want to ruin a lovely enameled pan like yours by drilling a hole in it.

If you do drill, you should season any metal that gets exposed.
posted by Aizkolari at 10:18 AM on September 30, 2009

_{Great minds, electroboy}
posted by Aizkolari at 10:18 AM on September 30, 2009

Are your rice experiments dependent on using the cast iron lid? Could you substitute an inexpensive aluminum lid instead?
posted by zepheria at 10:11 PM on September 30, 2009