Drilling porcelain cast iron kitchen sink

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Mr_David

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I need to drill a porcelain cast iron sink to add an ISE Hot water dispenser.
I found a Relton drill designed just for this.

relton/porc-cut.

Has any one had success with any other products.
I've drilled sinks before but it has been many yrs ago.

I heard that some have tried using a diamond tipped hole saw?
Just looking for options. Thanks
 
Looks a bit pricey but considering the cost of replacing a damaged new porcelain cast iron sink, it seems well worth it IMHO!
 
I did mine with a metal hole saw bit. It took a long time and ruined the bit but it made a pretty nice hole. I went from the bottom up. It did leave some rough edges in the porcelin but they were covered by the hot water faucet. I still don't know if I would want to try it this way in a customers home tho. I now have a set of diamond blade hole saw bits but haven't tried them.
 
After doing an online search on the subject, some have used a diamond coated hole saw to get through the porcelain but getting throgh the cast iron with same bit.... ?

I've cut through cast iron soil pipe with a sawsall but that a very slow process and work.
 
The diamond bit would probably not do so well on the cast iron. You can always grab an old sink and practice.
 
"Hello MrDavid",

I have Drilled MANY Cast Iron Soil Stacks to Fit `Saddle Type` Boss Fittings which then accept Waste Water Pipes [using Male Iron to Copper Connectors],
the Content of the Cast Iron in these Stacks would NOT have been particularly `Pure` - they would have had Many Impurities - BUT I used the `Top Quality` High Speed Steel Holesaws [NOT Used at High Speed for Cast Iron] - which WILL Cut a Good Clean Hole with NO Problems whatsoever - Use a Oil for Cutting Lubrication / Cooling.

On a couple of occasions I have also Drilled Cast Iron Baths - when it would have meant either I Drilled them OR have to Ship them to a Workshop 50 Miles away to be Drilled `Professionally`.

I have Drilled ONE Cast Iron Sink some Years ago - As with the Baths - Once through the Vitreous Enamel - The Cast Iron was No Problem at all.

You obviously would have to Cut through the `Porcelain`[Vitreous Enamel] Surface First - Using a Diamond Tipped Holesaw [As used for Porcelain Tiles] and it would be Good to have a Clean Pilot Hole with which to use for the Cutting of the Surface AND the Cast Iron Cutting - I would ensure that I had a Sturdy Wood Block under the Hole Area of the Sink - hopefully `Securing` it to the Sink in some way - To Drill the Pilot Hole `Into` when through the `Porcelain` and Cast Iron.

Because the Sink should be made of `Good Quality` Cast Iron - You should be at much less `Risk` of causing Damage / Ruining the Holesaw than with the `Impure` Cast Iron of the Soil Stacks that I have drilled throughout My [Earlier] Plumbing Career.

The Cutting In of these Holes to attach the `Saddle Type` Boss Fitting on MOST of the Cast Iron Soil Stacks was because Cutting Out a Section of the Soil Stacks was NOT an Option - Usually the Stack was in an Apartment Block where ANY Disconnection of a Section of the Stack was just NOT Feasible because of the other Occupiers use of W.C`s / Baths / Showers and Kitchens - ANY `Damage` to the Stacks when Drilling would have been a `Disaster` !

I mention those details to show that Drilling Cast Iron - In those cases with plenty of `Impurities` - IS a task that can be undertaken with just `Top Quality` High Speed Steel Holesaws [NOT Used at High Speed on Cast Iron] plus Cutting Oil - And it should be `Easier` / At less Risk with a Higher Quality Cast Iron - such as used in Cast Iron Sinks.

I hope that this Helps a little in giving You the confidence to carry out the Drilling of your Sink.

Regards,


Chris
 
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"Hello MrDavid",

I wondered if My Message was Helpful in any way - Although I did not state anything that You do not already know - I thought that My experiences MIGHT have given You extra confidence that Drilling the Cast Iron Sink would not be a Task that you should be `Worried about` - ?

Perhaps I Wrote Too Much Detail - Again - ??


Regards,

Chris
 
Last edited:
"Hello MrDavid",

I wondered if My Message was Helpful in any way - Although I did not state anything that You do not already know - I thought that My experiences MIGHT have given You extra confidence that Drilling the Cast Iron Sink would not be a Task that you should be `Worried about` - ?

Perhaps I Wrote Too Much Detail - Again - ??


Regards,

Chris

Sorry for not responding. I have not spent much time here on PF Lately.
Occasionally I'd pop in briefly and then depart without making any comments.

Yes Chrism your message was helpful. I have drilled cast iron sinks before but at that time I did have a set of bits designed just for that.

Chris, I did think about looking for an old sink to do a test run on.

I'm just try to avoid having to replace his sink. One reason is lately the finished quality of cast iron sinks have been very poor. Kohler in particular.
We put a sink in a few months ago and it had visible ripples in it. We looked at several others at several different suppliers and they were all just as bad.

Customer is willing to buy the $150 bit to complete a $200 job of even replace his sink if I do chip it, but we're trying to avoid the unnecessary cost.

Thanks for your help

David

I'll be sure to let you know the out come
 
I've been told that if you sandwich the sink between two blocks of hard wood, clamped real tight, you lessen the chances of any wobbling and the hole comes out cleaner. Keep in mind, I have only read this idea and have not tested it personally, so take it for what it's worth.
 
"Hello MrDavid",

Thanks for Your Reply - It is obviously not a good thing that You have found Cast Iron Sinks lately to be of a Poor Quality - I am surprised about this, hopefully there will be NO Impurities where You will be Drilling.

When I was Drilling the Cast Iron Soil Stacks - AND the Cast Iron Baths & Cast Iron Sink that I mentioned I was using `Normal` Best Quality High Speed Steel Holesaws [NOT on High Speed for Cast Iron] - For a Tap [Faucet] Hole probably available in the U.S. for no more than $30 [?] - [Depending on Size] - I used to use Holesaws / Hole Cutters manufactured by a Company called `Starret` - I take it that the $150 Bit that You mentioned is the Diamond Tipped Ceramic / Porcelain Hole Cutter ?? - `Reassuringly Expensive` !

When I Drilled the Baths and the One Cast Iron Sink [Years ago] I used a Glass Hole Cutter and a Porcelain Tile Hole Cutter - Then Drilled the Cast Iron with the High Speed Steel Holesaw [NOT on High Speed].

Although the Ceramic Tile Hole Cutters & Glass Hole Cutters were more expensive than the High Speed Steel Holesaws - NOT 5 Times the Price.

I cannot recommend that You use those `Ordinary` Tile Hole Cutters / Glass Hole Cutters in case of an Accident / Damage - BUT apart from the `Professional` Bath Hole Cutting Process those were ALL that was `Readily Available` to even attempt cutting through the Vitreous Enamel Surface `In those Days`.

I would have Drilled through the `Top Surface` with the Glass Hole Cutter - Just breaking the Surface - Then changed to the Ceramic Tile Hole Cutter to Drill to the Cast Iron Surface - Then the High Speed Steel Holesaw [NOT on High Speed for Cast Iron] to Drill / Cut through the Cast Iron - These should be ALL the Same Size - I would have more than one of the High Speed Steel Holesaws [Just in case] - You must use a Light Oil as a Lubricant / Coolant for the Hole Cutters.

I would advise an Electrically Powered Drill - NOT a Cordless Drill - Drilling WILL drain Batteries Quickly - Even Good Quality Batteries.


I wonder what is the Price in the U.S. for the `PORSADRIL` Kit ?? [On the website that Link is to]

I found this webpage online:

How to drill a hole into a steel cast iron bath with PORSADRILL -


Although I know that You are fully aware of the Drilling Process I wondered if reading the Details about Drilling a Cast Iron Bath and what was used might be a little Helpful [?].


"Good Luck with Drilling the Cast Iron Sink".


Regards,


Chris
 
Last edited:
"Hello MrDavid",


"Good Luck with Drilling the Cast Iron Sink".


Regards,


Chris

Thanks.
The customer opted to just replace the intire sink. I was going to drag the old one home and drill a couple holes in it just see what would of happened.
Not!!! I'm getting lazy and drilling holes at home is probably not gonna happen.:)
 
Thanks.
The customer opted to just replace the intire sink. I was going to drag the old one home and drill a couple holes in it just see what would of happened.
Not!!! I'm getting lazy and drilling holes at home is probably not gonna happen.:)

You mean there's a condition besides being lazy?
 
i love drilling into cast iron sink, its easy money, i have a special porcelain cutter kit, see pic, first you use the drill bit, 2) use bit with the springs to cut around the porcelain,, the the final finish hole saw.... these steps WILL NOT damage the sink.. takes about 15 mins

plumbing 001.jpg

plumbing 002.jpg
 
sorry about the late post, i just came across it today and thought if someone else needed this info here it is... Good Luck
 

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