Enlarging "reaming" sink hole in kitchen basin

Forums › Home Workshop DIY › Enlarging "reaming" sink hole in kitchen basin - seeking conical drill bit

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andrewNZ

2487 posts

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#1586840 5-Jul-2016 22:54

If you can hire/borrow a die grinder, a carbide burr will do ot no worries. You just need to hold it firmly, if they bite and rattle around the hole, they smash the burr teeth.

gzt

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#1586843 5-Jul-2016 23:12

Hatch:
$8.00 + GST hire a day in Christchurch.

http://www.smithshire.co.nz/equipment/plumbing/chassis-punch-38mm.html

Bloody Auckland.

It can pay to call a couple of local branches and ask for that. Not all stock is online.

eracode

Smpl Mnmlst
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#1586855 6-Jul-2016 00:58

Not sure what your budget is, but have you seen this?:

http://wwwb.trademe.co.nz/building-renovation/tools/hand-tools/files-chisels/auction-1117867235.htm

Sometimes I just sit and think. Other times I just sit.

Hatch

797 posts

Ultimate Geek

#1586941 6-Jul-2016 09:35

andrewNZ: Where in the country are you.

If you're in Dunedin I might be able to find a punch the right size and do it for you.

Edit: never mind, Auckland

I ended up calling a plumber today to do the job as the old tap started leaking badly overnight.

My preferred plumber is booked up until Friday so called another plumber working in the Papakura (Auckland) area I found via google.

He said that he did have a chassis punch but because there was an existing hole it would not work. He said he would have to manually enlarge the hole with a hand file.

Not sure if that's correct, but I pushed off the job and my father is going to help me file the hole and install the new tap unit.

I suppose if the hole is only being enlarged by 2mm, it is possible that a chassis punch could slip and end up bending the edge rather than shearing it? I've never used one and can only go off what the plumber said.

Edit: Original hole is 34mm, enlarging to 38mm. So 2mm off across the circumference.

Hatch

797 posts

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#1586945 6-Jul-2016 09:43

jpoc:

The correct tool for this job is a knockout punch. I have had to do exactly this job in the past and that is what I used. Works just fine.

You will get a much better finish to the hole than if you use some form of spinning cutter and there is no risk of overheating anything.

The plumber indicated that a chassis punch would not do the job in my instance. In your case were you only shearing off a couple mm?

Hatch

797 posts

Ultimate Geek

#1586950 6-Jul-2016 09:48

eracode:

Not sure what your budget is, but have you seen this?:

http://wwwb.trademe.co.nz/building-renovation/tools/hand-tools/files-chisels/auction-1117867235.htm

Rather not buy a tool for single use and never have to use it again. Prefer to hire or even just manually do the job.

Bung

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#1586959 6-Jul-2016 09:59

What is the mixer model? Often the specs will have a minimum and maximum hole size. With minimum hole size you may have to take one of the flex hoses out until you've got the other through the hole. Alternatively unless the base has a step locating in a round hole you might get away with just filing the hole oval enough to fish the hoses through.

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Hatch

797 posts

Ultimate Geek

#1586961 6-Jul-2016 10:05

Bung: What is the mixer model? Often the specs will have a minimum and maximum hole size. With minimum hole size you may have to take one of the flex hoses out until you've got the other through the hole. Alternatively unless the base has a step locating in a round hole you might get away with just filing the hole oval enough to fish the hoses through.

Can't find exact model online, but close to this:

https://www.bunnings.co.nz/foreno-icon-coil-sink-mixer-chrome-wels-mains-4star_p00262174

The enlarged hole is to accommodate the "step". Not simply an issue of getting the hoses in, they fit fine already when we tried to install the first time.

MikeAqua

7773 posts

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#1586984 6-Jul-2016 10:31

If you only have 2mm to remove filing is pretty much your option.

You could put a round file in a cordless drill if you want to speed the process up a little

Mike

Bung

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#1587011 6-Jul-2016 11:02

Hatch: The enlarged hole is to accommodate the "step". Not simply an issue of getting the hoses in, they fit fine already when we tried to install the first time.

If it is a Foreno, most of them seem to require a 35mm hole. You might be lucky you didn't jump straight to 38mm.

Hatch

797 posts

Ultimate Geek

#1587054 6-Jul-2016 12:31

Bung:
Hatch: The enlarged hole is to accommodate the "step". Not simply an issue of getting the hoses in, they fit fine already when we tried to install the first time.

If it is a Foreno, most of them seem to require a 35mm hole. You might be lucky you didn't jump straight to 38mm.

That was a link to one that closely matches the one I bought i.e. not the one I bought. The one I have is definitely 38mm. Foreno mixers are only available on special order otherwise I would just go in and swap for a Foreno one.

jpoc

1043 posts

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#1587391 6-Jul-2016 23:39

Hatch:

jpoc:

The correct tool for this job is a knockout punch. I have had to do exactly this job in the past and that is what I used. Works just fine.

You will get a much better finish to the hole than if you use some form of spinning cutter and there is no risk of overheating anything.

The plumber indicated that a chassis punch would not do the job in my instance. In your case were you only shearing off a couple mm?

I was making an existing hole bigger but I do not remember the actual amount of increase. It was not so much though.

But let's imagine that your 2mm increase is problematic. What would I do?

1) Head off to my local metal dealer and buy a small offcut of steel sheet the same thickness as my sink.

2) Drill a hole in part of the offcut and then use a 34mm punch to make a 34mm hole. I would discard the hole and use the middle bit which would in effect be a 34mm dia disk with a hole in the middle.

3) I would put that disk in my shop press and give it a bit of a squeeze in order to make it nice and flat.

4) Take the rest of my little offcut and cut it into two pieces, clamp them together and drill out a hole to suit my chassis punch.

5) Use the 34mm dia disk to fill the existing hole in the sink and put the two offcuts on either side of the disk with the centre holes lined up.

6) Put the 38mm punch onto the work piece and punch a nice 38mm hole in the new composite structure.

7) Admire my nice new 38mm hole in the sink.

You can buy these punches off amazon or aliX for less than the cost of hiring them in NZ.

Adamww

48 posts

Geek

#1587456 7-Jul-2016 08:55

Hatch,

LOL at all the helpful advice here...

Anyhow if you haven't got it sorted by the weekend, I have a engineering workshop in Henderson, It might be a bit of a hike but I would be happy to lend you whatever you need for the job. I suspect a chassis punch wont work well in this case since you are only taking a 2mm bite so I would probably give you a die grinder and carbide burr unless one of my step drills is big enough...

I assume you can email or PM me through this board.

Hatch

797 posts

Ultimate Geek

#1587551 7-Jul-2016 11:35

jpoc:

I was making an existing hole bigger but I do not remember the actual amount of increase. It was not so much though.

But let's imagine that your 2mm increase is problematic. What would I do?

1) Head off to my local metal dealer and buy a small offcut of steel sheet the same thickness as my sink.

2) Drill a hole in part of the offcut and then use a 34mm punch to make a 34mm hole. I would discard the hole and use the middle bit which would in effect be a 34mm dia disk with a hole in the middle.

3) I would put that disk in my shop press and give it a bit of a squeeze in order to make it nice and flat.

4) Take the rest of my little offcut and cut it into two pieces, clamp them together and drill out a hole to suit my chassis punch.

5) Use the 34mm dia disk to fill the existing hole in the sink and put the two offcuts on either side of the disk with the centre holes lined up.

6) Put the 38mm punch onto the work piece and punch a nice 38mm hole in the new composite structure.

7) Admire my nice new 38mm hole in the sink.

You can buy these punches off amazon or aliX for less than the cost of hiring them in NZ.

Wow such a mammoth undertaking worthy of a nice ....um..hole in a sink which will be covered by a tap.

Hatch

797 posts

Ultimate Geek

#1587552 7-Jul-2016 11:38

Adamww:

Hatch,

LOL at all the helpful advice here...

Anyhow if you haven't got it sorted by the weekend, I have a engineering workshop in Henderson, It might be a bit of a hike but I would be happy to lend you whatever you need for the job. I suspect a chassis punch wont work well in this case since you are only taking a 2mm bite so I would probably give you a die grinder and carbide burr unless one of my step drills is big enough...

I assume you can email or PM me through this board.

Hey that's a lovely gesture from you and much appreciated.

In the end we just followed what the plumber had said he would have done. My father came over and did the job whilst I was at work. A hand file and some elbow grease, beauty in simplicity (but perhaps not a very pretty hole lol).

Flicked my dad a $50 for his time and hard work too. Dad's rock!

PS: Thank you for everyone's very helpful and entertaining discourse. At times I forgot I was just making a hole a bit bigger and imagined we were attempting some amazing engineering feat. Much obliged to you all.

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