Wordwork question

[Andrew Gabriel]

Been asked to fit a basin for a friend. The basin is going into a 40mm thick oak worktop. He got the carpender fitting the worktop to cut the hole for the basin. The tap and separate spout each need holes drilling. The thread on the base of the spout which takes the locking nut isn't long enough to go through the 40mm worktop, so I need to create a stepped hole. That would be fine, except there's too little clearance under the worktop to get a drill or possibly even a bit in. So, I'm looking for any ideas.

Only thing I've thought of so far would be to get a right angled drill, and to use a really short bit -- perhaps a cupboard door hinge cutter if they come big enough (haven't checked yet -- need about 40mm dia).

The other thought was to use an auger bit (if I could find a short enough one) in something like a ratchet spanner instead of a brace and bit, but I've never seen a ratchet spanner which can take a bit.

My plea not to fit the worktop until I had done the plumbing fell on deaf ears. Well, I have some sympathy -- he finds it almost impossible to get good carpenders to come round, and having managed to get one for a day, he wanted the guy to do as much as possible whilst he was there. It's now all tiled and grouted in, so I can't remove the worktop without doing a lot of collateral damage.

[nightjar]

Is there enough clearance to put a threaded socket over the tap thread? That would allow you to screw a length of pipe in under the tap and to put the tap connector on the end of that.

Colin Bignell

[stuart noble]

Shame you can't find a way to extend the thread but I guess, even if such a fitting was available, it would involve making the hole bigger.

IME the only way to make a big hole slightly bigger is to fill the original with dowel or something to give you a centre. Otherwise, whatever you use is going to bounce around mercilessly.

I suppose one good thing is it won't have to loook pretty from underneath. A flexible drive shaft to drill a series of small holes round the edge? A Dremel attack possibly? Isn't this what a reamer does in metal work? Sorry, just rambling now but it might trigger somebody into suggesting a proper solution.

Do tell us how you get round the problem

[Cicero]

================================== Many augur bits have a hexagon stem which will fit well into a standard hexagon socket spanner (8mm for mine) which in turn will fit your ratchet. I have some stubby augur bits (about 4" long) bought some years ago from Screwfix but there's no brand name and the largest I have is about 25mm so you might have to go to a specialist tool shop for the large size you need.

A possible alternative is a 'joist brace' but they're difficult to find and expensive:

you can't get suitable tools to do the job you might consider cutting out for a solid brass plate (about 6mm thick) which could be countersunk into the worktop and which would be stronger than individual countersunk holes.

Cic.

[Andrew Gabriel]

There is no hole for the spout yet, so I could certainly make an oversized hole -- there's quite a large flange to clamp against the worktop surface. The spout takes a 3/4" tap connector. Is that the same as a 3/4" BSP parallel thread? There is _just_ enough thread sticking through to get the tap connector on. Maybe I could cobble something together using a 3/4" female connector of some type (thumbing through BES catalogue...)

[The Natural Philosopher]

I have to say I solved this one by screwing flexible connectors on my taps, and drilling a hole big enough for the lot, and setting the whole shebang on a load of car body filler.

I hope the taps outlast the worktop..

A POSSIBLE way to do this has occurred to me.

If there is room at the top for a drill, get a router bit and insert the shank upwards into the tap hole and do a bloody rough counterbore useing the wrong edge of the tool,

Likewise you may be able to reverse a hole saw somehow and achieve the same.

[stuart noble]

It certainly gets one out of some tight corners that stuff.

[George]

What would be ideal is a sheet metal punch with a long 50mm shaft? If it was designed for metal it'll cut through wood without knackering its cutter. ;-)

[Lobster]

Presumably you haven't got enough space for a bit on the end of a flexible drive shaft?:

Alternatively - and this is definitely me thinking aloud, but would there be some way of forming a stepped hole from above; eg some type of (customised?) bit with a cutting edge on the top edge rather than the bottom (or an inverted holesaw?), which could be inserted from below and fitted to the drill above the worktop?

Tricky one!

David

[Peter Scott]

Presumably it doesn't matter if the recess is too large. Is there much space around to allow a bad aim to be invisible? Could you try using a woodworking chisel and a steel hammer? You'll probably scrape off some skin on your knuckles but perhaps used with the angled side upwards you might be able to chisel away a suitable depth. One of the squarish chisels would be best rather than a flat one. What are they called? Mortice chisel?

_____________ ___ !_____________Wood \ \ \ \ \ \ \ \Chisel

The angles aren't right but you get the idea?

Peter Scott

[Andrew Gabriel]

That gives me an idea. If I can find a router bit with a wide cutter on narrow shaft, I could use that to ream out the bottom of the hole. I have a cheap router and a collection of bits, but none fitting that description.

[nightjar]

Yes.

It is possible to get reduced OD female connectors in stainless steel, but I have to buy them 50 or 100 at a time. I would offer you a couple, but I'm fairly sure I'm out of 3/4". It is a bit small for most of my customers.

Colin Bignell

[The Medway Handyman]

What about one of those router cutters used to make biscuit joints?

[Pete C]

Hi,

If there's good access from above, I'd use two holesaws on a length of studding, one the size of the existing hole facing down, and a bigger one at the end facing up ie the wrong way round. The drill would be above the worktop.

The first one would help centre the second larger one, and then pulling on the drill will make the second one drill into the bottom of the worktop.

I'd also grind a couple of flats on the studding to suit those in the holesaws.

cheers, Pete.

[John Rumm]

Is the basin fixed or can it be removed?

How close to the edge of the basin hole does the tap hole need to be?

If its less than say 80mm I would make a plunge cut into the side of the worktop from the basin opening using the multimaster. One parallel to the worktop at say 25mm down from the top, and two further ones vertically to join the lower edge of the worktop to the ends of the first cut. One final partial cut form the underside to take out a segment from the underside of the worktop. Now just drill clearance holes from the top for the taps over the newly thinned section.

Drill tap hole | | | v

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[Paul Matthews]

Could you possibly get in with a right angle drill and a router bit? Something like

maybe a plug in the hole to control depth?