enlarging cut-out for downlights....

[ffoxy99]

Got a bit of a problem..... (waffle/background is in yellow and can be skipped)

I fitted one of those plastic suspended ceilings to a lady's kitchen about 7 years ago.

I put 4 Diall downlights in, from B&Q, which don't have replaceable bulbs.

2 have now expired.

The lady asked me to change the bulbs but obviously I need to change the full unit(s).

There are about 18 pages of them on Toolstation & Screwfix and shelves full of them in B&Q but it's not immediately clear what size cut-out you need for them.

I found some this evening in B&Q which looked like what I needed. The leaflet (box had already been opened) said cut-out 72mm to 76mm.

I went back to the customer's home and measured the existing cut-outs. About 67mm.

If you can't find new units that suit the existing hole what do you do?

Once a hole is already there you can't use a holesaw to enlarge it as there's nothing for the pilot-drill to centre on.

Short of trying to make the hole bigger by laboriously cutting the plastic with a Stanley are there any hacks for this? It must be quite a common problem.

Or can the bulbs in these actually be replaced?


bulb can't be replaced

[moderator2]

Yellow removed as it was impossible to read.

[wine~o]

Simplest answer is to cut a square of ply,, screw over the hole and cut a new hole through the ply and the plasterboard. Never use a fitting that doesn't have replaceable bulbs.

Bit of filler on the screw holes after.

[Neelix]

What you need is an arbour , a 67mm cutter and a 74 mm cutter.

Put the 74 on the arbour, then the 67 and then , very carefully, put the 67 into the existing hole and gently drill out to 74mm.

Btw, KSR gu10 downlights are pretty much the best (ksrfrd400) and you can choose between different finishes of bezels including IP68 for bathrooms

[ffoxy99]

Yellow removed as it was impossible to read.

Thanks for checking with me first of all. I explained why it was in yellow

[ffoxy99]

What you need is an arbour , a 67mm cutter and a 74 mm cutter.

Put the 74 on the arbour, then the 67 and then , very carefully, put the 67 into the existing hole and gently drill out to 74mm.

Good call. Will need to look out that original holesaw

[OnlyMe]

I've never had a problem just using a bigger hole cutter and using the edge of the existing hole to guide the cutter (it then cuts out a moon crescent shape). Or use a pad saw. If loaded buy an oops arbour

[ffoxy99]

FWIW I got the job done OK. Turns out the measurements for the lights don't seem to be that accurate. Possibly the figure they give is just what they think the best-sized holesaw should be.

The new units were only a fraction wider then the old so I just trimmed a little off the plastic ceiling to get the new ones in