Something like this perhaps.
https://www.ebay.co.uk/itm/301573686...kaAokmEALw_wcB
Hi
Fitting some downlights and the old ones have a smaller diameter than the new ones to using the hole saw in the drill is proving challenging.
I’ve seen some step drill bits that would be ideal for this type of work - but the max size I can find is 65mm and I need a 75mm hole.
Or, if anyone has any suggestions about a good way to do this - that doesn’t rely on being able to get above the light - then would be good.
Current plan is to cut a piece of wood 65mm and use that in conjunction with the 75mm hole saw to hopefully get it to bite and not skid off the ceiling.
Cheers
Something like this perhaps.
https://www.ebay.co.uk/itm/301573686...kaAokmEALw_wcB
Started out with nothing. Still have most of it left.
Or this.
Started out with nothing. Still have most of it left.
Padsaw's the easiest less faffing about method
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This is what you need;
STARRETT A19 HOLE ENLARGEMENT ARBOR
Yep, you want a Starrett A19:
https://www.screwfix.com/p/starrett-...r-58-6mm/386rf
https://www.youtube.com/watch?v=QEARtTlWrVI
You mount the smaller holesaw on to it & it replaces the pilot drill. While you're at it these work brilliantly:
https://www.amazon.co.uk/DADE-Collec.../dp/B08GKWGK8W
The DADE is a great piece of kit, I first saw (!) it when an electrician installed our dowlighters whilst using one - and what a big difference it made.
R
Ignorance breeds Fear. Fear breeds Hatred. Hatred breeds Ignorance. Break the chain.
I just used a mini hacksaw blade to enlarge the holes when I had to do similar when changing out the downlighter in the kitchen.
An alternative and possibly better method, that can make the new hole off-centre:
If hand holding seems sketchy, I'd use super glue and masking tape rather than nailing the template in place:
If it's just a couple of holes, then a pad saw would do: https://www.screwfix.com/p/forge-ste...3-160mm-/210ky
Well this is a pain in the backside - bought one of those Starrett arbor enlarger things and the damn thing doesn’t fit my holesaws or the existing arbors.
I have at least 3 different sets that all work together but this seems to be specific to a Starret arbor.
The threaded part doesn’t fit through the holesaw opening and the shank doesn’t fit into the pilot drill opening.
Think I’ll return it and go back to the original idea of using a wooden blank.
Last edited by bambam; 1st June 2023 at 21:24.
I drew a circle to show where I needed to cut to enlarge the hole, then cut at 90 degrees to the drawn line at various places then used a mini hacksaw blade to cut between the cuts made earlier.
I did have a hole saw but like the OP found that it couldn’t really be used to enlarge as it would just judder and wander. A pad saw would have better but I don’t own one.
As you only need to pilot the hole my approach would be to -
1st option (assuming enough overlap)
Cut a batten with a hole drilled in it (to take the hole saw pilot). Put the batten into the ceiling and centre the hole in the middle, mark the batten.
Fix the batten with screws or pins through the plasterboard (or even tape ?) start the hole until you have a bit of a groove to guide it. Remove batten and use the groove to guide the hole saw to cut the groove out.
If there isn't sufficient overlap (I would have thought with bezel there would be) I would be tempted to do the same and fill the holes. If going this route I would try one screw and a large pilot hole to minimise filling as I would think could hold in place sufficiently like that.