large Hole saw

[printcom]

I need to make around 40 285mm holes in 12.5mm plasterboard for some lights. I cant seem to find a hole saw that size that doesn't make me wince. Any suggestions?

 

[brightspark]

a keyhole saw get weaving or cuttinghttps://www.screwfix.com/p/irwin-jabsaw-6-165mm-/9535X?tc=RB4&ds_kid=92700022885063853&ds_rl=1241687&ds_rl=1245250&ds_rl=1244066&ds_rl=1248184&ds_rl=1245250&ds_rl=1247848&gclid=EAIaIQobChMI3eCa8pHM5AIVRLTtCh3HYQvuEAQYAyABEgKfBfD_BwE&gclsrc=aw.ds

 

[printcom]

a keyhole saw get weaving or cutting

Thanks but I was hoping for a hole saw type solution as those things and loft insulation don't mix very well

 

[Martinb]

https://www.googleadservices.com/pa...hUKEwjTlISokczkAhUxVRUIHcXaBY4Q9aACCEI&adurl=

Says 29cm may just be large enough.

 

[brightspark]

Thanks but I was hoping for a hole saw type solution as those things and loft insulation don't mix very well

even the trepanning cutters don't go up to that size you could make your own cutter out of an old bandsaw blade cut and brazed together and a bit of flat bar across welded on with a bit iof 10mm round bar welded on but will it be worth it

 

[Ali]

The largest hole saw I’ve seen is 200mm...

What about one of these?

https://rover.ebay.com/rover/0/0/0?mpre=https://www.ebay.co.uk/ulk/itm/323528559951

 

[eLuSiVeMiTe]

https://www.googleadservices.com/pa...hUKEwjTlISokczkAhUxVRUIHcXaBY4Q9aACCEI&adurl=

Says 29cm may just be large enough.

Mines bigger than yours.

https://www.toolstation.com/adjusta...F92f-ehUCg6yYsazgqC-bhanW-8g4DcsaAi6zEALw_wcB

Trepan was my first thought too.

 

[printcom]

https://www.googleadservices.com/pa...hUKEwjTlISokczkAhUxVRUIHcXaBY4Q9aACCEI&adurl=

Says 29cm may just be large enough.

Well spotted, I am going to screwfix tomorrow I will pick one up, thanks.

 

[brightspark]

stand corrected trepanning tools do go that big but it will be still messy using it on a ceiling I use a plastic chinamans hat with cutters on the celling to collect the dust

 

[Spark plug]

Mines bigger than yours.

https://www.toolstation.com/adjusta...F92f-ehUCg6yYsazgqC-bhanW-8g4DcsaAi6zEALw_wcB

Trepan was my first thought too.

It says Silverline so might require 1 per hole

 

[brightspark]

It says Silverline so might require 1 per hole

nearly spilt me beer there laughing

 

[8ob]

stand corrected trepanning tools do go that big but it will be still messy using it on a ceiling I use a plastic chinamans hat with cutters on the celling to collect the dust

All in one https://www.screwfix.com/p/erbauer-...MIq6G3jZXM5AIVi7HtCh0Viws5EAQYAyABEgJ6W_D_BwE

 

[eLuSiVeMiTe]

It says Silverline so might require 1 per hole

It might. Alternatively it might drill all 40 and get you out of the crud another day.

Can never tell with cheap tools.

 

[brightspark]

All in one https://www.screwfix.com/p/erbauer-...MIq6G3jZXM5AIVi7HtCh0Viws5EAQYAyABEgJ6W_D_BwE

I bought one of those from autojumble 20 quid. haven't even bothered to use it. not found the need as I only use up to 150mm and have loads of cutters the right size . only bought it as it was cheap

 

[Barlidge]

I used to cut lots of 295mm holes in ceilings for speaker systems, pad saw def the way to go and loft insulation never caused a problem, the insulation can soon get wrapped up in the pilot drill though.

 

[slim_boy_fat]

only bought it as it was cheap

A common affliction

 

[Shedendman]

You dont say if the plasterboard is actually on the ceiling,wild guess it is,redneck style,rough cut with a jigsaw trim up with a padsaw

 

[Spark plug]

If your really set on a hole saw you could make one, should work in theory.

Call at your local steel supplier with some chocolate hobnobs and barter for a big old band saw blade, one about 2” deep and about 6 tpi. Carefully weld to a disc of 3mm sheet so as not to loose the temper in the blade. Mount an arbour in the centre and should be good to go.

 

[Barlidge]

You dont say if the plasterboard is actually on the ceiling,wild guess it is,redneck style,rough cut with a jigsaw trim up with a padsaw

I'd say it was as he referenced loft insulation

 

[Shedendman]

I'd say it was as he referenced loft insulation

One had to ask,you never know