core drilling 162mm for kitchen extractor vent

[NHW]

instructions on my vent - eiQVENTKIT150COWL - Say that a 162mm minimum hole size is required for the kitchen vent.

I already have a trusty Titan TTB631SDS which has a safety clutch, but I am told that it shouldn't 'really' be used for doing core drilling, and that 162mm is quite a large size which should be used with a specific type of core drill - Hilti 110's / Makita DHR242Z etc. Which for drilling 1 hole I would not see the return in buying outright, renting I think is around £90 a day approx.

Not many places also have a core bit which is larger than 150mm, so the 162mm core bit I am just thinking to go and buy anyways.

https://www.toolstation.com/mexco-premium-slotted-dry-diamond-core-drill-bit/p30062

I'm just wondering if its just moreso a suggestion that you cant use the Titan for this type of job and that if you basically just take your time and go slow it would be alright. Its just for a normal residential property so brickwork, blockwork and a cavity. Thank you for any advice in advance

 

[Murdochcat]

I had a 6” core drill and very rarely used it. Having said that when I needed it I had it in my garage

 

[thomp1983]

The titan will do it, to make it easier on the drill I'd start the core and once the core bit is about 15-20mm into the wall remove the core and use an sds masonry bit to stitch drill all the way round the groove the core has created then use the core drill again to finish the hole.

 

[JohnD]

You could hire one, but it will be very heavy, and risky if you are on steps or a ladder.

Your drill will probably go through the blockwork OK, but for the outer leaf it might be neater to take out a few bricks, and rebuilt round the duct. Remember to tilt it so any rain or condensation runs outside.

 

[opps]

I had a cheapo Titan, about 1500w. I used it to drill up to 150mm. Both times I was going through solid 9 inch walls. I started with a SDS drill bit the same size as the pin in the core but long enough to go all the the way through the wall. Although it is not listed as having a safety clutch, I drilled slowly and regularly moved the core back and forth to remove the dust whilst working. Not ideal, but it worked. It did snag a couple of times but the power died immediately. I suspect that I didn't end up with a damaged wrist because the core was so large (preventing the drill continuing). The only time I hurt my wrist was using a 12mm bit which snagged against a metal gate fitting on a brick post. That hurt. Never experienced that when using my smaller SDS drills.

I am not telling you to use your Titan, I am simply saying that I have and lived to tell the tale.

Oh, and I drilled from both sides to prevent breakout. An advantage of using a long SDS drill bit.

 

[opps]

As an aside...

My core drill arbor has a straight centre bit. Diamond core bits are generally intended to be used with hammer action turned off. Why are so many arbors sold with a SDS drill bit in the center?