Drilling Flint.

[Dobedo]

Hi I’m refurbishing an old cottage with some about 450mm thk flint (with brick banding) walls. As part of it I’m reforming and partially repositioning the bathroom with means I need to form new holes thro the flint walls for the bath and whb wastes. Has anybody got any advice for the best way to drill the holes - apart from moving.

 

[Ben-gee]

Go through the brick banding.

 

[steadyon]

Diamond core drill is the only way to go if you can't go through the brickwork.

 

[ShaunCorbs]

Core and take your time wasted I would drill a 2” hole and sleeve it with 2”

 

[Chuck]

There are companies that specialise in this sort of work. My advice is to use one. Google 'diamond drilling ***' where *** is your county or town.

 

[snowhead]

I'd agree with chuck, professionals time and if you got any other holes planned in the future, get them done at the same time, even if it's just a hole for an outside light.

You'd need to buy some good quality core drills to DIY, not the typical Ebay / Screwfix ones

 

[gpbeck]

Basically to get a straight cut drill has to be fixed rigidly to the wall first using specialised frame to stop it wandering off.

 

[Ben-gee]

Last week I spent 5 hours getting a
65mm core through a 550mm stone/cob wall that had flint bits in it - it was going well until I hit the last 200mm which was saturated.

I’d have gladly paid someone with better equipment to do it for me... live and learn.

 

[ShaunCorbs]

Last week I spent 5 hours getting a
65mm core through a 550mm stone/cob wall that had flint bits in it - it was going well until I hit the last 200mm which was saturated.

I’d have gladly paid someone with better equipment to do it for me... live and learn.

water feed is a must esp if the stone is wet

 

[WC1]

You can hire "Hatton garden" type hilti drilling rig widely but iiwy I'd get someone in.

 

[Ben-gee]

So is that with a different core bit, I have standard dry castellated bits - I think the damp makes a paste that gets into the cut groove and jams the bit which is then a pig to remove.

 

[WC1]

Imo you want it dry, preferably with dust extraction or wet with a proper wet rig, as you say damp is the worst of both worlds.

 

[ShaunCorbs]

So is that with a different core bit, I have standard dry castellated bits - I think the damp makes a paste that gets into the cut groove and jams the bit which is then a pig to remove.

same bit it’s the heat that drys it out and makes it stick to the core if everything is kept wet and cool nothing sticks

 

[Ben-gee]

Nice set up (😪, jealous).

Does the water feed down the centre of the core?

Make model cost of rig?

 

[ShaunCorbs]

Nice set up (😪, jealous).

Does the water feed down the centre of the core?

Make model cost of rig?

yes water feed is down the centre just found another pic

diaquip I think I paid around 1500 for the kit including the cores

 

[Ben-gee]

Ah I see, water attaches to drill, so can’t just use my core drill with the clamp rig- shame.
I think my set up around 500, but when it next needs replacing I will seriously consider this - possibly go halves with a pal of mine ( or charge him to use it in future!)
I guess it makes a fair old mess, still bit of Dpm to control that should be ok and it looks a lot physically easier than wrestling with mine.

 

[ShaunCorbs]

Ah I see, water attaches to drill, so can’t just use my core drill with the clamp rig- shame.
I think my set up around 500, but when it next needs replacing I will seriously consider this - possibly go halves with a pal of mine ( or charge him to use it in future!)
I guess it makes a fair old mess, still bit of Dpm to control that should be ok and it looks a lot physically easier than wrestling with mine.

an old f and e tank with a hose or wet and dry vac would work wasn’t bothered in the above pictures as the floor didn’t have any dpm so was damp all the time

 

[Dobedo]

Thanks for all the advice - it’s great that people take time to answer. I think I can get the whb waste tho a bit of brick banding. I’ll have to have a look at diamond core drilling companies too, to be honest I didn’t think that it would be an option with a small domestic project. Thanks again.

 

[gmartine]

You may also be able to hire a wet n dry core drilling kit if you fancy a go, still half a metre of brick is alot of brick to get through no matter how soft.