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.