Drilling a perfectly horizontal, level hole. How?

[ToughButterCup]

I need to drill four perfectly horizontal, that is level, holes through a wall. They need to be level because I'm hanging a Juliet balcony from four stainless steel threaded bars.

 

When I have problems like this to solve, my first port of call is almost always YouTube. There are plenty of videos about drilling perfectly vertical holes and only one or two poor quality videos about drilling perfectly level holes.

 

Is there such a thing as a jig which would help me drill a perfectly horizontal hole through a wall? Or do I need to make my own jig to do that?

 

Part of the problem appears to me to be how to make sure that the drill bit is perfectly horizontal (level) all the way through making the hole. 

 

Is there some tool I could  hire to help me get the job done accurately?

 

This is the kind of job that needs to be correct the first time I do it, not the last time I do it as usually happens

 

 

[Conor]

I've one of these and it's excellent. Very little play or wobble. Used it to drill precise holes in a stair stinger for metal pole ballusters. There are cheaper versions available.

 

https://www.axminstertools.com/ujk-technology-drill-guide-with-10mm-chuck-106072

[TonyT]

Get someone to stand bedside you with a torpedo level on the drill bit before you start. 
 

they can look at the drill bit to ensure it’s going level if you aren’t confident drilling

[AdamSee]

18 minutes ago, TonyT said:

Get someone to stand bedside you with a torpedo level on the drill bit before you start. 
 

they can look at the drill bit to ensure it’s going level if you aren’t confident drilling

I second this. Another pair of eyes shouting up/down to keep the bit level works well. Using a longer drill bit helps the other person spot if it's going off horizontal. 

[Pocster]

A diamond core drill fixed to the wall on a jig would achieve this kind of precision.

[MikeSharp01]

+1 to the torpedo level. If you think about it you don't need the holes to be dead level, they just need to come out of the wall in the right place, so drill from the outside, I guess where the balcony is attaching. The slop in everything will do the rest. Also if you want level you actually need perpendicular - IE at 90 degrees to the wall in both planes.

[ToughButterCup]

49 minutes ago, Conor said:

I've one of these and it's excellent. Very little play or wobble....

 

Thanks @Conor 

With 210mm of travel on the jig , and since the concrete is on the inside (so to speak) of the block,  it makes more sense to  drill from inside - out. The blocks are  300mm thick (of which 110mm is concrete - the rest is insulation).

I have a feeling that there's going to be a lot of measuring and re-measuring.

 

1 minute ago, pocster said:

A diamond core drill fixed to the wall on a jig would achieve this kind of precision.

 

Yes, @pocster, something industrial like that appeals to me. Its the jiggy thing that defeats my imagination at the moment.

[ProDave]

I first question WHY in needs to be perfectly level?  That is not such a stupid question as it sounds.

 

The holes obviously want to end up on the outside exactly right to line up with the holes in the Juliet balcony.  But to ask for the holes to be perfectly level implies the fixings on the inside will be visible, so they too also need to be in just the right place.  If so not only do the holes need to be perfectly level, but also perfectly perpendicular to the wall.

 

If the internal fixings are not visible when finished then only nearly level and perpendicular are required.

 

Also what are you drilling through?  I assume ICF walls, so the start of the drill will be soft material, it is when you hit the concrete core that the drill is likely to be thrown off course?

[ToughButterCup]

1 minute ago, MikeSharp01 said:

... If you think about it you don't need the holes to be dead level, they just need to come out of the wall in the right place,...

 

@MikeSharp01, I'm trying hard to avoid being told that I'm over-thinking stuff AGAIN.

 

I'd like to qualify what you say to 

'... they just need to come out of the wall in the right place and heading in the right direction....'

 

because (over 400 mm: 300mm block + external wall fixing) a one degree error would be enough to make me swear.

[Pocster]

7 minutes ago, ToughButterCup said:

Yes, @pocster, something industrial like that appeals to me. Its the jiggy thing that defeats my imagination at the moment.

My late father used to do diamond core drilling for a living many years ago . The jig comes with the drill . You bolt that to the wall ; insert the drill . Check it’s all level and off you go . It was ( of course ) hilti gear .

 

https://www.hilti.co.uk/content/hilti/E1/GB/en/products/homepage-and-new-products/diamond-coring/diamond-drilling.html

[ToughButterCup]

2 minutes ago, ProDave said:

...

Also what are you drilling through?  I assume ICF walls, so the start of the drill will be soft material, it is when you hit the concrete core that the drill is likely to be thrown off course?

 

Exactly.

I want to mitigate the potential for error by drilling from inside - out. The block has 40mm of 'wall' and then 110mm of concrete, the rest (on the way out of the house as it were)  is insulation and so won't be likely to affect the direction of the drill.

 

I've made an exact template of the glass juliet balcony, so all I have to do is to line up the centre lines of the door (currently a suicide door) and the glass balcony: and drill .....

 

Thanks @pocster, thats the principle I feel like using:

• mark out using the template
• fix a decent jig to the wall  (the drill-guide as @Conor above suggests)
• adjust the drill guide for level and direction (torpedo level; thanks @TonyT and @MikeSharp01)
• take my prayer-mat out, face east
• drill
• swear 
• repeat

 

 

[ProDave]

Is the Juliette balcony permanent, or just to get sign off?  Will there be a real balcony later?

[Conor]

Another option is to make the hole a bit bigger than needed (e.g. if a 12mm bolt, then a 14mm hole), partially fill with anchor resin, then insert bolts and get them perfectly aligned before the resin goes off. I'd say that's the easiest and fastest way. It'll only cost you a tenner for a tube of resin. I'd also consider cutting away a block of the EPS that's slightly bgger than the patch area. I'm assuming you'll be doing this as I doubt the balcony is fixed agains the face of the EPS?

[MikeSharp01]

27 minutes ago, pocster said:

It was ( of course ) hilti gear .

Was that the kit that drilled those holes into the vault for the Hatton Garden job?

[Pocster]

16 minutes ago, MikeSharp01 said:

Was that the kit that drilled those holes into the vault for the Hatton Garden job?

Might be ! Should be suitable for a Juliet balcony.

[Pocster]

As incredible as it sounds when I was a teenager I would go with my dad on jobs ( yes I learnt nothing ) .

Once I recall at airbus we had to core a 3 metre hole ( tunnel more like ) at a specific angle through reinforced concrete . Rig bolted to wall . Drill back then was mofo heavy and needed 2 of us to get it up there . Took our time ( water pumped to the tip ) . Would have taken a few hours . But we took all day so my old man could charge 3k ! - that must of been 35 yrs ago . But no one else could achieve that and certainly not at that price . It was super specialised gear at the time . I got paid 30 quid 🙄🤣

[Iceverge]

@ToughButterCup

 

How about just drilling a block of timber first on the bench at 90deg and using it as a guide to get the hole started. 

 

 

[ToughButterCup]

3 hours ago, Conor said:

Another option is to make the hole a bit bigger than needed (e.g. if a 12mm bolt, then a 14mm hole), partially fill with anchor resin, then insert bolts and get them perfectly aligned before the resin goes off. I'd say that's the easiest and fastest way. .....

 

Anyone ever told you, you're a genius? 

 

I'll need to think of a simple quick way of holding the threaded bar in exactly the correct alignment.

 

How hard can that be? 

Yep, overthinking again I expect. But it's fun.

Stops me feeling sorry for myself having worked as a renderer's bitch all bloody day yesterday. My back is Killing me.

 

6 minutes ago, Iceverge said:

@ToughButterCup

 

How about just drilling a block of timber first on the bench at 90deg and using it as a guide to get the hole started. 

 

You assume @Iceverge that the wall is perfectly vertical in all eight ( two balconies) drilling spots. Naaaah, they ain't.  Its the obious quick answer though. Thanks.

[Iceverge]

4 hours ago, ToughButterCup said:

You assume @Iceverge that the wall is perfectly vertical in all eight ( two balconies) drilling spots. Naaaah, they ain't.  Its the obious quick answer though. Thanks.

 

Drill 10mm into the wall free hand. 

 

Then put the block in place and with 2x normal wood screws through it adjust them to push the block into level using a spirit level. 

 

Then finish drilling the hole correctly. 

 

 

[MikeGrahamT21]

Seen people putting a spanner on the drill bill if you are going free hand, if you are level it shouldn't move

[ToughButterCup]

1 minute ago, MikeGrahamT21 said:

Seen people putting a spanner on the drill bill if you are going free hand, if you are level it shouldn't move

 

Yes, I've seen a video of that technique.

There's another similar video of someone who suspended a large open-faced hook on the drill shaft; lean one way and the hook travels towards the wall face, lean the other and the hook slides towards the drill. 

 

That's a good quick check, useful for things like large fence posts - but it has one disadvantage: it can't check for lateral accuracy. 

 

With all this excellent advice, I'm going to have to drill some perfect holes aren't I ?

I'll drill some test holes as soon as I get the jig. And post here.....

 

Thanks very much everyone.

[saveasteading]

Yet another idea.

Firstly if you go with the oversized hole, check there is no advice on the tube against this. My instinct is to use the least amount of resin for quick transer of load to masonry.

To overcome that concern, there are mesh inserts which i think have some flexibility.

 

I would do the opposite. Use a smaller pilot hole, then check it for level by torpedo level on the bit or a dowel. Then the next bit can be aimed up of down as appropriate.

The smaller hole also makes it easier and more controllable with a normal drill.

[ToughButterCup]

Hmmm, yes, I thought about that. It strikes me that I'll have the opportunity to make a deliberate mistake with a small diameter drill and then see how easy (or otherwise) it is to correct it.

 

I'll drill some experimental holes on the piggery to see what happens.

[Pocster]

It’s funny how something apparently relatively simple requires some over thinking . That’s not a criticism! . I can mull a ‘simple’ problem for hours /days/weeks/years . Then what tends to happen is either it was easier than I thought or I (expletive deleted) it up .

[SimonD]

10 minutes ago, pocster said:

It’s funny how something apparently relatively simple requires some over thinking . That’s not a criticism! . I can mull a ‘simple’ problem for hours /days/weeks/years . Then what tends to happen is either it was easier than I thought or I (expletive deleted) it up .

 

Yeah, you're not the only one. It's a lonesome journey and worse when you get in your own head. I've just got into the same situation because as soon as I decided to put my trust in getting in some trades and paying someone instead of doing it myself, the carpenter has cancelled to sets of dates and gone awol when we had an agreed timeframe - now I'm stuck with a load of internal doors about to arrive and figuring out a load of bleedin' logistics and work schedule with me doing the stuff myself again. (expletive deleted) trades!

 

As for the hole situation, I think it's easiest to drill a larger hole, adjust the fixings and then use an epoxy cement to set them correctly. Even with a press, if your drill bit is long and fairly thin, you're going to get some wander through a thick wall. I have a 1m 16mm sds drill bit for getting through my walls and it flexes like crazy. Even a 22mm diamond core drill rarely gives me a clean enough hole to insert a 22mm pipe afterwards either. But then maybe I'm just rubbish at drilling holes.......