Stop drill from wandering

[Jupiter01]

I’ve had issues in the past when drilling into blocks (porous type). The hole ends up a lot wider than desired which causes failed plugs and fixing. I’ve used drill mode instead of hammer action.

How can I avoid this when drilling for a TV bracket today please?

Thanks in advance

 

[blup]

Turn off percussion (use cordless drill not sds) and make a small pilot type hole with a bradawl or similar. Start with smaller drill bit and build up sizes.

If it's soft block you will probably be able to drill the entire hole on rotation only.

Blup

 

[Jupiter01]

Thanks @blup. Is percussion the same as hammer action?

 

[blup]

No problem, in practice hammer and percussion are different but achieve the same result i.e. linear force to supplement rotational force. SDS drills have a true pneumatic hammer (or piston) action; with percussion two plates rotate against each other causing the drill chuck to move back and forward, and is what you find on traditional corded drills.

Blup

 

[Jupiter01]

My holes need to be 10mm. In the "build-up" approach, how many increments should I introduce?

 

[Diver Fred]

3, 6, 10mm

 

[Ian H]

I bet a 10mm HSS bit would make a nice neat hole in those blocks.

 

[SFK]

If soft material, I sometimes use up to 8mm drill to full depth, and 10mm drill only to say 20mm depth. That way head of rawplug is in 10mm section and narrow bit of rawplug is in 8mm section, and when screw is inserted it all fits tighter into hole.
Anyone else do this?
Sfk

 

[blup]

My holes need to be 10mm. In the "build-up" approach, how many increments should I introduce?

I would start with a small diameter bit say 3 or 4mm. That might give you enough to go straight to 10mm, it's a matter of judgement.

By drilling the first 30 or 40mm carefully you will create a sufficient "guide" for the rest of the hole.

Blup

 

[blup]

If soft material, I sometimes use up to 8mm drill to full depth, and 10mm drill only to say 20mm depth. That way head of rawplug is in 10mm section and narrow bit of rawplug is in 8mm section, and when screw is inserted it all fits tighter into hole.
Anyone else do this?
Sfk

I gave up using the rawlpugs years ago, if you mean the hard plastic brown yellow and red plugs - they would often spin in the hole, so I tried nylon plugs like Fischer. If it works though that's all good.

Blup

 

[SFK]

Blup,
As you suggest, I always use nylon plugs now, so much better. But still call them rawlplugs. But even with these, with soft walls I make a champhored hole so narrower at the bottom.
Sfk

 

[^woody^]

What you are doing is taking too long to drill the hole and not being at a height where you are able to hold the drill comfortably and horizontal. But the main thing is, just press the drill in on hammer, and pull it back out quickly and don't mess about with it.

And get someone else to hold the vacuum hose right under the hole, until you have mastered holding both.

 

[pilsbury]

My favourite is drilling into a plastered wall only to find yourself right on the edge of a brick and this then pushes your drill into the softer mortar..... always makes me giggle.

 

[^woody^]

My favourite is drilling into a plastered wall only to find yourself right on the edge of a brick and this then pushes your drill into the softer mortar..... always makes me giggle.

Why don't you just start drilling 10mm to the side then.

 

[pilsbury]

Why don't you just start drilling 10mm to the side then.

I was talking about the bottom edge of the brick.....