I have bought old cabinets which I would like to hang on a brick wall. I have marked the spots on the wall, but I find it very difficult to drill precisely, because the drill bit follows a path of least resistance.
What are the techniques and tools required to drill a hole with less than one millimeter between the actual hole and the mark ?
The most important part is to start off in the correct location. Once you have started the hole it's relatively easy to keep straight if you take it slowly and have a steady hand.
If your drill has a variable speed - either via a selector switch or by varying the pressure on the trigger - use the lowest speed possible to start the hole. A drill that uses trigger pressure is best as you can start with the drill bit on the mark and then gradually increase the speed. This prevents the bit skidding on the surface.
Once you have the first few millimetres drilled bring the drill up to full speed. You will need to push but don't use your full weight on the drill.
You might find it useful to have someone else watch so they can tell you if you aren't holding the drill perpendicular to the wall.
If you don't have an assistant you can do various things to help you keep the drill level.
The easiest way to drill brick without the bit moving off the mark is to use a nail/center punch/awl/nail set etc.. to make an indentation on your mark. Take one of the above objects, and place the point on the mark on the brick and tap it with a hammer, this will make a little indentation on the brick that will hold the drill bit in place until it digs into the brick.
This trick also works on tile. The key is not to hit the object into the brick too hard to prevent the brick/tile from damage.
If a bit has strong tendency to skidding to leat resistance path drill pilot hole with high quality bit with three or four blades and with a strong impact drill. When all holes made with pilot are ready fix some plugs and hooks. Now try if all the cabinet hangers match with all the holes. If they do use bigger bit that suit to stronger plugs. If any hole missed its designed location I d use big diamter and chemical anchor. Big diameter allows you to correct the position of the plug precisly within 2-3 mm range. You can insert plastic plug into a liquid chemical anchor as well however its potential load is smaller. Than use longer plugs to get stronger anchor.
Drilling holes in solid brick / cement is pretty easy since you can apply slow pressure to establish the initial drill site (or use a centre punch or nail to start the site point)
The difficult thing is what happens once you start drilling deeper. Where I live, most houses have a plaster/mortar surface with brick inside, On the occasion that the drill point is at the transition between hard brick and soft mortar, the drill will be pushed skew by the varying materials. -- This is a very common issue for me, and no amount of accuracy in the initial site establishment will help.
The only thing to do in this case is:
When I have had an off-centre hole to deal with, my solution was:
drill the hole slightly larger
fill with a wood peg - perhaps glued in
screw into that once dry.
Usually works fine.
Here are a few ideas. If you have enough tools and can figure out how to do it, maybe you can make a jig with a square piece of plywood. Drill a hole the size of your brick but through that. Figure a way to locate the jig so the hile is where you want it in the brick, then start your hole through that. The jig should prevent the bit frim wandering--if you can hold it steady. Also, I didn't notice anyone mentioning a carbide tip bit, let alone a tapping drill. better at least get a carbide tipped bit for this.
I haven't tried this yet, but am facing the same problem.
I'll probably use concrete nails as a hole punches once the centers are located. I may combine this with the suggestion of making a hole template, but accurately drive the concrete nails into the wood so they align to the exact center of a pair of slots.
In my case, since this involves a drainage pipe, I'll place the template with the correctly placed concrete nails on the slab that underlies a brick surface and an aligned curb. (I hope you can visualize this.)
What needs to be mounted is a pipe support of sheet metal. I can,in my case, use clamps to secure the template to the curb and the slab underneath. when all is in place I'll gently hit the nails further into the wood template, thus striking the slab.
Of course the wood template can be any size, dependent on the needs of the project. A level can be run across the heads of the nails in the template for correct horizontal placement when secured to the curb with clamps. In my case a slight down angle for drainage is required. For others double sided tape could be used for accurate placement of the template.
I'll achieve required placement since the adapter in the brick curb will be held in place with GE Silicone II. At this point it is not hot glued to the rest of the pipe, which can be positioned correctly for drainage. Lines drawn through the centerlines of the concrete nails will be used to make additional sight holes to another set of lines on the sheet metal pipe support so the punch marks made by the nails will be in the exact center of the slots. The slots will allow 3/8" of angular slope between the slots in either direction. Thus will also have another allowance for accuracy of threaded rods epoxied into the holes which will be oversized allowing an additional amount of accurate positioning until the epoxy sets.
It sounds complicated, but so is being a little bit off center.
When I had poor quality bits, an underpowered drill and hard old bricks I found I got very precise holes due to the necessary method - starting with a thin bit, and working my way up, eg 4mm then 6mm, then 8mm. This also helped me avoid the “slip” when my drill would hit the edge of some of the dry-wall adhesive
