How do you know if a drill is too lightweight for a heavyweight job?

Question

I work in a steel door factory where I work mostly in the assembly department where I use drills and angle grinders. The management is cool enough to let us borrow the tools for home projects so I sometimes bring them home.

I decided to replace shower head holder on the ceramic tile bathroom wall since one of the plastic holders was broken and other one kept coming out of the wall and causing the shower head to rotate. The plastic anchors of the new shower head holder as I am told require 6mm holes. I also got some anchors for the toilet which wasn't fixed (nor there was silicone) which require 10mm holes.

I decided to take CatPower 5920 (920W/980RPM/5180 Impacts Minute) rotary hammer for the toilet business and KL Pro KLDM1850B (Torque 60Nm/28800 Impacts Minute/1800 RPM) for the shower head holder business. My boss told me KL Pro would get a blown engine and told me to take DeWALT DW112S-QS instead (which I won't use anyway since it's not a hammer drill). So I got CatPower and some extension cord and a tape measure for the job

I got some cheap really cheap masonry drilling bits and I guess I will be doing the job. What I am wondering is, there was a jack of all trades/departments (master of fitna and spying) kid at the factory that no matter how I and everyone else told him a DeWALT 18V battery drill that doesn't even have impact isn't suitable for 10mm holes to 1mm thick door frame steel but he would keep doing it non stop anyway.

Would the KL Pro be useful for drilling couple holes to the ceramic tile wall and into the concrete behind? The anchors require 6mm of diameter and 30mm of depth and there is only two of them. I am assuming CatPower won't have many issues drilling a couple of 10mm of diameter and 43mm holes into the ceramic tile floor and the concrete under that.

How does someone know if a drill is just not powerful/durable enough for the job?

Answer 1

When drilling through tile, it's possible to use a hammer drill or a SDS rotary hammer, but the hammer action needs to be turned OFF with the appropriate knob. Otherwise, in the best case you'll get a lot of tile chips on the edges of your hole, and in the worst case you'll get a cracked tile.

1. Ceramic tiles, ie just a thin layer of hard stuff, then 5-10mm of ceramic.

First mark the hole with a pen and put on safety glasses. Now it's just like using a hole punch on metal, you need to make a dent in the tile otherwise your masonry bit will walk all over the place. You can use something pointy and sharp like a drywall screw and tap it gently with a hammer to take out a very small chip of tile.

Then you drill slowly with the masonry bit. Any drill will do, it's not about torque, you're just grinding the tile with a carbide bit. It just takes a couple tens of seconds. It's better to go slow because it'll heat, and to make sure it doesn't wander away from where you want the hole.

2. Porcelain tiles, ie 10mm of super hard stuff

In this case you need a diamond bit. If you have a lot of patience, it's possible to drill these tiles with a masonry bit, but you'll need to spray water on it, because it's going to take a while, it'll heat a lot, and it'll wear down your bit. Since it's not possible to "aim" a diamond core bit, I just use a wood board as a guide: just drill a hole in it with the same diameter as the diamond bit, put the diamond bit through, and it will act as a "handle" to keep the bit where you want the hole to be.

In both cases it's not about torque so any drill will do the job. SDS hammer is fine (with the hammer turned off). If there's concrete behind, then after you're through the tile, just turn the hammer action on.

If there's plaster behind the tile, I just use the lightweight 18V drill. I only use the big 18V drill for the 68mm diamond core for electrical boxes.

Hammer drill tends to have too high RPM and melt your bit if you're not careful.

How does someone know if a drill is just not powerful/durable enough for the job?

Simple, since you're asking about masonry:

Hammer drill: useless (unless that's the only thing you have on hand), makes a lot of noise and not much holes.

SDS hammer: perfect for concrete, brick, etc. Look at the impact energy in joules to check how fast it'll drill. 2 Joules is good for most stuff and not too heavy, works great up to 10mm, but gets really slow at 20mm (ex: Makita DHR243, 2J, 3.4kg). If you want a 25mm hole 500mm deep into concrete, get a drill with more Joules (like 4-8J) but it will be huge, a lot heavier and impossible to hold with one hand while on a ladder. If you want to drill many small holes while holding it with one hand on a ladder, there are smaller lighter ones for that ex: Makita DHR171, 1.2J, 2.1kg).

For SDS, torque isn't important, in fact you want a clutch that will limit torque and not break your wrist or throw you off the ladder when the bit gets stuck.

Any 18V light drill: absolutely fine for plaster, or tile over plaster.

Answer 2

Any non-toy hammer drill should be able to drill into concrete... eventually. That task doesn't seem to require huge amounts of torque, but it does take time.

I have an old 14v Porter-Cable -- mid-quality, from a time when drills were less power-efficient and with ni-cad batteries which have lost a lot of their capacity -- and the only problems I've had drilling concrete (with the appropriate but, of course) were with having to stand there leaning on the drill and having to swap/recharge batteries repeatedly for every 2" deep hole.

As fast as drilling tile goes... my instinct is that hammer mode would be the wrong tool for that task, but not having tried it I have no valid opinion.

Answer 3

Drilling through tile as well as any other surface depends more on the bit than the drill. I have drilled through hard floor tile and concrete with a small 12V drill with the proper bit. Now if you start to get to the bigger things, like drilling a 1" hole through a concrete wall...well the bit for that simply will not fit into a small drill.

My father brought home a few old drills used in an operating rooms to drill through bone. Those things were so sharp and hard I could drill into plastic and some metals just turning them between my fingers!