2015 has made itself out to be the “Year of High Torque Cordless Drills”. We’ve put our hands on three distinct systems that have over 1,000 inch-pounds of torque to offer. Each drill is compelling in its own right, but the Hilti SF 10W-A18 has set itself apart with its 4-speed gearing system. It boasts a torque rating of 1,062 inch-pounds.
We first previewed Hilti’s 4-speed wonder at World of Concrete back in January. Its ability to chew confidently through wood impressed us to no end. This drill features an intentional design at low speed. At just 310 RPM it lets you mix without burning up the motor. Don’t try that with typical cordless drills!
Now we have one of these beasts in-house to use a bit longer and really get to know. Hilti recommends drilling applications with hole saws up to 6″, HSS bits up to 1/2″ in metal, and spade bits up to 1-1/2″. That’s pretty ambitious for a cordless system, so let’s put it under load and see what we can accomplish.
I’ve got a series of hole saw, spade bit, and wood-boring bit applications to put the Hilti SF 10W-A18 to the test. I don’t want to push it to its absolute limit though. My goal is to see if it will make common high-stress applications easier on the user. After all, what’s the point of 1,062 inch-pounds of torque if all it does is beat up your arms?
Hilti SF 10W-A18 First Second Impressions
They say you never get a second chance to make a first impression, but… Well, they’re right about that. Nothing surprised me when I took the Hilti SF 10W-A18 out of the box this time. However, I did get a chance to take a closer look at the overall design.
Build quality is outstanding. I have yet to put my hands on a tool from Hilti and have a negative thought about its durability potential. The drill has a weight giving you confidence that should you open the housing, you’re going to find solid metal gearing and quality components. At 6 pounds, it’s not going to win the cordless drill bikini contest, but it’s going to make a run at the bench press competition.
The sleek design features rubber overmolding that improves the grip comfort and security. It extends up and around the back of the drill to protect the housing. The Hilti SF 10W-A18 is well-balanced with a battery installed. You’ll notice that the handle is more centered than traditional drills. This doesn’t really affect the ergonomics one way or the other from what I can tell. It comes with a side handle that you will absolutely want to have installed when you’re using hole saws, spade bits, or other potentially biting accessories. There’s more than enough torque here to do some serious damage to your arm.
Hilti SF 10W-A18: Are Four Gears Necessary?
Okay, common thinking makes you wonder – if I need four gears, why didn’t someone do it before? That’s a great question, so let’s dig in! I took several common applications to each of the 4 gears to see what reasonable in each. Like you’d expect, there’s an inverse relationship between speed and torque – you have to decrease one to increase the other.
4th Gear: 2100 RPM
High speed is where the majority of your wood drilling applications are going to take place. Wood-boring is another story, well, gear. I also found that there was plenty of power here to run all of my spade bits up to the largest 1-1/2″ size. With the largest couple of sizes, it was hit or miss on breakthrough. I could always back it out and finish the hole, but sometimes it simply didn’t have the torque to break out the other end. With other drills, I’m usually good up to 1″, then have to switch over to low speed for the larger diameters.
Big hole saws are scary at 2100 RPM. I doubt you’ll find a manufacturer that has a speed recommendation this high. Still, I wanted to see what would happen. A 4-1/2″ hole saw was difficult to control at this speed. Backing out several times, I was able to make it through 2x material, but this gear is not where you should be doing hole saw work in wood or metal. The story was the same for a self-feed wood bit – it was very hard to control at this speed.
4th gear really should be reserved for running your standard wood drill bits.
3rd Gear, 1210 RPM
Third gear is the sweet spot for wood boring. Hole saws, self-feed bits, and spade bits all drove with confidence and control in this gear. If you’re fortunate enough to use self-feed spade bits or other self-feed bits, you’ll find that the Hilti SF 10W-A18 Drill is incredibly well-tuned in this gear. Even if your bits aren’t self-feed, there’s an excellent combination of speed and torque for wood boring here.
2nd Gear: 530 RPM
Hilti’s 2nd gear is most brands’ low gear. This is where you’ll want to tackle metal drilling applications. You’ll get the torque to break the metal on metal friction while keeping the RPM’s up enough to make consistent progress. You can use wood boring bits in this gear, but there’s so much torque available it’s really not necessary. I found the tear out in wood to be worse with the slower speed and higher torque in this gear.
1st Gear: 310 RPM
With the highest torque and slowest speeds available, mixing is done in 1st gear. It’s a nice feature to have, but it’s not the only application taking place. Hole-making in metal with hole saws requires relatively slow RPM’s. Take a look at any manufacturer’s recommendations, and you’ll find that this is the gear you want to work in – and that other drills should have. Most of the bi-metal hole saws I work with are designed to be used at 100 – 200 RPM against metal. It’s much easier to be near that recommended speed in 1st gear than it is second.
Hilti SF 10W-A18 Key Features
- Corded performance on a cordless platform
- 4 speeds
- All-metal gears
- High-efficiency motor
Hilti SF 10W-A18 Specifications
- Voltage: 18 V
- Battery type: Li-Ion
- No load speed: 2100 rpm
- Max. torque (hard joint): 1062 in-lb
- Max. torque (soft joint): 637 in-lb
- Number of gears: 4
- Motor brake: Yes
- Dimensions (LxWxH): 10.4 x 3.6 x 10.2 in
- Warranty: Lifetime service and Fleet management service
- Price: $495 (Kit), $199 (Bare Tool)
Conclusions
Controlled power – that’s the feeling I’m left with when I set the Hilti SF 10W-A18 down for the day. Tackling high-stress applications by transferring incredible power smoothly without tearing your arm out of the socket is great. That’s not all there is. Where the drill really sets itself apart from other 1,000+ inch-pound torque drills is in that 1st gear. The controlled ability to mix thinset or mortar without burning up the drill breaks through a barrier that’s existed for a long time. Once again, Hilti delivers outstanding performance that simply places it on another level altogether.
