There is nothing quite as dirty, dusty, and plain-old tough as demolition work, especially for breaking up concrete and masonry. The work is unpleasant enough for both the crew and the tools so we try to get it over with as quickly–and as painlessly–as possible. But here in New York City, a town basically encased in concrete and rock, it's nearly impossible to avoid; we find ourselves starting virtually every job with heavy demolition. Our tool of choice for this work is the 20-pound demo hammer. It's heavy enough to break up hard stuff but versatile and light enough to work in a variety of positions and locations, and it still fits in the truck or gang box at the end of the day.
On my sites, we break out–and through–a lot of concrete, block, and stone. We've tried heavier breaker hammers for this work, but they're too heavy and can often do more harm than good, sometimes resulting in busted pipes and cracked ceilings in the spaces below our projects. Plus, they're tough to store.
Hammers weighing between 18 and 22 pounds, however, hit the sweet spot. Their power-to-weight ratio provides the oomph we need for breaking up over-poured slabs and the agility and balance it takes for tough breaking jobs and surface cleanup. We sentenced five tools to 10 long weeks of jobsite testing: the Bosch 11316EVS, DeWalt D25900K, Hilti TE 805, Hitachi H60MRV, and Makita HM1202C.
We looked for raw power in straight-down jackhammer-like applications. Then we used them in front and overhead positions for break-through work opening block walls. We also used them in various positions for breaking down stone walls and cleaning up concrete surfaces where we sought the best-balanced tool with easy access to switches. Anyone who has worked with these tools also values vibration-dampening features, which we noted throughout the test cycle, as well as user-friendly bit-change mechanisms and kit boxes.
If a demo hammer doesn't have the knock-down power we need, all the balance and ergonomics in the world don't mean as much, so we hit them with the power test right from the start. We looked for raw strength first then comfort and vibration in some of our toughest straight-down chipping applications. We removed concrete topping (a 4-inch concrete layer on top of the slab) from an old building for a sixth-floor condo renovation. Think mountains of nearly 100-year-old super-hard concrete and days of chipping and you'll get the idea.
Straight-Down Power. After several days of straight-down chipping and several tons of busted up concrete, we found that the DeWalt performed best followed strongly by the Hilti. Each of these hammers broke through the topping and provided us with the chipping power we needed to muscle through. The Bosch and Makita had good showings, too, making quick work of the over-poured slab. The Hitachi seemed to lack the punch we were looking for even though it was one of the heaviest tools tested.
Body Type. The test group included tools with two different body designs, which also seemed to play a role in how they performed. We liked DeWalt's in-line design, which is similar to its larger cousin the jackhammer. With the bit and motor in line with the handle, it has good balance and control. All the weight is in line with the bit, which we felt helped it deliver all the punch directly to the working end.
The other tools' motors are offset from the center line of the tool. While we don't have the scientific equipment to quantify how this affected performance, our jobsite experience indicated that the tools with offset body designs had to work harder to remove material.
Bit Change. Breaking out an over-pour, as you would expect, we went through a lot of bits (see "Iron," page 56). Lifting up a 20-pound–plus tool and struggling with bit change is a sure way to get guys frustrated and slow the crew down. Thankfully, most of these tools have good systems, but some are better than others. We found the Hilti's bit change flawless and very easy to use. Bosch also has a good chuck but needed a little more effort than the Hilti to use. DeWalt and Makita came in a close third. Hitachi rounded out the pack with the most difficult bit change.
All the tools except the Hilti accept SDS Max bits; Hilti's accepts the company's TE bits.
Bit Rotation. All the tools tested allow you to rotate spade bits to customize the bit's orientation to the tool and the work for maneuvering in tight quarters. While we rarely use the feature, it's nice to have when you need it. The Bosch, DeWalt, Hitachi, and Makita require sliding a ring in the chuck back, then twisting the chuck to position the bit head. Detents let you know when the chuck is engaged. Hilti's octagonal TE bit works differently: To rotate it, you remove it and reinsert it into the chuck. Even though this does require an extra step, we use the feature so little that it's not a big deal. And, fewer moving parts in the chuck may prove beneficial in the long run.
Ergonomics & Finesse
"Ergonomics and finesse" of a demo hammer sounds like an oxymoron until you start comparing the tools in projects other than straight-down blasting. We used each hammer to clean up edges and chip out the concrete around pipes, conduits, structural steel, chases, and finishes–situations that are not a matter of power, but more about ease of use and control. It's a good idea to dial-down the power around these breakables to help control the tool, so access to switches and controls is also key in this work.
DeWalt has good, accessible power controls, and its in-line body provided nice balance in various working positions. The power dial is easy to read and reach. It's also large and accessible enough to use with gloves on or off. Hilti, Makita, and Bosch all have adequate controls and nice balance. The controls were easy to reach and use, wearing gloves or not, while each tool was comfortable to use. Hitachi's controls were very difficult to read and access, and they are recessed in such a way that they are exposed to collecting dust; the balance wasn't what we were hoping for.
After demo-ing the floor, we moved on to chipping-out openings in walls and chipping overhead. This is where power switch location is critical and the tool's balance is doubly appreciated. No one wants to be fumbling around to hold a tool or for the on/off switch with a 20-pound vibrating tool overhead.
Again, we liked the DeWalt's controls and feel. The balance was great and the pistol-type trigger on the inside edge of the grip was easy to turn on and off while keeping our hands where we normally grip the handle.
Bosch and Makita also had a good feel to them, though they employ different switches. Bosch's large slide trigger was easy to activate/deactivate, and Makita's bar trigger engaged well. Hilti's balance was nice, too. The power switch could be better located, but the power level control was good. Once again, we thought Hitachi's design was lacking: the balance wasn't what we'd hoped for and the switch was tougher to use than we'd hoped.
Vibration. Tool companies take two basic design approaches to combat vibration in this category of demolition hammer. In the first, on the Bosch, Hilti, Hitachi, and Makita, no single item specifically works on vibration, but parts and features–like balance, rubber bumpers, padded grips, and isolation of the vibrating parts from the non-vibrating parts–work in unison to manage and control how much the tool shakes around. Within this category, each company details its tools differently, but the approach is the same. The second method is DeWalt's patented Anti-Vibration Control, which is a torsion spring–based mechanism that fits inside the hammering mechanism of the tool.
We really became aware of how these approaches played out on site while working in front and overhead because these applications really bring home every wiggle and vibration the tool makes. Hilti's handle and design provided the best cushioning and dampened the vibration quite well. DeWalt also paid attention to this issue with a nicely padded grip. The Bosch, Hitachi, and Makita all had suitable handles and grips.
Boxes. Good toolboxes are always important, but with 20-plus–pound hammers–plus bits–it's even more important; these tools require a box that can withstand not only the weight of the tool banging around but also a collection of heavy bits, which altogether can reach 30–40 pounds.
Fortunately, the boxes in this group were up to the task. All are plastic but are made tough enough to hold the weight. I liked the Hilti, Hitachi, and DeWalt boxes best. They're all big enough and have ample room for extra bits. Hilti's box top and bottom are identical, making upside-down box opening a regular occurrence. A duct tape X on the top solves this, though. The Bosch and Makita boxes worked fine, though I wish they were a little roomier. The best news is that all the boxes' interior tool-positioning tabs are clearly laid out, making it easy to get the tool back into the box.
This tool test sets the record for the biggest Dumpster bill of any I've done. We broke up tons of concrete, block, and stone over weeks of working these hammers hard.
We liked the DeWalt model the best–it's a great all-around demo tool. It has very good balance and we like the in-line body design. All the controls are in the right place and vibration is well-dampened. We also liked the Hilti. With its heavy-duty construction it should endure the test of time, which is something to consider when you see its higher price. It's got a great bit change and the best vibration-dampening.
The Bosch and Makita came in a very respectable third. These are well-designed tools with plenty of power and were quite comfortable to use in various positions and materials.
Hitachi's new tool didn't seem to have the power and performance we need.
–Erik Elwell owns Thompson Construction, a high-end residential and light commercial remodeling firm in New York City.
We use all kinds of different bits or irons on our jobs. For starting in on a slab, we usually chuck up a bullet-point bit to dig a starting hole. Once we have the hole, we switch out for a spade bit. Depending on the concrete's density, we opt for 1- to 3-inch chisel; the softer or more brittle the concrete, the wider the chisel. For cleanup work and brick demo, we usually keep to a 1-inch bit because it provides the most control. When removing tile from a mortar base, we generally use the widest spade bit we can find. Four- to 5-inch spades generally get the job done in a hurry.
Thanks to Dril-Tec for supplying the bits for this test.