By Michael Davis
Rookie framers always get stuck with the worst work, like cutting out doorplates and knocking down braces. They also get stuck doing work that's just plain miserable, like nailing off joist hangers. Anyone who's ever been sent into the dungeon to back-nail hangers knows what I'm talking about: trying to drive tiny nails in a confined space over your head. Pneumatic nailer manufacturers, however, seem to have heard our prayers (and curses), and are building tools that make the task of installing framing hardware faster and easier.
We tested the Hitachi NR65AK, Paslode 5250/65S PP, and the Senco SN60MC. We also tested a prototype nailer from Stanley-Bostitch, the N88RH-2MCN. We looked at power and performance while working in tight spots, how well the tools located the nail hole in the hanger, and how each model worked when we were off balance. The fasteners these tools fire are important at inspection time, so we studied those, also. Here's what we found in our field tests.
Finding the Fastener
Making a nailer shoot joist hanger nails looks easy: modify a framing nailer's magazine and shorten the nose and you're in business. The bigger challenge seems to be getting those little nails into those tiny holes. The first hanger nailers were designed to work with special joist hangers with raised nail holes that helped the nailer locate the hole. The system worked pretty well, but forced you to buy a special tool, nails, and hangers. It was expensive and the hanger selection was limited, which meant you'd end up hand –or palm –nailing lots of hangers anyway.
Today's tools work with readily available hardware (that doesn't have raised holes). To accomplish this, manufacturers designed their tools to identify holes either with a probe on the tool or with the nail itself. The probe slides into the hanger hole, allowing the tool to rest there. As you discharge the nail, the probe withdraws and then quickly re-sets itself to locate the next hole. Other tools use the nail as the probe: The nail about to be shot extends beyond the tool's nosepiece and the nail tip locates the hanger hole.
Metal Probe. The Paslode and the Stanley-Bostitch prototype use a metal probe to locate the nail hole. Paslode's probe is highly visible, protruding from the tool's nosepiece. Even in positions where you can't quite see the probe, you can feel it as it slides over the surface of the hanger and slips into position in the hole. This system works extremely well. Even in awkward positions, you can still place nails easily and accurately. The Stanley-Bostitch uses a similar probe, which works well, but the configuration of the N88RH-2MCN makes it a little difficult to see. The engineers at Stanley-Bostitch know this and have plans to correct it on the production tool.
Nail Probe. The Hitachi NR65AK and the Senco SN60MC use the nail tip as the placement probe. The Hitachi is slim and compact; you can see the nail tip easily, even from an awkward position. The tool holds the nail solidly and the system works well. The Senco tool is bulky and it's difficult to see the nail tip when you're in an awkward position. This is a problem, but where the SN60MC really falls down is that it doesn't support the nail the way it should. The nail is loose and moves when you apply pressure, causing the nails to shoot in at an angle. While a little sticker on the tool warns you not to push the tool forward while nailing, this isn't a realistic user expectation. When we tested the tool on the workbench, it fired nails consistently and straight, but when hanging upside down through rafters trying to reach a hanger a foot below our feet we weren't so lucky. Because it's difficult to control the nail's direction, this issue worries me, to say the least.
Every time there's a disaster like an earthquake or hurricane, the call for more survivable building design goes out. Inevitably, the result is more framing hardware. In the old days, carpenters built multi-story buildings with only nails and lumber. Pressure blocking and proper nailing did the trick. Today, every large frame structure gets three truckloads of lumber and one truckload of joist hangers, strap ties, rafter ties, and tie downs. Engineers specify the hardware and specific fasteners for these connectors.