MRO Today - Screwguns: Hard drivers

Screwguns: Hard drivers
You could think of them as drills on steroids. The new generation of screwdrivers have leaner bodies and greater brawn and endurance when compared with their predecessors.

by Clair D. Urbain

Screwguns are built to drive screws in rapid succession into metal or wood studs as well as hang drywall or fasten plumbing, conduit or a myriad of other components.

Its a demanding job, and workers know how to push these tools to their limits, and beyond.

"This is one tool that is truly consumed," says Chris Keffer, DeWalt electric drill and fastening tool product manager. "From the tip of the driver to the end of the cord, users work these tools to death."

Thats why durability ranks at the top of the list when it comes to driver design, followed by user comfort. Power tool manufacturers are pushing the envelope ever further to help users get more life and comfort from the tool.

"In our research, we have found that pros look for speed and durability," says Mike Whitman, manager of product development at Porter-Cable.

Put it in the palm of your hand
Screwgun design has evolved to allow users to better "palm" the tool while using it, says Keffer.

"Workers want these tools to be lighter, feel good in the hand, be quieter, blow less dust and have the power to do the job. The backside of the tools are now narrower and built with a lip that makes it fit more naturally in the crotch between your thumb and forefinger," he says.

The rubber trigger works with a gentle squeeze of two fingers in a natural position.

While the new generation of tools is a bit lighter, greater inroads are being made in tool balance.

"When you compare the older DeWalt style of screwgun with the newer style, youll see that the new models are only 1.25 ounches lighter. But if you pick them up, the newer model feels lighter. Its because of the way the tool balances in your hand," Keffer says.

For better grip and control, the tool manufacturers are adding rubber strips on the tools to cushion workers' hands and improve gripping ability. For example, on Milwaukees new screwgun line, the tactile rubber grip is molded into the tool.

"The two-step molding process bonds the two components to assure it holds up under tough conditions," says Tom Pope, driver/drill product manager at Milwaukee Electric Tool Corporation.

The new drivers take controls to new levels of comfort.

"The two-finger squeeze triggers fit nicely in the hand. The reversible feature makes backing out screws a snap and, for high-production applications, users can lock on the trigger for continuous driving," says Pope.

Milwaukees new models put the switch-lock button in a protected dimple for easy access, yet makes it hard to accidentally activate the trigger lock.

Sound effects
Tool makers have also made great inroads in quieting the tools. In the past, clutch designs did not release cleanly and created a ratcheting noise.

Today, the tools use snap-action clutches that keep the power pushing through the tool until the screw is almost driven home. Result: a quieter tool.

"Even though clutches are different in tools, in general todays clutches stay engaged through the drilling cycle. When the screw bottoms out, it releases, not ratchets, which makes the tool quieter and smoother to operate," says Whitman.

More power
New screwgun models sport more power than past units.

"Its a tough balancing act. The user looks to amp ratings as a gauge for power and they want more power to do the job faster, but the tradeoff is weight. Users dont want a heavy tool," says Keffer.

For example, DeWalt and Milwaukee offer 6.5-amp drivers that offer as high as 4,000-rpm no-load speeds. The tools weigh about 3 pounds.

Although workers want a one-size-does-all tool, you can better match the tools power to the job by selecting the driver speed for the application.

Everyone wants speed, but the weight tradeoff for the torque needed in heavier applications would mean the tools would be too heavy. So engineers changed gear ratios in tools to better balance speed with the torque needed to get the job completed.

If you hang drywall or do light framing, 4,000-rpm models can handle the job.

If you are deckbuilding, doing 14- to 20-gauge stud framing and drywalling, you may need to go to a 2,500-rpm tool to get the power to drive home screws successfully.

If you are driving TEKS screws, metal-to-metal roofing or thick structural steel fastening or 12- to 20-gauge steel framing, you may need a driver with a speed as low as 1,000 rpm to get the job done.

Its all in the nose
Depending on the model, all three tool manufacturers offer a variety of driver noses. If your driving needs vary, consider a model with an adjustable clutch that allows you to match the driving power to the job at hand. Still others feature replaceable clutches for in-field repair.

Milwaukees new bit control system helps minimize wobble and runout, speeding screw driving. Its pop-off nosepiece simply twists off so the driver can be used in framing and drywalling jobs.

DeWalt models allow users to take advantage of the "set and forget" nosepiece for metal stud framing. Here, workers can remove the nosepiece for stud work, then replace it for drywall work without having to reset the depth setting.

Selected models of Porter-Cables drivers can be fitted with a nosepiece adapter that allows their use with Quik Drive fastening systems.