Direct fastening technology is a system in which a hardened nail or stud is driven into steel, concrete, or masonry using a power-actuated tool in which the internal piston drives the fastener into the base material with a driving energy. 

Common fastening techniques include drilling and anchoring, screw fixing, welding, clamping and bolting. But for many applications involving fastening to concrete and steel, using nails as part of a direct fastening system (made up of dedicated tools and nails) can help you save time and money by providing the following benefits:

• up to 5 times faster installation so you can save time, free up resources and meet project deadlines
• poential cost savings through reduced labor cost
  
• safer installation with tested and approved systems. Direct fastening is also virtually dust free, lower noise and lower vibration
• simpler workflows thanks to reduced effort, cordless technologies, higher tolerance of ambient conditions and wide application coverage

DX, BX and GX refer to Hilti direct fastening tool types.

DX tools are powder actuated tools. They are driven by powder cartridges and are best for applications which require higher energy levels. Use them for jobs like fastening to very tough concrete or steel during decking or flooring jobs, fastening wood frames or installing ceiling hangers.

BX tools are battery powered. They are best for light duty applications with the flexibility of cordless. Use the for jobs like laying down hundreds of metres of drywall track, installing electrical fastenings, bottom plate fixing to very tough concrete, or flooring jobs on steel.

GX tools are powered by gas cans. They are best for light duty applications with a single energy source. As with BX tools, you can use them for applications like laying down hundreds of metres of drywall track, installing electrical fastenings, bottom plate fixing to very tough concrete, or flooring jobs on steel.

Not all projects have the same requirements or budget. We have color-coded our nails to help you find the right one according to your performance and pricing requirements. 

• Grey represents Standard solutions with Hilti quality at an economical price.
• Black is for Premium performance for a wide range of applications, with high productivity through Hilti system solutions, versatility and reliability.
• Red stands for Ultimate performance for demanding applications, with the highest overall productivity and safety benefits, the highest reliability in tough conditions, complemented by world-class engineering and software support.

A nail penetrating concrete needs to create a hole for the shank by crushing and compacting the concrete. It also needs to withstand hitting hard aggregates as it finds its way into the concrete matrix. The resulting holding value achieved by the nail is directly linked to its embedment depth.

Penetrability and compactability,  or a nail's ability to penetrate and compact the concrete, are strongly influenced by three nail design features: tip shape (ballistic, stepped shank, long conical and cut), nail geometry (length and diameter) and nail hardness. A harder nail is easier to drive into tougher concrete. However, if the nail is too hard, it can break instead of bending when it hits a hard aggregate in the concrete.

The type of nail you use for fastening to concrete can depend on the hardness of the concrete. At Hilti, we distinguish between three concrete types:

Soft (S)

• Low compressive strength (e.g. 2-5 ksi)
  
• Small to medium-size aggregates; e.g. soft limestone
• Example: lightweight concrete

Tough (T)

• Medium to high compressive strength (e.g. 5-7 ksi)
• Medium-size aggregate; e.g. pit gravel
• Example: normal-weight concrete

Very tough (V)

• High compressive strength (e.g. ≤ 7 ksi)
• High proportion of large aggregates, mainly hard; e.g. quartz, granite
• Example: high-performance concrete, very old concrete

For applications involving fastening to steel such as metal decking, nail performance on the jobsite can be influence by factors such as:

• grade and thickness of the steel being fastened 
• base material (e.g. structrual steel or bar joist). Note that you may also need a range of different nail types for your project if you are working with steel of different thickness steel. Also, because there are wide variations in supporting base material thickness, it's essential to do on-site test installation. If you have any problems, contact us.
• load requirements
• embedment depth

This usually means the nail you have chosen is too short, or you are using too much driving power. Try using a longer nail, or reducing the power setting.

If your nails keep bending it could be that the surface is too hard. Try using a shorter nail, pre-drill using DX-Kwik, or try a stepped shank nail X-U 15. Alternately try more power by changing the cartridge.

All of our Hilti direct fastening tools are equipped with these safety features to help prevent accidents on the jobsite:

• Drop-firing safety - prevents the tool from firing if dropped
• Trigger safety - the cartridge cannot be fired by only pulling the trigger
• Contact pressure safety - the tool can only be fired when fully pressed against a surface
• Unintentional firing safety - prevents "bump-firing"

Last but not least our tools follow the piston principle, ensuring that the energy from the propellant in the cartridge is transferred to a piston rather than to the fastener, reducing the risk of through penetrations.