Review By Dean Bielanowski  Fasco Website -



Fasco F21T / H21T GN-40A
Pneumatic Brad Nailer

By Dean Bielanowski

Bookmark and Share

Of all the pneumatic nailers I own, the basic brad nailer gets used the most in the workshop. Gone are the days of hammers and bruised thumbs... there is a tool for everything! In fine woodworking and cabinetry work, and for many general workshop tasks, a brad nailer becomes a very handy tool to have in your toolbox.

The Basics
A brad nailer is at the 'small' end of the range in terms of nail guns in that it fires some of the smallest nails - or commonly called "brad nails". A brad nailer is not generally suitable for fencing, framing, roofing or other heavy duty tasks. It is used to pin items, or as temporary holding clamps in gluing tasks. The brad nail itself is small in diameter, is not terribly strong itself and has a rather small T-shaped head. You can even get headless nails (pins) for use in pin nailers.

If you are looking for a nail gun to do large trim or molding work, baseboards and the like, look at a 15 or 16 gauge finish nailer. If you want to do basic framing, look for a larger frame nailer. For fencing and roof work, look for coil nailers, and for decking or fastening wood to concrete etc, look out for the larger T-nailers.

So as you can see, there is almost a nailer for each type of task. Since woodworkers commonly need to glue things up, make jigs and temporary clamp or pin items together, the brad nailer should almost be the first nailer you buy. Brad nailers typically fire 18 gauge nails.

The Fasco GN-40A Nailer
Ok let's take a good look at this brad nailer model by Fasco. Firstly, the nailer is made in Italy, which makes a bit of a change to many of the chinese/taiwanese import nailers flooding the market in recent years. It has achieved a CE standard rating, which is a quality and safety rating endorsement in Europe.

The package comes shipped in a box (no molded case) simply with the nailer,  instruction manual in English and Italian, and a test certificate saying the product has been tested and has passed Fasco's quality control program.

To get started using the nailer, you will need to supply a compressor or compressed air source, some brad nails, a 3/8" male threaded quick connect air plug (I used a 3/8" to 1/4" adaptor as I couldn't find a 3/8" threaded quick connector in the style I needed locally - this worked perfectly fine) and eye protection.

Begin by screwing in your quick connect fitting into the base of the nailer. Wrapping the threads with plumber's thread sealing tape will help eliminate air loss or leaks. The GN-40A has a minimum working pressure of 60PSI (4 BAR) and a maximum recommended operating pressure of 100 PSI (7 BAR). It is wise to stick to this max limit to prolong tool life and enhance tool safety. Naturally, you will probably need a regulator fitted to your air supply line to regulate air to this pressure. Once that is set up, and we have a full tank of air ready to go, we can load up some nails. A note of caution - Never load up nails, remove nails, clear jams or make any adjustments to the tool with an open air line connected to the tool!

To load up nails, we must first release the magazine cover. This is done via a small spring loaded latch at the bottom, back side of the magazine. Simply push in, and slide the top cover down. Within the magazine is a spring loaded nail feeder which ensures the brads are held to the top of the magazine ready to fire at all times.

The GN-40A uses 18ga brad nails with the following listed specification:

  • Head: 0.086" (2.20mm) 

  • Wire: 0.039" - 0.050" (1.00 x 1.27mm)

  • Length: 5/8" to 1 9/16" (15mm to 40mm)

According to the Fasco America website, specific item numbered nails that can be used with this brad nailer are:

  • Senco AY - 18 gauge brads

  • Senco AX - 18 gauge brads

  • DuoFast 4400 Series

Given that Senco and DuoFast nails are available very widely, there should be no problem finding a local supply of nails to use with this gun. Other generic brad nails may also be used if they closely match the stated specifications listed above. We can load as many as 105 brad nails into the magazine. This is about an average figure for most brad nailers of this size. Brad nails are often sold in lots of 1000, 3000 or 5000, so even if you have to mail-order them in, there shouldn't be a problem, as long as you order extras well before your current box starts running low.

Fasco America's website state they will also ship "Any Tool, Any Fastener, Any Quantity, Anywhere" so you can order supplies direct from them if necessary.

Ensure the spring loaded feeder sits below the last nail in the stack so it is pushing up on the nails from the bottom. Slide the nails as far forward as possible, naturally, with the "pointy, sharp ends" facing toward the front of the nail gun. I've seen some DIY'ers get this wrong!

A nice feature on the GN-40A bradder that is missing from my other brad nailers is a small nail magazine viewing window toward the top of the magazine. With nails loaded, you get full view of the nail stack, so you can visually see if you are running low on nails. Once the number of nails falls to a low level, a red indicator starts to appear in this window. This is an effective way of warning the user that it is time to load up some more ammunition and means you do not have to strain your eyes peering into the window to see how many nails remain. This neat little system will avoid the problem of "firing blanks" and unnecessary wood filling work later on. A nice added touch.

We are almost ready to go... Before you hook up your air supply however, take a moment to check the no-mar rubber tip is attached to the safety catch on the head of the tool. If it isn't insitu when you receive the tool, the no-mar tip is attached on a holder on the lower reverse side of the nail magazine. Remove from there and apply it to the safety catch before you begin work. This will reduce the incidence of marking/denting your timber from the head of the safety catch when working with very soft material.  

Ready to Nail!
Ensure your air supply is regulated to between 70 and 100 PSI before you begin. Put on your safety glasses and ear protection before you begin.

Firstly, it is important to know that whenever you are hooked up to an open/flowing air supply, the gun will fire when both the safety release and trigger are depressed together. This is not a toy to try and knock down cola cans in the back yard or worksite (ala that "Happy Gilmore" movie). Nail guns are dangerous tools. Have respect for them!

In saying the above, the tool is able to be used as a bump fire device, although I do not recommend it - it increases the risk of injury. Unless you have a need to rapidly fire brad nails without a high degree of placement accuracy, use the nail gun in the following manner. Firstly, decide where you want to shoot the brad nail. Place the tip of the nail gun on that mark, pushing it into the wood to depress the safety release, then squeeze the trigger for a brief moment to fire a nail. Do not hold the trigger in as there is a chance of unwanted additional firing if you knock/depress the safety release unintentionally.

The same process is repeated for further nailing. It's very simple to use. We performed a number of tests using hardwood and softwoods to see how well the GN-40A could drive drives into these materials.

We tested using some scraps of pine to perform multiple, repeated nail gun use in quick firing succession, as well as general shop use with a variety of softwoods for trim attachment, moldings, as temporary clamps for jig making... the list goes on. There is a photo in the right column showing a close-up shot of the results of our repeated firing test. Given that the GN-40A (like most other brad nailers) has no mechanical adjustment feature for driving depth on the tool itself, the depth can be loosely (and often inaccurately) controlled by air supply pressure. It's not really ideal, so it is critical that the design and function of the brad nail gun allows a consistent, even nail driving depth in all types of softwoods and hardwoods within the specified recommended operating pressures.

With softwoods, we had excellent success with nails being driven roughly 1/32" to 1/16" below the surface consistently, even when we bump fired nails rapidly we achieved the same consistent result. With the grain, or cross the grain, the results were all pretty similar. Points scored in this area. The advantage of a brad nailer over heavier gauge nailers is that the nail hole is much smaller, easier to fill and, ultimately, less noticeable in the end product. If you are going to be firing nails very rapidly, ensure your air supply hose is of sufficient diameter to keep up. Brad nail guns (and air nailers in general) use very little air compared to pneumatic tools like air sanders, air grinders or sprayers. As a result, most nail guns can be run off small compressors, even the 'pancake' variety, although these will cycle more often due to the smaller tank.

We performed similar repetitive tests on a variety of hardwoods including maple, oak, merbau and Ipe. Driving into hardwoods is a tougher task for the nail gun. I have a Chinese made brad nailer I bought years ago at a sale, and while it works fine for softwoods, it can give inconsistent results in more dense hardwoods, often not burying the nail head all the way into the wood, particularly close grained woods that offer increased resistance. While you can use a nail punch to complete the job, it is not ideal from a time perspective, and you risk spitting the wood from repeated blows with a nail punch.

I was hoping the Fasco GN-40A would solve those problems for me. After the first test run, we repeatedly fired nails into dense Ipe hardwood across the grain. We fired 10 nails in succession. 9 out of the 10 nails were driven to the same depth as in our softwood tests (roughly 1/32" to 1/16" below the surface). The tenth nail was not driven all the way in, remaining slightly proud of the surface. I suspected my narrow coil hose may have been the culprit in this case, so I switched to a larger diameter non-coiled hose and repeated the test. It came up trumps second time around with 10 out of 10 nails driven consistently below the surface. I repeated a third time and again a perfect result. I switched back to a softwood and repeated again with the same end result. I would conclude that during the first rapid bump fire test with the narrow coil air hose in use, the small diameter was restricting air supply in continuous rapid firing tasks. No fault of the nail gun itself, but interesting all the same. I guess the moral of the story... if you are going to rapid fire, use a supply line that can handle it!

General Use, Features and Findings
Firstly, the rubber overmold grip on the handle is a definite asset, although all nail guns I have come across so far have this. It prevents slipping, however, this is not such a problem with a brad nail gun that has little recoil. On the subject of recoil, very little was experienced in both softwood and hardwood driving tasks. The GN-40A is comfortable to use in this regard. Given its light weight of 2.73lbs (1.24kg), you can use it for extended periods of time, even for overhead work, and not need to book into a chiropractor the day after.

In terms of user comfort, perhaps what is missing is a rubber overmold on the trigger. Some may say its not needed, and functionality-wise, it really isn't, but I have been spoilt by the rubber molded trigger on the Senco 41XP Finish Nailer which adds additional user comfort. We had no problems with the trigger on the GN-40A despite this - perhaps a consideration for future versions.

The safety catch is sufficiently small to get into tight corners, such as when toe-nailing dado joint shelves. While it is not as effective as some of the narrow pin-type safety release mechanisms available, it was still able to drive the nail slightly below the surface in most cases. The GN-40A's safety release design does allow for the inclusion of the no-mar rubber tip however.

In use, we could not detect any signs of air leaks in the tool. The exhaust port on the back of the head can be rotated 90 degrees left and right from its upright position, however, this requires use of a hex-head/allen key tool. In most cases, there will be little need to rotate it from its upright position, as long as the exhausted air is not being blasted directly toward you or others in close vicinity. A rubber gasket is used to improve sealing between the body and cap of the tool. This provides added re-assurance and durability.

Speaking of durability, a nice feature of the GN-40A is that it uses a reversible bumper for extended life. If the bumper wears out through extended use over time, you can simply reverse it instead of having to send it to the repair shop for replacement. We don't expect to have to reverse the bumper any time soon.

Another excellent feature of the GN-40A (patent pending) is the "quick clear device". With many other types of brad nailers, if you suffer a nail jam, you need to pull out the tool box, loosen several nuts or fittings to disassemble the safety catch before you can get access to the jammed nail to remove it. With the GN-40A, a rear latch between the inside edge of the nail magazine and the handle can be used to draw the entire nail magazine assembly downward, exposing the bumper firing channel and the jammed nail. This can be done within seconds (once air hose has been disconnected for safety) and the jammed nail can be removed easily without tools! This is certainly going to save a lot of time and frustration if a nail jam does occur. I must admit that I rarely do get a nail jam with my brad nailers, even the cheap Chinese one. I have not had a jam with the GN-40A as yet either. I expect this feature of being able to remove a jammed nail almost effortlessly to be a smile generator rather than a frown generator if and when a nail jam occurs in the future.

The brad nailer is quite a "simple" tool compared to others we use in our woodworking endeavors. Despite this, Fasco has come up with some very user-friendly additions and improvements to the basic brad nailer that place it higher up in the pecking order of "bradders". Features like the nail magazine viewing window and quick clear nail jam system are well considering before you make your first, or next brad nailer purchase.

On the whole, the results we achieved were very encouraging, with consistency being the key element.

Check out the Fasco America website for more information about this item, other Fasco items and how and where they can be purchased -

*Note that if purchased within the USA, the tool model number is actually F21T GN-40A and is blue in color, rather than the red H21T model shown here. Feature-wise, both are identical. The nail gun is sold through Fasco's distributors - contact them for details of a local distributor. Prices can vary but the nail gun usually runs about US$169.00 (price estimate as at 10/7/2004).

Fasco GN-40A Photos
All photos copyright Use without prior written permission prohibited

The H21T GN-40A Fasco Brad Nailer

Brad Nails from 15mm to 40mm can be used in this gun.

Ergonomic lever releases the magazine clip to load up nails. Because the entire magazine assembly has no welded parts, it is easy to fully disassemble if needed.

Loading up some 40mm brad nails...

Note the "running track" shaped window which lets you see when your nail supply is running low.

With my thumb pressing on the rear latch, I can implement the "Quick Clear" feature, pulling the enture magazine down away from the firing head. This allows you to clear nail jams very quickly without the use of additional tools. Very cool!

You will need a 3/8" male fitting to use the GN-40A. Here I have used a 3/8" to 1/4" adaptor fitting, and this worked perfectly fine. Seal threads with plumber's thread sealing tape.

The no-mar rubber tip installed.

Good consistent firing depth in softwood. Nails are buried just
below the surface evenly, even
when bump-fired.

We fired into this very dense piece of Ipe decking wood and achieved the same consistent result. A good test of the strength of the gun.

There are plenty of uses for a brad nailer in the workshop. Here we are pinning to clamp a glue-up.

Here we are making a smaller panel cutting jig for the table saw.

Toe-nailing dado seated shelves is a popular use for a brad nailer, and this technique adds some strength the the joint.

Information contained on this page is copyrighted to
Reproduction in any form prohibited with express prior written permission. Copyright 2004