Wheeler F.A.T. Wrenches: Accurate Torque for Your Gunsmithing Needs

The original Wheeler Engineering black and yellow F.A.T. Wrenches have been a staple on the workbenches of gunsmiths and tinkerers alike. The hand-held torque wrench’s popularity is due to its ease of use, firearm-focused torque ranges, and one-handed operation. Within the last few years, Wheeler has revitalized the F.A.T. Wrench in a major way with new F.A.T. tools. Coinciding with the release of these new tools was a refreshed brand identity. Gone are the bumblebee colors; they are replaced by black and dark tan. The name is simplified to Wheeler and cleverly set in a box wrench with a “W” sitting in the wrench opening.

F.A.T. Wrench

F.A.T. is an acronym for Firearm Accurizing Torque. The F.A.T. Wrench is a hand-driven, click/clutch-style torque wrench. Torque value is set by lifting and rotating the cap. A sliding indicator on the side of the body points to the torque value. Torque values range from 10-inch pounds to 65-inch pounds. The updated F.A.T Wrench retains the same height and width as the original, but the body is slimmer and sculpted with two flat spots. The result is a contoured grip that allows for a stronger hold while turning. Other welcome improvements include broader use of the rubber overmold with a scale-like texture. Both lead to better traction when wrenching.

When the wrench reaches the set torque value, there’s no mistaking the abrupt break with a distinctive click. The advantage of a click/clutch mechanism is that you can’t torque beyond the set value. If you turn the wrench, it will just click again. With a “click-only” wrench, it can apply torque beyond the click. Since spring tension provides the torque force, you’ll want to return the torque setting to its lowest value after use. Keeping the spring under tension can put the system out of calibration. The torque wrench ships with a hardcase box and 10 commonly used bits.

Digital F.A.T. Wrench 

The Digital F.A.T. Wrench has been in the lineup for almost a decade. Like all the other Wheeler products, it received a facelift, but the core functionality and interface remain the same. The digital interface is operated by 5 buttons. Torque value is set with the plus and minus buttons. The “U” button changes unit of measurement, lbs.-in., Nm, kg-cm. Pressing the “M” alternates Live Mode and Peak Mode. The Live Mode is a live reading of the amount of torque you are applying. In Peak Mode, the wrench only shows the highest pressure you applied. The torque range is from 5 to 100 inch-pounds, and it offers incremental changes down to the ounce.

Instead of a click when the set torque is reached, you’ll hear a series of beeps when you’re getting close to the setting. A long single beep sounds when you hit the preset number. There is no click, and it’s possible to apply more torque, but you would need to abandon common sense to keep going. Like the analog wrench, it ships with a hard case and 10 commonly used bits.

If I were forced to make a choice between the click or digital wrenches, I’d relegate the digital version to my workbench and the analog to my range bag. I don’t want to worry about batteries in the field. My only complaint about the Digital F.A.T. Wrench is that the numbers change too slowly when holding down the plus or minus button. It takes 1 second to change 1 pound. It’s really noticeable when moving from 5-inch pounds (the default startup setting) to 65 pounds, the torque value of my precision rifle’s action screw.

100-Piece Professional F.A.T. Wrench Screwdriver Set

If you work on firearms frequently, the 100-Piece Professional F.A.T. Wrench Screwdriver Set is the way to go. You’ll have all the bits you need in one case. The bits include 28 flat heads, 5 Philips, 13 Torx, 13 metric hex, 13 standard hex, 15 nut drivers, 3 squares, and 5 specialty bits for Leupold scope bases. Interestingly, the 7 largest Torx bits have a hole in the center. These are designed for tamper-resistant Torx security screws. These bits work with regular Torx heads too.

A F.A.T. Wrench, a regular driver and an extension are part of the kit too. The ¼-inch ends are all magnetized, so your bits won’t fall out. The rubber overmold from the F.A.T. Wrench is found on the driver’s handle.

What I like about the kit is that it’s one of the most extensive gunsmithing screwdriver sets I’ve seen. The bits are phosphate-coated to prevent rust and corrosion. The flathead bits are hollow ground, meaning that the sides have a slight concave curve which allows the screw to reach the bottom of the slot and fills the slot more precisely. The benefit is that it is much less likely to slip and damage a screw head than a flat head with vertical sides. Other standouts are the metric and standard nut drivers, and .05-inch and 1.5 mm hex keys.

All parts come packed in a nice hard case that utilizes hinged latches that will not wear out over time. A map of the bits is on full display when the case is opened, so you won’t have to guess which bit goes where.

The set is currently only available with the click-type F.A.T. Wrench.

F.A.T. Wrench Auto Torque

If you frequently reach for a torque wrench, you’ll greatly appreciate the drill-like F.A.T. Wrench Auto Torque. According to Wheeler, this is the first battery-operated screwdriver with an integrated torque limiter. It’s powered by a removable 12v lithium-ion battery that is charged with a USB-C compatible charger. The battery has a 2-hour continuous run time. A battery level indicator sits on the side of the battery and can be checked anytime with the press of a button.

Adjusting the torque setting is intuitive; press the plus button for more torque and the minus for less. When either button is held for a duration, the numbers speedily jog along, allowing you to make large adjustments quickly. I wish the Digital F.A.T. Wrench was this speedy. The large LCD display shows the torque value. Torque range is 10-to-65-inch pounds with .1-inch pound increment changes. The MAX button above the LCD screen switches to maximum power to remove stubborn screws.

Working the F.A.T. Wrench Auto Torque showed me that the engineers have worked with small screws on firearms a lot. The trigger on the 200 RPM variable speed motor allows you to feather the speed. This is especially beneficial when screwing small screws like those found on red dots. The motor turns slow enough allowing you to ease the screw throughout its travel. You’re less likely to strip threads this way. Pressing the trigger automatically activates 4 bright LEDs washing the working area with white light.

My first test with the screwdriver was setting the torque to 10-inch pounds and installing a red dot. I was curious how heavy- or light-handed the force would be on the small screws. I eased the screw in and when it reached the torque setting, the motor softly disengaged. I expected it to be more abrupt and jerky. I then put it to work on scope ring and mounting screws. The numbers flew by as the torque value went from 15-inch pounds to 65-inch pounds. Each time that I reached the torque setting, the screwdriver disengaged softly. This screwdriver is so cool, that I looked for more screws to tighten.

The F.A.T. Wrench Auto Torque includes a hardshell case with 15 popular bits. This includes a flat head, a Phillips, a ½-inch socket, 6 standard hex, 4 Torx, an extension, and a ¼-inch socket adapter.

F.A.T. Stix Preset Torque Wrench Set 

The F.A.T. Wrenches and F.A.T. Wrench Auto Torque are great tools, but they are bulky. The F.A.T. Stix are travel-friendly and take up very little space in a range bag or backpack. They are also a click-type torque limiter and come in 5 pre-set torque limits. They include a 15-, 25-, 35-, 45-, and 65-inch pound limiters. The 15 is perfect for many scope ring screws, the 25 to 45 work well on scope mounts, and the 65 is common for centerfire rifle action screws. To torque a screw, attach the T-handle and bit to the limiter and twist away. When the limiter hits its pre-set torque it clicks.

Like other wrenches, you get a series of ¼-inch drive bits. These include 4 Torx, 1 Phillips. 1 flat head, 6 hex, an extension, 1/2-inch socket, and ¼-inch hex adapter. The kit comes in a hard foam, low-profile case with a form-fitting polymer tray. Each tool has its spot to prevent rattling. This one pack that can get you out of most loose screw emergencies in the field.

XL F.A.T. Wrench

There are several rifle components where the regular F.A.T. Wrench is woefully underpowered. Enter the XL F.A.T. Wrench. The XL F.A.T Wrench is designed to handle components that require foot-pound torques. AR barrel nuts, barrels, castle nuts, and some muzzle devices are examples of this. Its ½-inch drive ratcheting head has a range from 10-to-150-foot pounds or 13.6 to 203.6 Newton meters. Both scales are found printed on the handle. Also, on the handle near the head, are torque values for the barrel nut, castle nut, and muzzle device. Generally, an AR barrel nut is torqued to around 40-to 80-foot pounds and a castle nut 40-foot pounds. My precision rifle barrel is torqued to 80-foot pounds.

The XL F.A.T. Wrench is a click-type torque wrench. To use it, the loosen the nut on the bottom, then rotate the handle until the mark lines up with your desired torque setting. Once it’s set, tighten the nut. When torquing with a crowfoot wrench, you want to the open-end to be at a 90-degree to the handle. In the case of the Wheeler’s double-headed crowfoot, you will want it to form a “T”. Once you reach the torque limit, the head will rock and click. When you are done with the wrench, remember to set it to its lowest setting.

The quality of the XL F.A.T. Wrench is on par with the other contemporary torque wrenches I keep in my toolbox. The difference is that the numbers on the XL F.A.T. Wrench are much easier to read. For the average user, it will provide a lifetime of use.

The XL F.A.T. Wrench is available in several sets. My favorite is the Ultimate AR-15 Armorer's Kit for $439.99. The 28-piece kit has all the tools I need to build an AR-15 and AR-10 from parts. Of particular importance are the upper receiver action rod, upper pic rail vise block, and accurizing kit. The upper receiver action rod is the ideal tool for barrel installation. It locks the barrel and receiver together assuring gas port alignment. The upper pic rail vise block is made of machined aluminum and accommodates both AR-15 and AR-10 upper receivers. The accurizing kit trues the face of the upper receiver for a square barrel alignment.

The kit includes 5 dual-headed crowfoot wrenches that handle 12 functions including castle nuts, buffer tubes, muzzle devices, and a variety of barrel nuts. Smaller, but essential tools include an AR-15 pivot and roll pin installation tool, magwell vise block, armorer’s bench block, and several punches.

If the Armorer’s Kit feels like overkill for your needs, the XL F.A.T. Wrench is available in a smaller kit with the Mil-spec Crowfoot Set and Complete Crowfoot Set. The Mil-spec set contains 3 dual-ended crowfoot wrenches which have 8 functions. The set handles AR-15 and AR-10 barrel nuts, buffer tube extensions, ¾-inch muzzle devices, Mil-spec castle nuts, and low-profile castle nuts. The complete set adds two AR-15/AR10 barrel nut wrenches.

Calibration

Each F.A.T. Wrench is individually tested and ships with a calibration certificate. The calibration includes testing a low, middle, and high torque range. The certificate includes a lower and upper limit range that it must fall into to pass the test. All of the actual readings were within these limits with most within 1 to 2 pounds of the torque setting. Considering we’re working with firearms and not the space shuttle, the F.A.T. Wrenches are plenty accurate for gunsmithing.