SKIL 12-Volt Auto Hammer

By ralph mroz on Remodeling, Skil, Tool Reviews

SKIL 12-Volt Auto Hammer

The SKIL 12-Volt Auto Hammer (Model AH6552A-10) was recently reintroduced, this time with a brushless motor.  Some years ago there were several auto hammers on the market, but at the time they weren’t well regarded.  This was due in part to their lack of power and in part because people were looking at them as replacements for regular hammers (which they are not).  The new SKIL 12-Volt Auto Hammer, which as far as I can tell is the only auto hammer currently being sold, overcomes the first objection with a brushless motor (and probably other redesigned elements).  The second misconception I’ll address below.

A Get-Out-Of-Jail Tool

We’ve all been there.  You need to nail something – a bracket, hanger, a piece of wood, whatever – and there’s simply no room to swing a hammer to connect with the nail.  Trying to nail between 16-on-center joists is a classic example, but we’ve all run into the problem elsewhere too.  Remodelers probably run into this issue more than new construction builders because they are forced to interface with the structures and spaces of existing construction.  But everyone has this issue sometimes.

In these cases you really have three alternatives.  Try to toenail A to B, which doesn’t always work.  Try to use or re-purpose a bracket of some sort – which isn’t always possible.  Finally, you can call the help line at 1-800-RUBE-GOLDBERG (I’m not ashamed to say that I’ve used this option many times over the years!)

Or, in many cases, you may be able to use an auto hammer.  Now, the SKIL 12-Volt Auto Hammer is not a replacement for a hammer.  It’s the nailing equivalent of a right-angle adapter for an impact driver.  It can be your get-out-of-jail card; it can get you out of a hard place by getting you into a tight space.

Auto Hammer vs. Palm Nailer

“That’s what a palm nailer is for,” you might say.  Well, true enough.  Except that virtually all palm nailers are pneumatic.  With them you’re forced to drag out the air compressor and string the hose through your jobsite, all of which takes time, to simply sink a few nails.  Not to mention the safety hazards of a pressurized hose, and indeed any hoses at all on a jobsite.  Also, if you’re working in an occupied space you risk the stiff and pressurized hose knocking over Mrs. McGillicutty’s antique vase. It’s much easier and safer to just grab an auto hammer – which takes up FAR less space in the truck than a compressor — and get the task done.

What about battery-operated palm nailers?  Well, there aren’t many on the market, and they tend to be bulky.  The SKIL 12-Volt Auto Hammer can get into tighter spaces and is less expensive.  More functional and costs less – that’s a win-win, especially for a tool that you seldom use (but boy when you need it, it’s a God-send).

Features and Specs:

  • COMPACT SIZE – The digital brushless motor delivers compact, lightweight
  • 3-POSITION ADJUSTABLE HEAD – Switch between 0, 45, or 90 degrees
  • MAGNETIC COLLET – Holds nails (up to 3.5 in. long) in place for one-handed use
  • LONGER RUN TIME AND BATTERY LIFE – PWR CORE 12 lithium-ion battery technology wraps each cell with cooling
  • CHARGES IN 5 MINUTES – PWR JUMP charges the battery up to 25% in 5 minutes, or 100% battery in 45 minutes.
  • POWER ON THE GO – Charge mobile devices whenever, wherever with USB ports built into the battery.


  • Adjustable head angle (degree): 0°/45°/90°
  • After-glow: Yes
  • Drive Capacity (inch): Up to 3.5″ (2d-16d)
  • Impact rate (ipm): 4200
  • LED light: Yes
  • Magnetic sleeve: Yes
  • Tool Length (inch): 9.22
  • Tool Weight (pound): 1.94
  • ½-inch piston
  • Trigger lock-out switch

Using the SKIL 12-Volt Auto Hammer

The original auto hammers of years ago were usually spec’ed for 10d nails, but the SKIL 12-Volt Auto Hammer is designed to drive 16d sinkers.  I used a securely held 4×4 PT as a test medium.  Sure enough the SKIL 12-Volt Auto Hammer – with its head set to 90 degrees (the most common configuration I figured) – drove nails up to 16d nails (both sinkers and the larger brite common ones) predictably.  16d nails took about six seconds to drive.  Of course, smaller nails went in more easily and quickly.  Now, this was an old, knarly 4×4 that’s been hanging around for a while; while driving 16d nails, if I hit a really hard section of it the auto hammer wasn’t powerful enough to keep driving.  However, there was no such problem with smaller nails nor in driving 16d nails into regular KD stock (which is what you’d probably be nailing into).

Laboratory Conditions

I used a secured 4×4 clamped to a bench for a test medium because it gave me predictable “laboratory” conditions for a baseline.  Much of the time, however, you’ll be using the SKIL 12-Volt Auto Hammer out-of-position, while in some unpredictable position, and its performance could be degraded.  That’s because, the laws of physics being what they are, you need to brace the back of the auto hammer head with your hand.   Otherwise, once the nail meets reasonable resistance the piston will simply bounce off of it.  Thus, this is generally (not always) a two-handed tool.  You may well still be able to drive the nail but it may take longer than under ideal conditions.

But: my out-of position nailing consisted mostly of driving 16d nails into bracing pieces between 16 OC joists – working overhead of course, and standing on a stool.  So long as I could get a reasonable amount of pressure behind the auto hammer head I had no problem at all – the nails went right in.  So actually there was no performance degradation is this common out-of-position posture – that was a pleasant surprise!

Real World Conditions

No matter what position you are driving from, it’ll be a lot easier if you can get the first millimeter or two of the nail started in the wood – sometimes even hand pressure can do that.

The piston of the SKIL 12-Volt Auto Hammer is ½-inch in diameter and in the piston’s rest position sits back ¼-inch from the far end of the sleeve.  From the piston end to the rear of the head is about 4.5 inches, and to the back of a bracing hand is about six inches (see photo below).  That means that you’ll need a clearance of at least six inches plus the length of your nail to use this tool; for working between 16 OC studs or joists that’s not a problem.

Bottom Line

The only problem I had in using the SKIL 12-Volt Auto Hammer was that the head would sometimes pop into the 45-degree position when I was hammering in the 90-degree position.  That’s aggravating but really only costs a few seconds while the head is re-positioned.

The SKIL 12-Volt Auto Hammer fulfills what I regard as its promise.  It’s a tool to get you out of a jam in which you need to drive a nail but can’t swing a hammer.  Rather than use the side of a hammer and make little rat-tat-tat feeble strikes on the nail (as we’ve all done, with frustratingly meager results), this tool gets the job done more quickly and easily.  It’s definitely worth having in your bag of tricks now, and if SKIL ever comes out with an 18 or 20-volt model, it will have plenty more performance margin.

This is not an everyday tool, but one that any Type 2 or Type 3 trades person will be glad they have when they need it.  It’s currently $119 at Lowes, including battery and charger.

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About the author

ralph mroz

Ralph Mroz grew up in an extended family of tradesmen, and worked at the trades summers and weekends through school. He put those skills to good use in renovating the five houses he and his wife have owned. Even while working in the white-collar and law enforcement worlds, he's always had one foot in the construction trades.

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