Mastercraft 12V Lithium-ion Auto Hammer

Limited to setting smaller nails and very loud


Mastercraft 12V Lithium-ion Auto Hammer

The Mastercraft 12V Lithium-ion Auto Hammer (054-1257-6) is similar, in concept, to a pneumatic palm nailer. Rather than compressed air, a 12V lithium-ion battery drives a small piston within a sleeve, delivering 3,600 impacts per minute. The tool is activated with a single speed trigger.

The Auto Hammer is about 10" long, and weighs just over 1 3/4 pounds (with battery installed). While it's fairly light, the placement of the trigger forces you to grip the Auto Hammer forward, toward the head. I find that this makes the tool feel off-balance. Also, persons with smaller hands might find the handle bulky. 

There is no conventional 'on/off' switch; rather, the Auto Hammer uses a pressure switch. Press the power switch and the tool engages at maximum power. You have to keep the trigger depressed while running the tool; there is no lock-on feature. As well, if you inadvertently press the power switch while carrying the tool, or if the switch comes into contact with anything on your workbench or in you tool box, it will start up. There is a bright white LED work light just above the trigger that makes it easy to see where you're nailing.

The business end of the Auto Hammer
Trigger is up near the head, putting the hammer somewhat out of balance
The magnetic sleeve is 7/16" wide; which means that, theoretically, you can use nails with a head diameter of up to 7/16". The magnet is not very strong; it will barely hold a 6d nail, and won't hold a 10d or larger nail. I was able to use the Auto Hammer to fully set 6d and smaller nails in softwood, to almost set 7d and 8d nails, but could only partially set 10d and larger nails. I also tried setting nails in hardwood and plywood. You can set smaller 2d to 4d nails in hardwood and 2d to 6d nails in plywood. Don't bother with longer nails.

The weak magnet barely holds a 6D nail
Won't hold (or full sink) 10D or larger nails
One thing you need to be aware of is that the Auto Hammer is incredibly loud. I measured it at 115.4 decibels. Using this tool without adequate hearing protection would be committing aural suicide.

I like the concept of the Auto Hammer; persons who find it difficult, or impossible, to use a hammer could use a tool like this. In it's present configuration you can use it to set small nails in cramped areas where swinging a hammer isn't feasible.
However, for it to be a really useful, Mastercraft needs to do some refinement on the tool. A stronger magnet, possibly a smaller diameter sleeve, proper on/off switch, more power to fully set at least 10d nails, and a lower noise level.

  • 9 7/8" long
  • 12V lithium-ion power source
  • 3,600 IPM (impacts per minute)
  • Magnetic sleeve and head
  • LED work light
  • 1.85 lbs (with battery)
  • 3 year exchange warranty
  • Includes: 1 battery, 30 minute charger, instruction booklet
MODEL #:054-1257-6

Carl Duguay, September 2010
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