I have a Bostitch nail gun (pneumatic) and it has been working fine all day until about 30 minutes ago.

I went to nail in a piece of molding, and when I pulled the trigger I heard air feed into nozzle, but not the normal noise I hear when a nail is actually driven into the wood.

I first checked to make sure I wasn't out of nails and I had a full stack of them.

I then disconnected the gun from the air supply line and took the nozzle off. This is what I found:

enter image description here

Every now and again I get a misfire when it tries to fire two nails at the same time. In these situations, I disassemble the nozzle like I did here and get the nails out. When I took the nozzle apart this time, I noticed that the "hammer" (the thing metal piece that drives the nails in) was not in its correct position.

Usually, the hammer is fully extended, taking up the entire length of the nozzle that you see above. However, in the photo, you see that the hammer is stuck in the "ready to fire" position and will not come out.

I'm not sure if that's the problem (that the hammer is stuck inside the gun), or if something else is going on, but I've spent almost an hour looking at this and am at wit's end.

Any gear gurus out there see what the problem is? Is there a set of things I should be looking for to render a diagnosis?

  • 2
    I see that when tools are not oiled regularly. You need to add a few drops of pneumatic tool oil into the tool where the air hose connects, the air then distributes the oil throughout the tool. The tool should tell you how often to do that.
    – Gunner
    Commented Oct 28, 2012 at 23:10
  • Thanks @Gunner (+1) - so after I apply the drops, I reconnect the hose, and I should be good to go (if it's an oil issue)?
    – bfodder
    Commented Oct 28, 2012 at 23:23
  • Air tool oil is good to have around not only for your air tools, because is is an excellent all-round lubricant for everything around the house and shop. I use the Kleen-Flo stuff. It contains a penetrating solvent, good quality hydrotreated oil, and a zinc-based anti-wear/anti-rust additive, and is cheap! When in the past I might have naively reached for WD-40, that Kleen-Flo Air Tool Oil is now my "go to" stuff.
    – Kaz
    Commented Oct 31, 2012 at 0:00
  • Just on the WD-40 bit, this is relevant: When should I not use WD-40?
    – gregmac
    Commented Dec 4, 2015 at 7:06
  • I agree with user47333 about the correct gauge nails to be used. I unknowingly loaded the gun with 16 ga nails , got two "shots" and it was all done nailing. I put oil into it , thinking this is the problem , to no avail. When I looked at the pkg of nails , it then sunk in. Had to remove the cover , remove the 16 ga nail , loaded it with 18 ga nails , and , it took right off. Sometimes it is just a human error which can be corrected . Thanks to answers on here which brought this to my attention for correction ...
    – user56517
    Commented Jul 18, 2016 at 3:58

4 Answers 4


Oiling your gun on regular intervals is important. In your case, if the pin is stuck, try the following.

Put several drops of oil directly on the pin and slide channel. Remove all nails, reassemble the nose and see if the gun will dry fire against a scrap piece of wood. the gun should fire and leave a dent from the push rod in your wood if it is working.

If the gun still does not fire, then the pin may be damaged or bent. At this point the upper air chamber will have to be removed and the pin assembly removed/replaced. Rebuilding air guns is not real difficult and parts for a Bostich are readily available. You problem may be a worn or damaged O-ring in the compressor section. Rebuild kits for the upper end have got to be replaced often, especially if they have not been oiled regularly of after long periods of storage. Parts are cheap.

Some folks at the tool dept of Lowes or HD could be helpful guiding you. If you have a good lumber yard that sells Bostich tools, they often stock the parts and will be helpful in helping you fix your tool.

In my area, Bostich often have promotion displays at the vendors where they will do maintenance and install rehab kits at no charge with the purchase of a case of nails. Both of my framers, Bostich 88W's, have been rebuild at least 4 times for free during these promotions.

  • Be careful as some of the more recent nailers are oil free.
    – user44444
    Commented Oct 10, 2015 at 17:16

Seems like the allen wrench fittings up top are special sizes, as my Dewalt tool did not have the right measurement to get a tight grip on the heads. I ended up cranking the compressor to about 120 PSI, depressing the head, then ejecting the stuck brad out by pure force of more air. Worked great!


This happened to me. The nails got stuck, and it didn't sound right, so I pulled the safety cover and the driver guide cover. I removed a jammed nail twice. I finally decided to try a sleeve of nails from another package, and it all worked.


Make sure the nails are the proper gauge for the gun. I mistakenly loaded 18 ga nails into a 16 ga gun. It did the same thing you described by trying to shoot two nails at once. When the 16's were loaded, it worked flawlessly.

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