Things You'll Need
The Craftsman staple gun provides a competent, manually operated means for applying stapes to surfaces. There are a number of reasons why a Craftsman staple gun will suddenly cease to function optimally. You can troubleshoot the Craftsman staple gun to identify the problem plaguing it. No special tools are required, although wearing gloves and protective eyewear to protect yourself from an inadvertently fired staple during the troubleshooting is sound advice.
Erratically firing staples could be the result of wrong ones having been inserted into the Craftsman, so first pull the two latches at the bottom of the Craftsman staple gun to release the loading chamber. Pull the chamber out. Remove a staple and measure the length of the points with a ruler. If the length does not match the number written on the Craftsman's side, the staples being used are incorrect and causing the staple gun to not work correctly. Remove the staples and replace them with the correct types before closing the chamber.
Staples not exiting the Craftsman when the trigger is depressed could be the result of a stuck pusher rod. First, pull back the two handles on the staple gun's bottom to release the loading chamber. Pull the loading chamber out, up-end the gun and catch the staples as they fall out. Place the staples aside. Apply lubricating oil to a cotton swab. Wipe the inside edges of the loading chamber with the swab. Spray the spring covering the pusher rod inside the chamber with lubricating spray. Compress the pusher rod halfway with your fingers and hold it steady for 30 seconds before releasing it. Insert the staples into the chamber and return the chamber to the bottom of the staple gun.
A stuck staple at the end of the loading chamber will effectively render the Craftsman staple gun useless until it has been removed. First, pull back on the two handles at the bottom of the staple gun to release the loading chamber. Turn the staple gun upside down so that you can look down into the front lip at the end of the barrel -- don't' forget to catch the staples as they fall out of the chamber. Grip the stuck staple that is inside the front lip with the jaws of a needle-nose pliers. Pull the staple out and discard it in the trash. Turn the staple gun over. Reinsert the staples. Close the chamber.