810 Hand and Power Tool Safety

Nail Gun Trigger Types

All nail guns rely on two basic controls:

1. a finger trigger, and
2. a contact safety tip located on the nose of the gun.

Also, trigger mechanisms can vary based on:

1. the order in which the controls are activated, and
2. whether the trigger can be held in the squeezed position to discharge multiple nails OR if it must be
3. released and then squeezed again for each individual nail.

Combining these variables gives four kinds of triggers. Some nail guns have a selective trigger switch which allows the user to choose among two or more trigger systems.

Nail Gun Trigger Types

Each trigger type is described below along with a summary of how the controls are activated.

Full Sequential Trigger

This is the safest type of nail gun trigger. This trigger will only fire a nail when the controls are activated in a certain order. First, the safety contact tip must be pushed into the work piece, then the user squeezes the trigger to discharge a nail. Both the safety contact tip and the trigger must be released and activated again to fire a second nail. Nails cannot be bump fired (see below). Also known as single-shot trigger, restrictive trigger, or trigger fire mode.

Contact Trigger

This trigger will only fire a nail when the controls are activated in any order. You can push the safety contact tip first and then squeeze the trigger, or you can squeeze the trigger first and then push the safety contact tip. If the trigger is kept squeezed, a nail will be driven each time the safety contact is pushed in. All nails can be bump fired. Also known as bump trigger, multi-shot trigger, successive trigger, dual-action, touch trip, contact trip, and bottom fire.

Single Sequential Trigger

Like the full sequential trigger, this trigger will only fire a nail when the controls are activated in a certain order. First, the safety contact tip must be pushed into the work piece. Then, the user squeezes the trigger to discharge a nail. To fire a second nail, only the trigger must be released. The safety contact tip can stay pressed into the work piece. Nails cannot be bump fired.

Single Actuation Trigger

Like the contact trigger, this trigger will fire a single nail when the safety contact and trigger are activated in any order. A second nail can be fired by releasing the trigger, moving the tool and squeezing the trigger again without releasing the safety contact tip. Note that some manufacturers refer to these triggers as "single sequential triggers", but they are different. The first nail can be bump fired with a single actuation trigger but not with a true single sequential trigger.

For more information on nail gun safety, see Nail Gun Safety A Guide for Construction Contractors.

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