Abstract: An impact device, useful for driving nails, staples and other fastening elements. The driving member is driven by frictional engagement with a rotating high speed flywheel. The device has a safety provision whereby it cannot be actuated until the nose of the device is pressed against a work piece. This action also produces a movement of a support means, such as a roller, towards the rotating flywheel. It should be pointed out that the tool could be designed, in the alternative, with a fixed support means and movable flywheel. Actuation of the trigger moves the driving member into engagement between the support and the rotating flywheel, and the flywheel propels the driving element in a fastener driving direction. The support means is provided with a leaf spring permitting it to yield so that the driving member can pass between the flywheel and the support means while maintaining frictional engagement between the flywheel and the driving member.