A pneumatic sanding machine includes a body, a pneumatic motor assembly mounted in the body and a control valve detachably mounted in the body to change the path of compressed air that actuates the sanding machine. The control valve includes a first portion selectively closing one of different air passages in the body at a time, a second portion and a neck portion interconnecting the first portion with the second portion. Thus, a dust bag or a vacuum cleaner can be connected to the sanding machine to collect dust or sanding debris so that the sanding machine provides three different ways of dust collection, one of which is not to deal with the powder, the second is to collect the powder into a dust bag, and the third is to vacuum the powder into a vacuum cleaner.

An electric hand power tool has a housing, an air-cooled electric motor which is accommodated in the housing, a tool which is driven by the electric motor a protective hood which at least partially covers the tool, the housing having a handle and an auxiliary handle for a two-hand guidance of the hand power tool, the auxiliary handle being positioned in a plane transverse to a plane of the first-mentioned handle and, with reference to a work direction, before the first-mentioned handle, the auxiliary handle being completely hollow and having an inlet communicating with the protective hood so as to carry motor cooling air which has left the housing and passed the protective hood for the tool and then flows into the inlet of the auxiliary handle carrying debris and through the auxiliary handle and out of the latter, so that the auxiliary handle is operative for damping a flow noise of the air from the electric motor, from a motor-cooling fan and from the tool.

A pneumatic buffing machine including a housing having an internal chamber in which a pneumatically driven motor set is mounted. The motor set includes an eccentric block for driving a grinding disc. A skirt shade is screwed under a bottom of the housing by means of outer thread and inner thread. The skirt shade has a large diameter section and a small diameter section. The skirt shade is formed with a central through hole. The eccentric block of the motor set is passed through the through hole and accommodated in the large diameter section. A shoulder section is formed between the large diameter section and the small diameter section and adjacent to the outer thread of the small diameter section. A top end of the small diameter section serves as a stopper section. When the skirt shade is screwed into the chamber of the housing, the bottom end of the housing abuts against the shoulder section to tightly fix the skirt shade and the stopper section abuts against the bottom of the motor set to fix the motor set in the chamber of the housing.