A method for machining a plurality of surfaces of a respective plurality of drawers in an article of furniture includes mounting the article of furniture to a support structure to form a work piece, positioning the work piece on a base of a vertical gantry router in an orientation such that the plurality of surfaces are generally perpendicular to a cutting head of the vertical gantry router, and machining the plurality of surfaces with the vertical gantry router until the plurality of surfaces are substantially flat and substantially coplanar with one another.

Provided is a manufacturing method for a compound screw having a first thread groove and a second thread groove with a different lead angle or lead direction from the first thread groove, wherein at least a portion of the first thread groove is formed by feeding a threading tool that acts on a workpiece a first feed amount toward the workpiece, the workpiece being a rotating object to be machined. Additionally, at least a portion of the second thread groove is formed by feeding the threading tool that acts on the workpiece a second feed amount that differs from the first feed amount. With these steps, a compound thread portion is formed in the workpiece. As a result, it is possible to mass produce a compound screw having two thread structures of differing lead angles and/or lead directions with a high level of quality.

A protection tool for an electronic drill provides various functions when drilling is carried out. The electronic drill has a front end with a through hole located at the front end and a drill head extending through out the through hole. The protection tool is moveably mounted at the front end of the electronic drill along an operation direction. A guard plate includes a pore aligning with the through hole and provides pass way for the drill head. A supporting frame is assembled with the guard plate and is moveably mounted at the front end of the electronic drill along the operation direction, so that the guard plate is positioned at a variable distance from the front end according to the movement of the supporting frame with respect to the front end.

A protection tool for an electronic drill provides various functions when drilling is carried out. The electronic drill has a front end with a through hole located at the front end and a drill head extending through out the through hole. The protection tool is moveably mounted at the front end of the electronic drill along an operation direction. A guard plate includes a pore aligning with the through hole and provides pass way for the drill head. A supporting frame is assembled with the guard plate and is moveably mounted at the front end of the electronic drill along the operation direction, so that the guard plate is positioned at a variable distance from the front end according to the movement of the supporting frame with respect to the front end.

An electronic drill with revolving replaceable drilling heads includes a housing, a driving unit, a rotary cover, and a plurality of drill heads. The housing has an opening, a through hole, a containing room connected therebetween. A motor container is disposed within the containing room to contain a motor of the driving unit. The rotary cover is assembled to the housing and is rotatable so that the plurality of drill heads coupled to the rotary cover is moveable freely in a rotary track between the motor container and the housing. One of the drill heads may be rotated to be aligned with a rotary hole of a gear set driven by the motor and pushed forward for use. The drill head can also be retracted backward and replaced in the electronic drill by rotating the rotary cover, so that another drill head can be pushed outward for use.

An electronic drill with revolving replaceable drilling heads includes a housing, a driving unit, a rotary cover, and a plurality of drill heads. The housing has an opening, a through hole, a containing room connected therebetween. A motor container is disposed within the containing room to contain a motor of the driving unit. The rotary cover is assembled to the housing and is rotatable so that the plurality of drill heads coupled to the rotary cover is moveable freely in a rotary track between the motor container and the housing. One of the drill heads may be rotated to be aligned with a rotary hole of a gear set driven by the motor and pushed forward for use. The drill head can also be retracted backward and replaced in the electronic drill by rotating the rotary cover, so that another drill head can be pushed outward for use.

The removal starting position (8S1) of a first removal process and the four removal starting positions (8S21-8S24) in a second removal process are established on an imaginary circle (7I) with a prescribed radius (R) that is inscribed in the apex (7C) of an incomplete thread part (7a). In each removal process, the tip of the screw thread cutting tool shaves off the apex (7C) of the incomplete thread part (7a) into respective recesses, contacting the imaginary inscribed circle (7I) from the outside (above). The multiple cutting surfaces of the apex (7C) are formed in parallel helices (that is, as mutually adjacent helical recesses) from the starting position to the ending position of the incomplete thread part. Points and burrs in the incomplete thread part can thereby be eliminated or reduced without loss of the ability to screw together with a partner threaded fastener (threaded portion).

The removal starting position (8S1) of a first removal process and the four removal starting positions (8S21-8S24) in a second removal process are established on an imaginary circle (7I) with a prescribed radius (R) that is inscribed in the apex (7C) of an incomplete thread part (7a). In each removal process, the tip of the screw thread cutting tool shaves off the apex (7C) of the incomplete thread part (7a) into respective recesses, contacting the imaginary inscribed circle (7I) from the outside (above). The multiple cutting surfaces of the apex (7C) are formed in parallel helices (that is, as mutually adjacent helical recesses) from the starting position to the ending position of the incomplete thread part. Points and burrs in the incomplete thread part can thereby be eliminated or reduced without loss of the ability to screw together with a partner threaded fastener (threaded portion).