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 drill bit includes a shank, a transition portion, and a body portion defining a plurality of axially stacked, progressively sized steps. The steps include a first step and a terminal step coupled to the transition portion. The first step defines two tip flutes each disposed at a tip flute angle. The body portion defines a body flute extending from the first step to the transition portion. The drill bit also includes an indicator band formed on a portion of the body flute and a portion of an outer surface of one of the plurality of steps.

A candle assembly for making a personalized scented candle including a candle body comprises a coring device that is configured to remove a core from the candle body, the coring device including (i) a leading edge that selectively extends into the candle body; and (ii) a plurality of measurement markers that measure a depth of the leading edge within the candle body. The coring device can be configured to remove the core from the candle body to form a cavity in the candle body. Additionally, the measurement markers can be utilized to determine a depth of the cavity formed in the candle body by the coring device.

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.

A drill cutting insert has a cutting edge at a transition between a side surface and a top side which is formed with n identical cutting corners and n identical partial cutting edges with n{3, 4} extending between the cutting corners. Each of the n partial cutting edges has: adjoining a first cutting corner, a main lip which is straight in plan view of the top side; adjoining the other cutting corner, a secondary lip which is straight in plain view of the top side, and a transition section, via which the main lip and the secondary lip merge into one another and which has a convex section adjoining the main lip and a concave section adjoining the secondary lip. The main and secondary lips enclose on the outside an angle a <180 in plan view of the top side.

A drill bit includes a shank and a body portion defining a plurality of axially stacked, progressively sized steps. The steps include a first step and a terminal step. The first step defines two tip flutes each disposed at a tip flute angle. The body portion defines a body flute extending through the steps. The drill bit also includes an indicator band formed on a portion of the body flute and a portion of an outer surface of one of the plurality of steps.

A drill bit includes a shank extending along a bit axis and a body portion coupled to the shank. The body portion having a distal end and defining a plurality of axially stacked, progressively sized steps. The body portion defining a body flute having a flute surface. The drill bit includes a first indicium formed on the flute surface adjacent a first step of the plurality of steps, the first indicium including a number and an indicator band around the number and a second indicium formed on the flute surface adjacent a second step of the plurality of steps and spaced from the first indicium, the second indicium including a number and an indicator band around the number, wherein the first indicium is spaced from the second indicium by at least one step of the plurality of steps.