A drill bit for rock drilling tools includes a drill bit head having a front surface including a face surface defining a forward-most end of the drill bit head. The face surface has an outer edge, a gauge surrounding the face surface, the gauge having an inner edge, and a transition region that extends in a direction of a longitudinal axis of the drill bit between the outer edge of the face surface and the inner edge of the gauge. An entirety of the face surface from which the cutting surfaces extend is non-flat so that a center of the face surface is axially forward of the outer edge of the face surface. The gauge includes a first gauge surface defining a first angle with the longitudinal axis over a first portion of a circumference of the gauge and a second gauge surface defining a second angle with the longitudinal axis over a second portion of the circumference of the gauge.

A retaining system (100) for a DTH hammer drill bit (25) having an outer surface with a plurality of stops (31) at an up-hole end (29) of the drill bit (25) the stops projecting radially outward from the outer surface and spaced by respective gaps (35). The retaining system has a ring (102) which is configured to pass over the stops (31) when in a first rotational position relative to the drill bit (25). However when the ring (102) is in a second rotational position relative to the drill bit (25) it prohibits passage of the stops (31) through the ring (102).

A retaining system (100) for a DTH hammer drill bit (25) having an outer surface with a plurality of stops (31) at an up-hole end (29) of the drill bit (25) the stops projecting radially outward from the outer surface and spaced by respective gaps (35). The retaining system has a ring (102) which is configured to pass over the stops (31) when in a first rotational position relative to the drill bit (25). However when the ring (102) is in a second rotational position relative to the drill bit (25) it prohibits passage of the stops (31) through the ring (102).

A drill bit for percussive rock drilling tools includes a drill bit head having a front surface including a face surface defining a forward-most end of the drill bit head and at least one hole in the drill bit head for receiving a button. The drill bit includes at least one recess located in the face surface. The recess is larger than the hole. The hole is disposed in the recess so that an open end of the hole is disposed below the face surface. The drill bit head further includes a gauge surrounding the face surface, the recess being partially disposed in the gauge.

A drill bit for percussive rock drilling tools includes a drill bit head having a front surface including a face surface defining a forward-most end of the drill bit head and at least one hole in the drill bit head for receiving a button. The drill bit includes at least one recess located in the face surface. The recess is larger than the hole. The hole is disposed in the recess so that an open end of the hole is disposed below the face surface. The drill bit head further includes a gauge surrounding the face surface, the recess being partially disposed in the gauge.

A drill bit for percussion drilling includes a drill bit body including a front surface. The front surface includes a first circular area arranged transverse and coaxially to the axis of the drill body, a second area surface surrounding the first area surface, and a third area surface surrounding the second area surface. A number of buttons are arranged in the second and third area surfaces. The button body of each button has a forward end surface. The buttons are arranged in circular recesses extending substantially transverse from the second surface and third area surface into the drill bit body. The recesses have a radius corresponding to the button body radius and a depth corresponding to the length of the button body, such that the button bodies are fitted within the drill bit body with the forward end surface exposed in the second and third area surfaces.

A method for estimating wear of a drill bit in percussive rock drilling. A percussion device is configured for generating shock waves in a drill bit for breaking rock. The method includes, during drilling determining a percussion frequency of the percussion device; and estimating wear of the drill bit based on the determined percussion frequency of the percussion device and a model representation of the wear of the drill bit as a function of percussion frequency, wherein the model representation is configured to output the estimated wear of the drill bit utilizing the determined percussion frequency as input signal.

A method for estimating wear of a drill bit in percussive rock drilling. A percussion device is configured for generating shock waves in a drill bit for breaking rock. The method includes, during drilling determining a percussion frequency of the percussion device; and estimating wear of the drill bit based on the determined percussion frequency of the percussion device and a model representation of the wear of the drill bit as a function of percussion frequency, wherein the model representation is configured to output the estimated wear of the drill bit utilizing the determined percussion frequency as input signal.

A bit for a percussive hammer includes an elongated shank, a head at a first end of the shank, and an array of lengthwise extending spline portions defining outwardly extending retention lugs at or toward a further end of the shank. At least a side face of at least one lug is blended into the shank of the bit.

A bit for a percussive hammer includes an elongated shank, a head at a first end of the shank, and an array of lengthwise extending spline portions defining outwardly extending retention lugs at or toward a further end of the shank. At least a side face of at least one lug is blended into the shank of the bit.