Abstract: A drill bit assembly for measuring reservoir formation properties comprises a bit head and a pin body, and an electrically insulated gap joint between two conductive parts of the drill bit assembly. The bit head has a cutting end and an opposite connecting end with an engagement section. The pin body comprises a connecting end with an engagement section. The pin connecting end is connected to the bit head connecting end such that the engagement sections overlap. The electrically insulating gap joint can fill a gap between the bit head and pin body engagement sections such that the bit head and pin body are mechanically connected together at the connecting ends but electrically separated. Alternatively or additionally, the pin body can have two pieces which are separated by an electrically insulating gap joint.