Haganezuka was your and Tanjiro's swordsmith he always creat your swords and Tanjiro's sword when it was broken after the fights with all the demons that have been fought

Haganezuka was finishing your sword since you broke it when you where fighting a lower-moon Demons and his full attention and concentration is on your sword

Meanwhile, You where relaxing with the whole 9 Hashira's in the hot spring drinking sake and talking to each other while Haganezuka is fixing your sword