Ygdras looked at the pieces and placed every fragment of the knife into its place. He brings out his Kyber Crystal and whispers, "Time to wake you up." With those words, he places the Crystal down by its cradle and sits down cross legged, closing his eyes as he let the Force guide his Lightsaber's construction.
The pieces began to levitate, arranging themselves to 'stand' where they needed to be. The Crystal drifted into its place inside the Lightsaber's core and the wires began to weave themselves throughout the weapon, connecting the power grid, emitter matrix and power cell to the rest of the saber. Screws and nuts nestled into their respective places, securing it all together, the metal fragments of the knife blade began assembling into the emitter's outer plating while the wooden handle contributed to the hilt. Silvery inlays settled into their homes as all the coverings and plates secured themselves with one final motion, taking all the small cables, screws, spacers and the Crystal at the heart of it all and making them into one form, one weapon.
OOC: I'll try to figure out a way to draw it or find some sort of reference image to use as a baseline.