Melt spinning apparatus

A melt spinning apparatus is disclosed which is adapted for dividing a molten polymer into a plurality of streams to form synthetic filaments. The apparatus comprises a spin block assembly having two opposite sides, and two separate heating chambers disposed adjacent respective ones of the sides of the spin block assembly. The two heating chambers are interconnected by threaded members, so that the opposing surfaces of the chambers may be drawn together to clampingly engage the opposite sides of the spin block assembly therebetween. The formation of air gaps between the opposing surfaces, and which might hinder the heat transfer between the heating chamber and spin block, are thereby avoided. In one embodiment, the threaded members extend through spacers which are mounted between the heating chambers and between adjacent spin block assemblies, with the spacers being essentially thermally nonconductive, and so that substantially all the heat flow to each spin block assembly is received from the opposing side wall surfaces of the two heating chambers.