an apparatus and method for injection molding of thermoplastics has elements and steps comprising mating mold components having multiple mold cavities with flow passages and a plurality of conduits connected to the mold cavities so that thermoplastic can flow into the cavities . a plurality of flow control members are mounted relative to the mold and to corresponding conduits to be moved to regulate the flow of plastic through corresponding conduits into corresponding cavities to allow for controlling the rate of thermoplastic flow among the cavities . the flow control member can each have a first member movable into its corresponding conduit , and a second adjusting member movable to engage and move the first member . a biasing member can be provided to bias the first member relative to its corresponding conduit . the control members can be inserted to varying degrees within their corresponding conduits to control thermoplastic flow rate among the mold cavities . the flow control member can be controlled by structure external to the mold to allow adjustment of the flow control member . a modification provides for bores extending through outer end surfaces of mold components at an angle of about 45 ° to about 60 ° relative to their corresponding mold outer surface . in the modification , a control member can have a threaded section that mates with mold bore threads . the control member can have a non - threaded section distal thereto , a part of which is received within the non - threaded part of the bore for guidance during movement .