Neither country was ever able to produce the amount of military war machinery that the U.S. did. We supplied Russia with complete factories so they could produce their own stuff. We sent civilian engineers, architects, etc. there to help them get the buildings up and running. We also sent them a vast amount of train engines and railroad cars. When Germany invaded Russia, Stalin had the people dismantle the factories so the Germans couldn't get their hands on them, and moved them by train farther into the interior, to be reconstructed in order to continue production.
Stalin was planning for war long before the war broke out. He was hiring American Advisers for his Industrialization program back in the late 1920’s and early 30’s. Russian industrial capacity by 1939 was awesome, then number of tanks and aircraft they had dwarfed Germany.
While Lend-Lease was important Russia had a formidable Industrial capacity.