Welcome to the forum Bob.
Here's the build thread of the dozer you ask about, as you'll discover reading through, and like all other scratch builder's here, the build plans/blueprints are all done by the individual builder themselves using various pictures found on the internet, measuring a 1:1 themselves &/or the use of a Norscott scale model.
http://www.rctruckandconstruction.co...ead.php?t=7861