Abstract: Ratchet mill assemblies to permit precise horizontal cutting, one ratchet mill assembly comprising: a shaft with polygonal cross-section, wherein the shaft with polygonal cross-section can rotate and is supported by bearing brackets where each bearing bracket is attached to an end bracket; a handle bar coupled to end brackets by a handle boss on each end bracket; two pinion sprockets coupled to the shaft with polygonal cross-section; and two depth posts, each depth post having depth markings, and each depth post having a corresponding end bracket held in place on the corresponding depth post by a post clamp, wherein at least one post clamp is secured and tightened by way of a half U-bolt and a toggle lock clamp, wherein each pinion sprocket engages rack holes on a corresponding depth post to allow movement of a corresponding end bracket up and down the corresponding depth post.