A vegetation trimming assembly has at least one cutting blade with a cutting edge that moves guidingly within a blade working space between facing first and second fixed surfaces. The first surface is defined in part by a body with a fixed shape, including a head and a stepped diameter shank with a larger diameter portion to guide movement of the one cutting blade and a smaller diameter portion that is threaded to engage a support defining the second surface. The body is selectively turned in opposite directions to thereby increase and decrease a depth of the blade working space.
