Abstract: A fiber cutter for cutting lengths of glass fibers and glass rovings into short lengths includes a cutter roller carrying a plurality of cutting blades and shaped annular means cooperatively associated with a resilient back-up roll means. In operation the force executed between the cutter roller and the back-up roller controls the spacing between the rollers by forcing the shaped annular means into the resilient surface of the back-up roller means. In addition to permitting control of spacing, the coaction of the cutter roller with its shaped annular means and the resilient back-up roll means holds the rollers in alignment, reduces the bounce between the rollers as the blades engage and pass over the back-up roll means and permit force to be used to build the blades in engagement with the back-up roll means without blade breakage.