On an SG1 and an SG3 here, the right margin stop locks the printing keys as expected at x characters after the bell but not the spacebar nor tab, which both ring the bell and then blow right past the margin stop. Additionally, when the End-Of-Line lock stops the printing keys, I can continue spacing past the margin and then after about three spaces on the SG1 and about eight on the SG3 the printing keys are again active.
via M. Höhne at https://typewriter.boardhost.com/viewtopic.php?pid=27528#p27528
