The root √KHEP appeared with gloss “retain, keep, do not give away or release, keep hold of” in etymological notes from 1959-60 along with a variant √KHAP “bind, make fast, restrain, deprive of liberty” (VT41/6), and in this period it was almost certainly the basis for S. heb- “keep” in ú-chebin estel anim “I have kept (heb- lenited 1st-person) no hope for myself” (LotR/1061). It might be a later iteration of ᴱ√HEPE, glossed “bind” in the Qenya Lexicon of the 1910s (QL/40) and “encircle?” (the question mark is Tolkien’s) in the contemporaneous Gnomish Lexicon (GL/48).
Neo-Eldarin: For purposes of Neo-Eldarin, some derivatives of this 1910s root might be salvaged as derivatives of later √KHEP.
A root appearing in a list of Sindarin words placed with Definitive Linguistic Notes (DLN) from 1959, given as √REÞ or √RES “remain in same place, hence be unmoved, patient”. It had the derivatives S. andreth “patience”, which appeared elsewhere as the name of a Bëorian woman (MR/305), and S. Arodreth “Noble Endurance”, a name appearing nowhere else. The variant √RES may have been intended to be the Quenya form.