A guide for a traveling transmission medium such as a timing chain comprises a resin shoe for sliding contact with the transmission medium, supported on a base frame having an two flanges and a web in an I-shaped cross-section. The base frame is produced from aluminum by die casting, using a three-part mold. Two parts of the mold cooperate to form a part of the mold cavity that forms one of the flanges and the web of the base frame, and a third part of the mold cooperates with the first two parts to form a part of the cavity in which the other flange of the base frame is formed without a draft.