There are several methods of fastening the ends of belts together. It is customary in the case of wide belts (8 in. and over) to fasten the ends by cementing. Narrow belts are fastened by lacing, wiring, hooks, or any one of the numerous forms of belt-fasteners on the market. The smooth or hair side of a belt should run next to the pulley with the flesh side out, as this latter side is softer than the other. While belts must be made tight enough to run the machine, they should never be tight enough to strain the journal bearings, or excessive heat and wear will result.