a method of making a solid wall sheath for use on probes of electronic thermometers . the resultant sheath is of tapered configuration , having a wall thickness adjacent a small closed tip end of between 0 . 005 inch and 0 . 012 inch . the sheath is formed by injecting a suitable plastic material into a mold around shaped inserts or mandrels , through an orifice opening having a throat diameter of from 0 . 007 inch to 0 . 0021 inch .