A rigid endoscope includes an outer housing subassembly that supports an optics subassembly. The outer housing subassembly includes concentric tubes with optical fiber for providing object illumination. The optics subassembly includes a tubular sheath sealed at both ends for carrying lenses and other optical elements. A slow-curing adhesive material fills an annular gap between the optics and outer housing subassemblies. The adhesive material has a tear strength that seals and positions the optics subassembly for normal use and that enables the optics subassembly to be withdrawn from the outer housing subassembly for repair.