Interlocking sectional tubing

An interlocked tube comprising:

• a first pie cut tube section defined by a substantially circular first front face and a substantially circular first back face,
• a first minimum face-to-face distance between the first front face and the first back face, the first minimum face-to-face distance is smaller than a first maximum face-to-face distance between the first front face and the first back face, and
• a plurality of evenly spaced keys dispersed along the first front face of the first pie cut tube section;
• a second pie cut tube section defined by a substantially circular second front face and a substantially circular second back face,
• a second minimum face-to-face distance between the second front face and the second back face, the second minimum face-to-face distance is smaller than a second maximum face-to-face distance between the second front face and the second back face, and
• a plurality of evenly spaced facets dispersed along the second back face of the second pie cut tube section;
• a weld that seals a joint between the first front face and the second back face;
• and
• at least one tack under the weld, the tack connecting one of the plurality of facets to one of the plurality of keys, and
• wherein each of the keys are substantially triangular shaped and each of the facets comprises a substantially triangular shaped major portion and a detolerance window, the detolerance window having a different shape than the substantially shaped major portion and extending from an apex of the substantially triangular shaped major portion.

A method to connect a first pie cut tube section to a second pie cut tube section, the method comprising:

• orienting a first pie cut front face of the first pie cut tube section with a second pie cut back face of the second pie cut tube section;
• next, meshing together a plurality of keys equally spaced on the first pie cut front face with a plurality of facets equally spaced on the second pie cut back face;
• next, tacking at least one of the plurality of keys to a corresponding one of the plurality of facets;
• next, welding a contiguous seam along the first pie cut front face and the second pie cut back face,
• the first pie cut tube section defined by a minimum face-to-face distance between the first pie cut front face and a first back face of the first pie cut tube section, the minimum face-to-face distance is smaller than a maximum face-to-face distance between the first pie cut front face and the first pie cut back face, and
• wherein each of the keys are substantially triangular shaped and each of the facets comprises a substantially triangular shaped major portion and a detolerance window, the detolerance window having a different shape than the substantially shaped major portion and extending from an apex of the substantially triangular shaped major portion.