Eccentric holes are needed in materials to be used in Measuring While Drilling component tools and operations. The location of the hole, in respect to the center of the bar, is precisely drilled off center. Typical positional tolerances are +/- .010" [0.25mm] throughout the length of the bar. This one is made of Inconel 718 and it is 109" [2,8 mt].
High performance steel bars of various sizes, which have been transformed into high performance tubes by drilling a hole through their centerline. The centerline of the hole is maintained within 0.005" [0,13 mm] of the centerline of the bar. This concentricity is maintained for the totality of it's length. The smaller tubes measure 1-11/16" [43 mm] in diameter by 7' [2,10 Mt] long. The large tube measure 4" [10,2 mm] in diameter by 17.4' [5,30 Mt] long. Both are made of Inconel, and are designed for a 27,500 psi [1.870 atm] pressure test.
Pressure Housings for down-hole logging tools.
Material: 17-4 PH Cond 1025.
3-3/8" [86 mm] diameter with a 2.753" [69.93 mm] honed hole, and 120" [3 Mt] long.
Wall thickness variation throughout the length: +/- 0.005" [0,13 mm]. Very important requirement for avoiding the failure of the Housing while subjected to the crushing pressures encountered in deep oil wells.
This is a typical job for us. The material is supplied by the customer, and the diameter of the bar, is the same as the diameter of the finished tube. For example: if the customer needs a 4.00" diameter housing, with a +/- 0.005" wall variation, he will supply a 4.00" diameter bar. This last statement is only meaningful to companies which are used to buying 5.00" dia bars for a 4.00" dia housing, and then turn to OD concentric to the ID's [needed because the hole normally drifts away from the center-line, during the drilling of deep (long) holes]. Our holes don't drift.
This is a mud passage hole, 1.00" [25,4 mm] in diameter, in a 5-1/2" [140 mm] diameter bar of stainless 17-4 PH, destined to become a Mud Motor Rotor. The length of the bar (and the hole) is 201" [5,10 Mt]. The concentricity of the hole, is +/- 0.005" [0,13 mm].
Alec is shining a light through the hole, to make it more visible.