Turbine Shaft Housing Part III
Construction continues on the Turbine Shaft Housing.
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Rather than using math or a DRO to lay out the holes
in the rear of the gear case, we can make good use of a
bearing and the 10-32 spigot retaining screw to
temprarily hold the two parts together in perfect
alignment. A streak of blue helps to identify the holes. First, a bearing is inserted into the housing. Since the bearing bore depth is only 3.35mm, a good portion of the bearing protrudes. This is inserted into the gear case, and the bearing acts as a dowel pin to align. The housing is rotated so that the spot-faced 10-32 spigot hole is aligned, and a 10-32 cap screw is used to secure. |
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Using a close-fitting drill, the hole locations are marked by hand. After the shaft housing is removed, the spots are first prick punched, then centre punched. Drilling and tapping 4-40 / 3mm completes the operation. The parts are deburred and generally cleaned. |
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The housing firmly mated with the gear case. Note that I still haven't beveled the rear of the gear case... leaving this square for now gives me workholding options for later turning and/or milling operations. Note too how the spigot retaining screw becomes part of the security of the shaft housing. It looks neat, too. |
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The other side of the gear case, with the prop shaft housing mounted. There is still no udercut. Again, this is left solid for now. |