High Precision Machining of Components for Vital Infrastructure
IPM Assists in Fabricating Dam Replacement Parts with Close Tolerance High Precision Machining
Pacific Northwest -- Thompson Metal Fab out of Vancouver, WA recently contracted with In-Place Machining Co. to machine close tolerance features on large fabrications of two closure leaf assemblies for the McNary Dam. These leaves are approximately 17’ high, 53’ wide and 5’ deep and weigh approximately 120,000 lbs. The close tolerance requirements required for the guide rollers, lock pins and lifting lugs necessitated machining after fabrication had been completed, and the leaves were much too large to fit on conventional machining equipment.
Thompson Metal Fab called upon the expertise and unique abilities of In-Place Machining Company to help in high precision machining of these specialized components. Through partnership with IPM, the team was able to hold the close tolerances for various hole sizes and locations that the project demanded, and perform machining operations on part sizes not otherwise possible.
The McNary Dam is a 1.4-mile long concrete gravity run-of-the-river dam which spans the Columbia River. The two new closure leaves were manufactured for the operation of the Top Spillway Weirs (TSW) at McNary Dam. The closure leaves are designed to stop and start flow over the TSW’s to pass migrating juvenile salmon. When infrastructure of this size and scope requires replacement parts, only the specialized services of In-Place Machining Company can get the job done.
Precision Optical Inspection & Alignment
IPM used precision optical alignment tooling to set up the line boring equipment to hold co-axiality and parallelism of the (6) guide wheels of 0.010” over 53 ft x 9 ft, and hold bore tolerance of +0.0012” – 0” using custom designed micro-adjust boring heads.