Here is a specialty Shipyard job we did last week on a new 3200 Horsepower Tug for NGL. We are drilling the Reduction Gear/Clutch foundations. Each gear has eight 1 1/2 inch bolts. The four corner bolts on each foot are "body fit", which keep the gear from shifting under normal operation.
We set up jacking screws on every corner, and align the Gear Output Coupling to the Propellor Shaft Coupling. Everything has to be cinched tight so nothing can shift during the drilling operation.
We machine the Body Fit bolts from Grade 8 blanks we buy. They are fit with .001 interference fit. I soak them in liquid nitrogen for about 20 minutes and slip them in. The inner bolts on the Gear Foot just get Grade 8 non fitted bolts.
I use a big #4 Ingersol Rand Pnuematic Corner Drill and fabricated mount that more ore less makes it a portable drill press. I place it where the bolt is to be, and tack weld it in place. Each drill has it's own guide bushing. It might look a tag crude, but with this, we can drill and ream extremely precision holes quite efficiently.
After we install the bolts, the Shipyard will pour "Chockfast Orange" Chocks to complete the setting in of the Gear.
If you notice the plate between the Gear Foot and the foundation, it i there because when using Chockfast, the thickness of the chock cannot exceed 1 3/4 inchor be less than 1/2 inch. These would be 2 1/4, so you include the plate so you have two 3/4 thick Chocks.
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http://chockfast.com/products/two-component-epoxy-chocking-compounds/chockfast-orange/