Portable Mills Prove Their Worth in Fab Shop

“We actually own and have rented some other competitors' equipment, and for as long as I’ve been doing this – and I believe my crew would agree with me – there is no better equipment out there than the Climax equipment that we’re using. Hands down, there is absolutely no comparison.” 
-Dave Pettit, Portable Machine Works, Prairieville, LA

Situation

•  A fabrication shop in Texas received a contract to build a metal housing and platform for a small gas turbine unit -- essentially a "power plant in a box" -- for a leading supplier of power generation and energy delivery technologies. The shop manager wanted to do all the fabrication at their own location, mounting the finished assembly on metal skids and shipping to the project site from there. Uncertain how to machine a skid of the dimensions required, he turned to Climax Portable Machine Tools to determine if it could design, build and supply a specialized machine tool to do the job.
• Climax concluded that the most cost-effective method for machining these skids and related components on-site was with one of its portable linear mills. Because Climax manufactures tools but doesn’t do the actual machining, they referred the fab shop’s project manager to Steve Harrell at Portable Machine Works, a valued and trusted customer.
• In business since 1980, Portable Machine Works is a full-service company with both a machine shop and field machining operation. It has 50 employees and has built a reputation for excellent machining, serving companies in a wide range of industries including power generation, petrochemical, oil & gas, shipbuilding, paper mills and aerospace. Climax was confident that Harrell’s machinists, thoroughly experienced using Climax tools in the field, could meet the criteria set by the fab shop’s customer.

Challenge

• The machining project consisted of two skids - a large skid measuring 16 ft. x 60 ft., (4.8768 m x 18.28800 m) and a 6 ft. x 6 ft. (1.8288 m x 1.8288 m) sub-base skid, as well as several sets of mounting pads of various sizes and shapes. The smaller skid had mounting pads on the top and bottom, and was to mount on top of the larger skid to hold the gas turbine.
• In order to eliminate vibrations that could damage the turbine, all the skids and mounting pads had to be machined to extremely tight tolerances of 0.002-inches (0.0508 mm) so that the skids would lay flat and parallel to each other and the mounting pads would match and mate properly when the components were assembled.
• The fab manager was amenable to subcontracting the machining portion of the work, but wanted to closely supervise the work being done.

Solution

• Although Harrell's company owns several Climax machines, for this project he rented two Climax LM6000 portable linear mills and a PM2000 portable mill. The mills are modular, rugged, precision machines capable of meeting the close tolerances typically demanded by the power industry. Harrell’s crew, under the supervision of his field service manager, Dave Pettit, then set up operation in the fab shop.
• To machine the skids, the crew welded the LM6000s in place using gussets to support the milling machines. They then located the base plate onto the gussets and proceeded with the milling operation.
• The larger skid included 28 equipment pads of various sizes and shapes, ranging from 2-inch x2-inch (50.8 mm x 50.8 mm) to a  large midplate 8-foot x 6-foot pad (2.4384 m x 1.8288 m). Climax tools were used to mill the seven equipment pads for the smaller skid as well. Portable Machine Works machinists used the Climax PM2000 portable mill on the 2-in. x 2-in. (50.8 mm x 50.8 mm) equipment pads that were mounted on the perimeter of the larger skid. The modular design and portability of these mills allowed the machinists to move and easily mount them to the pads to machine them down to a desired height and flatness. 
• Once the skid was finished and the gas turbine placed on the skids, it was walled inside an enclosure and became a turbine package that is modular, mobile, and easy to set up at a plant.

Results

• Using laser tracking technology in combination with the machining operation, Portable Machine Works machinists were able to maintain tight tolerances of .002-inches (0.0508 mm) over the entire length of the skids and pads.
• Using portable linear mills for on-site machining shortened completion time. The initial skid machining project took two machinists just three weeks to complete. Moreover, Portable Machine Works has now completed many more of these “turbine in a box” projects, and with each new project the machinists have been able to further cut the machining time. Currently, it takes only 12 days to complete the task.
• Harrell believes there is no machine shop capable of machining these skids using a stationary tool. And the precision and versatility of the Climax mills allowed the fab to meet the requirements of its customers, keeping the entire operation in-house, and maintaining its high quality standards.
• Through the expertise of its machinists and the efficiency of its tools, Portable Machine Works was able to meet the stringent specs set by the fab shop’s customer, and do so in a cost-effective and timely manner.
• The turbine manufacturer was very pleased with the work, and has subsequently received numerous orders for these systems, for which Portable Machine Works continues to be the vendor of choice. For its part, Portable Machine Works believes the linear mills have more than paid for themselves by making seemingly impossible jobs routine.

“There is an old saying: ‘The best craftsmen are only as good as their tools.’ Climax tools and Portable Machine Works machinists’ have come together here to successfully “wow” the customer.”
– Geoff Gilmore, President, Climax Portable Machine Tools