91ÊÓƵÍøÕ¾ÎÛ

Manufacturing submarine parts doesn’t just mean meeting a tight tolerance on each part. It also means that features on multiple discrete parts must be machined, positioned and welded so that they are within a few thousandths of an inch in reference to one another. , a job shop focused on submarine production with locations in Manchester, New Hampshire, and Nashua, New Hampshire, is very particular about its machines as a result. When looking to increase the maximum size of parts it could produce, it looked for machines that would also improve part access, and which would hold tight tolerances across large parts. This led Granite State to purchase two five-axis Soraluce machines, which have not only expanded its potential range of jobs but also attracted experienced machinists.

On Becoming a Submarine Specialist

Granite State has existed at its Manchester location for 85 years and has long found that it was most competitive and successful with larger parts. For most of its history, the shop has served a wide range of markets using a variety of vertical machining centers and several DMG MORI Kuraki three-axis horizontal boring mills.

The shop’s business focus began to change around 2018 as and the U.S. Navy began a push to greatly increase the rate of submarine construction. Granite State decided to expand its presence in this market and bought its Nashua site — a former Ingersoll pulp and paper mill equipment manufacturing plant — on account of its 30-ton bridge cranes and 35 feet of space under the crane hooks.

Building out this site was also much swifter than expected, due in large part to its success in applying for Supplier Development Funding (SDF). This is Congressionally apportioned money for building out the U.S. industrial base, says Granite State Vice President Doug Thomson, and while it doesn’t just apply to submarine construction, Granite State’s stated goals helped it gain enough funding to pay for one of the Soraluce machines, as well as machines for large-format welding. Now, both the Manchester and the Nasuha facility work to build systems for Virginia- and Columbia-class submarines, spare parts for sustainment and parts to help fulfill the AUKUS agreement to provide Australia with nuclear submarines.

The timetables for fulfilling these orders go out years, with Thomson saying that some of the order contracts being signed now are for parts that will be fulfilled years after he has retired. While he finds this — and the shop’s current near-exclusive focus on submarine parts — nerve-wracking, he also admits that it is great for job stability, and the knowledge that the shop is contributing to national security goals helps with employee morale (especially for veterans).

Welding + Machining

Much of Granite State’s work is in steel and stainless steel, but it also performs some work in nickel, copper, nickel alloys and bronze. These materials have challenging characteristics that require deep institutional knowledge on the cutting parameters necessary for each material. This also holds true for welding, and Granite State has needed to seek certifications to be able to weld several alloys. Thankfully, Thomson says, these certifications have strengthened the company’s bids and enabled it to win more work.

The company’s parts can fit in a person’s hand on the small end, but most of the parts are far larger. Thomson points to one recent part, a 15-foot by 12-foot by 1.5-foot support base welded together from smaller pieces machined on the company’s mills. Thomson also says that Granite state is targeting even larger parts — just so long as they can fit on a truck for delivery.

The need to combine welding and machining comes down to a simple fact: large-format welding can only be so precise, and meeting features’ tolerances in relation to one another is beyond what large-format welding can do on its own. Moving parts back and forth between the machining and welding departments requires more setups, but Thomson says that it ultimately leads to better accuracy. Another key challenge comes from the additional CAD work necessary. Granite State receives drawings of the whole part, but uses SolidWorks to design the individual pieces and determine how to weld them together.

Flexible Five-Axis

While Granite State was confident in its ability to weld the individual pieces together, creating these individual pieces could still be a challenge due to their size and difficulties in accessing certain features. These considerations made the sheer size and five-axis capabilities of Soraluce’s FP10.000 floor-type mill points in its favor. The shop also soon bought a Soraluce FLP6000 with its SDF funding. Although this machine has smaller (though still large) travels than the FP10.000, it also includes a 1,600-mm-diameter multitasking table with floor plates on both sides of the rotary table to improve flexibility.

Granite State is careful about which jobs it performs on these machines. For hogging out material, the company’s large DN Solutions three-axis boring mill is faster, but for finishing operations on weldments or jobs requiring complex access, the Soraluce machines are better suited for the task. The shop is also careful to maintain a fleet of broad-usage machines to ensure the backlog for the Soraluces is as small as possible. After all, Thomson says, “the largest machine in your shop will always be busy because once you have that large machine, everybody now knows you can do that work,” and the Soraluce machines have been consistently busy since their purchase in 2020.

Both Soraluce machines bear the OEM’s Dynamic Active Stabilizer technology, which counters harmonics to reduce chatter when cutting thin parts and when working far away from the machine base. As floor-type machines, the machine control area and pendant travel the longitudinal X-axis (10,000 mm on the FP10.000 and 6,000 mm on the FLP6000), though the pendant itself still travels on its own for the Y-axis vertical travel and Z-axis cross travel (3,200 mm and 1,600 mm respectively on the FP10.000 and 2,200 mm and 1,500 on the FLP6000). The large table sizes enable Granite State to perform pendulum milling — setting up two parts at the same time at safe distances. Thomson says this is less about being able to set up one part while machining the other than it is about enabling in-machine inspection for large parts while not slowing down the overall job.

In addition to being a draw for additional large-format work, Thomson says the Soraluce machines have been a recruitment draw for experienced machinists. These large-format, five-axis machines are not a great fit for new machinists, he continues, especially for exacting parts with no automation. “It takes a certain amount of skill and confidence,” he says, and “if something goes wrong, if you mess something up, everybody’s going to know. It’s going to be expensive.” But for skilled machinists, these demands can appeal to their sense of professional pride. As Thomson puts it, “If you are the best machinist in the area and people want your services, do you want to be on the brand-new, high-performance, 30-foot-long machine?”

In Granite State’s experience, the answer has been a resounding “Yes.”

Creating a Talent Pipeline

Fighting for long-time machinists is not Granite State’s only recruitment strategy. The company also has a relationship with and , acting in concert with these institutions to run programs similar to the U.S. Navy’s (ATDM) program in Virginia, and General Dynamics Electric Boat’s program at the in Rhode Island.

The machining program at Nashua Community College is at 10-week, 40-hours-per-week training course paid in full by the U.S. Navy, built on top of the ATDM curriculum but with additional refinements stemming from Granite State’s needs and feedback provided by New England Tech’s instructors. Thomson says that the program has effectively eliminated the need to hire employees with no machining experience, as Granite State can point potential applicants to the program to build a skill foundation. The community college system can also provide additional tutoring on math and other necessary skills that would be outside the purview of a typical training program, and Thomson says that stipends and scholarships through the government and other organizations can help fund students’ living expenses while they complete the course.

When I spoke with Thomson in January 2025, the Nashua machining program was about to start its sixth cohort of 10-12 students, and the Manchester welding program its third cohort of students. While Granite State does not have the capacity to take on every graduate as a new hire, it has been able to fill its entry-level openings with each graduating cohort, with other students quickly finding employment at the nearby naval shipyard or with other local manufacturing shops.

In what has been an unexpected benefit, involvement with the programs has also improved Granite State’s ability to hire skilled machinists. When press releases about the shop’s involvement go live, Thomson says, applications from experienced machinists rise, as they seek an employer who is investing in the future.

This investment is also expressed through a higher budget for third-party training — even with the move away from training completely fresh employees — and a clear structure for career advancement at Granite State. Fresh graduates from the Nashua and Manchester programs start with the smaller-scale tasks and get assigned mentors from the more experienced machinists and welders. As these new hires hone their skills (whether on a single machine or with multiple), they meet criteria jointly set by Granite State’s HR team and experienced shopfloor staff for pay and title increases. As Thomson puts it, “Skillsets get paid . . . not seniority.”

In addition to improvements in individuals’ skills, Thomson says that Granite State management tries to make it clear to all employees that they want to hear about spots for potential process improvements. The company has funding for continuous improvement projects, and if staff can specifically identify how a process change will benefit a job, Thomson says that both Granite State and the U.S. Navy will be receptive to spending the money for it. For Granite State, this is a simple calculation, as while investments in machinery and fixturing may cost more in the present, they will pay dividends over the long course of its submarine projects.

Purchasing the Soraluce FLP6000 started out as this sort of calculation, Thomson says, as management realized that they would be able to complete more machining operations in one setup by putting parts on a turning table. As for the rest of the benefits they’ve gotten from both machines — those are bonuses.