The Sprint Cup race series sanctioned by NASCAR (the National Association for Stock Car Auto Racing ) is one of North America’s biggest spectator sports. Perfectly choreographed for a television audience, it involves 36 races taking place over a 10-month period. In terms of viewing figures, its popularity is second only to the National Football League.
Haas Automation founder Gene Haas and three-time Sprint Cup Champion Tony Stewart jointly own Stewart-Haas Racing (SHR). In the 2012 season, the team fielded three drivers: Tony Stewart himself, Ryan Newman and Danica Patrick. The SHR headquarters is a long, rectangular building, the central part of which is a cavernous space filled with racing cars in various states of preparation. To the right of the main workshop is the team merchandise store, and to the left — behind a glass partition — is the team machine shop, which is fronted by a red, special-edition Tony Stewart VF-2 vertical machining centre. Unsurprisingly, every single CNC machine tool in the shop is a Haas machine
(www.haascnc.com).
Brad Harris, machine shop manager, says: “It’s natural that we have Haas machines as opposed to other makes. That said, they are versatile and reliable, which is precisely what our work demands; and having one make of machine with a single control helps scheduling. There are just five of us here, and between us we take care of all 12 machines — eight VMCs and four turning centres. Four of the VMCs have four- and five-axis capability, which means we can make pretty much whatever our car teams need, with minimum set-up times.”
Frequent modifications
“Mid-season, modifications are happening all the time, sometimes due to NASCAR rule changes, and sometimes because an engineer or crew chief comes up with an idea to improve the performance of the cars. “In all cases, they’ll want the part immediately,” says Mr Harris. “However, by the time the change has been through the engineering department and filtered through to the machine shop, there’s usually not much time left. As a result, every job is an emergency.”
The biggest machines on site are two VF-6TRs with trunnion tables. There are also a Mini Mill, a VF-2, and a VF-4 five-axis machining centre, also fitted with a trunnion (a TR-210). Like all race teams, SHR is reluctant to show most of the components it makes in-house close-up, although one of the most recognisable parts is the ‘shifter’ handle.
This is strong and lightweight, and it features complex contours, which are partly for ergonomic reasons and partly decorative. “This was a fun but challenging project for us, as well as the engineers,” says Mr Harris. “It was machined using our five-axis VF-4, which allowed us to create the part in just two operations. We make about 20 a year; and like most parts on the car, they get ‘mileaged’ out and are replaced. Even with unstressed parts like this one, we don’t take chances; we don’t wait for them to fail.”
Among other Haas-machined components at Kannapolis-based SHR are the front-spindle uprights, which start out as forgings with the spindles pre-machined by the supplier. From here, SHR mills the remaining features, of which there are many; several parts are subsequently joined to the uprights by welding.
“After fabrication, an assembly will come back to us, and we’ll finish the entire machining in a single set-up without any compromise on precision or quality. Precision is the biggest challenge, because of the close tolerances and somewhat awkward shapes. We mount the part on the spindle snout in the trunnion on the VF-6TR, and we rotate it to hit all of the features in one set-up. It saves us a lot of time, and makes a really good component.”
Racing roots
NASCAR has its origins in the era of prohibition, when bootleggers would distribute their illicit liquor throughout the Appalachian region of the eastern and southern USA, using the fastest car-and-driver combinations they could find. The bootleggers used technical innovation to make their cars faster and more manoeuvrable; and when prohibition eventually ended, the innovators were having too much fun to simply call it a day. What grew subsequently was a sport that would eventually generate billions of dollars in annual revenues, and create a good living for tens of thousands of individuals and businesses.
Some five miles south of SHR, in Concord (a stone’s throw from the Charlotte Motor Speedway), is Hendrick Motor-sports (HMS). This company was formed in 1984 and has one of the most successful NASCAR teams, with 10 championships in the Sprint Cup series alone. Moreover, it was through HMS that Haas Automation originally came to this branch of motor-sport — initially as a sponsor and supplier of CNC machine tools. Today, SHR uses HMS engines and chassis, and the HMS machine shop on its 100-acre campus is populated almost entirely by Haas products.
HMS builds more than 550 engines per year, with many of these leased to other NASCAR teams. The various engine and chassis parts are made on a variety of Haas CNC machine tools, including VF-2 and VF-6 vertical machining centres, ES-5 horizontal machining centres and TL-25 turning centres with C axis, sub-spindles and live tooling. Larry Zentmeyer, engine shop co-ordinator, says: “We have four Haas ES-5 machines on campus to machine cylinder heads and intake manifolds. We also use them to re-work exhaust seats, and retrofit older designs with new ones. Moreover, each of our ES-5s is fitted with a Haas HRT210 rotary table and tailstock, to support the long parts. Each month, we machine around 12 sets — that is, 24 manifolds — which means the machines are always busy, but not so busy that we need multiple pallets or pallet changers.”
Castings from Chevrolet
HMS cylinder heads are also machined using the Haas ES-5 horizontals. These complex parts start life as semi-finished castings supplied by Chevrolet. “Enough material is left for us to add valve-train and rocker-stand features,” says Mr Zentmeyer. “There’s also plenty of material left for us to come in and port the exhausts and the intakes, and there is also some machining required in the combustion chamber. Basically, there is hardly a surface on the casting that we don’t machine in some way or form. Some machine operators have Siemens NX systems alongside the machines, where they prepare programs. The HMS engine shop also custom-fits its pistons to each cylinder block, using one of the VF-2s to do final machining work on the piston tops. This way, we can get the tolerances and fits exactly as we want. On average, we machine around 20 piston sets every week.”
As well as cylinder heads and pistons, HMS makes and supplies high-volume parts and components — such as alternator cages — to major companies such as Bosch. “Many parts for use in road vehicles are cast. We machine those parts from solid billets, so they’re stronger and more durable. If we used cast parts on the race cars, they wouldn’t last more than a lap or two, because of the temperatures and the vibration.”