MRO Today



MRO Today

'Bobtail' truck assembly shortened with compact drill unit

Mid-Michigan builder puts propane trucks together now an hour or more faster than before thanks to a low profile magnetic drill that works in all the tight places

Even though it’s a relatively new company, Signature Truck Systems Inc., founded by owner and president Joe Volk a little more than two years ago, appears to be doing things right. 

The firm, located in Clio, Mich., is on a steady growth track in its production, service and as a government certified testing facility of specialized vehicles for the propane gas industry. This includes large, bulk transport tanker trailers, and the shorter, unitized “bobtail” trucks that make gas deliveries to residential and smaller size commercial facilities. Their bobtail vehicles are outfitted complete, starting with a customer specified chassis, then with mounting of the tank and rear deck, all plumbing, electrical, pneumatic and pumping systems, meter calibration, tests certifications, even the customer’s logo. Each Signature truck is ready to immediately deliver gas when it leaves the assembly facility.

One of the things they’re doing right is quality. Considering the rigid safety guidelines and standards that must be strictly adhered to for these vehicles, Signature’s number one priority is on quality of materials used, in workmanship and in their test and verification procedures. 

A second area where they’re gaining a competitive edge without sacrificing safety or quality is in the streamlining of production methods, and in particular the tools being used to help shorten build times, according to Al Avram, operations manager. One such tool is the new HMD100 Portable Magnetic Drill from Hougen Manufacturing Inc. Its ultra-low profile and compact size allows truck builders like Signature to access and drill holes in chassis areas where previously employed frame drills were awkward to maneuver and too slow in use. Or worse, the drills required the truck frame to be raised, allowing the suspension to drop the wheels or complete removal of the tires and rims in order to gain access if drilling was necessary in the wheel well area.

“Since we acquired and began using Hougen’s magnetic drill, we’ve been able to save about one hour in the drilling of the 18 to 24 holes necessary for assembling one of our typical truck models, time we previously wasted using the frame drill," said Avram.  "For more complex build projects, we can save two or more hours.”

“Most of the time savings, but not all, is achieved through our technicians’ ability to move and position the magnetic drill fast,” continued Avram. “Compared to the frame drill, the HMD100 is like ‘plug & play’ hole making. The drill also fits between the wheel and frame, so there’s no need to lift the chassis with a fork lift or jacks to drill in the wheel well. We also save time in the actual drilling cycle. I’d estimate that each hole, typically 5/8-inch diameter through 3/8-inch thick high tensile steel frame members, is drilled twice as fast using the magnetic drill equipped with it’s Rotabroach 17,000-series Quick Change cutters instead of a standard twist drill bit.”

In using a conventional frame drill, Mr. Avram explained, its size and maneuverability are its biggest drawbacks. A large drill head is mounted on a stand with a base measuring approximately 2 feet by 3 feet, on casters. Drill bits can be 2 to 3 feet long, and moving the unit around requires lots of space plus everything on the floor — extension cords, compressor hoses, tools — need to be cleared away for the drill to roll around. Then, positioning and securing the frame drill by wrapping chains around the truck frame takes up more valuable time.

By comparison, he points out that the Hougen magnetic drill only requires that the operator position the drill over the hole location, push one button to energize its electromagnetic base, thus securing it to the frame, then push a second button to start spindle rotation and pull on one of two feed handles. Since the drill weights just 20 pounds, it is highly portable and easy to carry, position accurately, and operate.

The HMD100 Portable Magnetic Drill was developed in response to the distinct needs of the specialty truck frame and chassis builder where traditional horizontal frame drilling equipment has been the standard, although today, the magnetic drill’s uses also include plant maintenance, general fabrication and on-site building projects where access to hole locations is restricted or severely limited. It features a new Quick Release tool mounting system which does not require any tools to change out cutters, and a height of just 6-1/2 inches. In spite of the drill’s minimal size and weight, it provides 5/8-inch thru 1 1/16-inches diameter and 3/4-inch depth of cut hole capacity while its powerful magnetic base, measuring 4 inches x 7 inches, offers secure holding with a 1,283 pounds dead lift rating on 3/8-inch plate. The HMD100 model’s 6-1/2-inch height easily fits in wheel wells and other locations along frame rails, cross members, support braces and bumpers — ideal for most drilling of mounting holes plus access and routing holes for electrical, hydraulic or pneumatic equipment.

The HMD100 operates from a standard 115 volt power source and features two feed handles, one on each side and rear-positioned controls to optimize ergonomic operation. A mechanical pull-and-twist pin lock allows these handles to double as a stationary carrying handhold, while simple thread mounting permits one handle to be quickly removed if extra clearance is required. With both feed handles removed, a hex head drive allows the use of a socket wrench for ratcheting the feed mechanism when drilling in even tighter, more confined spaces. Controls include separate magnet engage/disengage and spindle motor on/off switches —for safety, the motor switch must be continuously depressed during operation.

The HMD100 also has a rigid quill feed which prevents tool vibration, eliminates gibs and slide/way adjustments, maintenance, and provides a constant low profile.

In addition, the HMD100 has been given a new arbor design featuring bayonet-style twist and lock tool mounting for fast changeover. Complementing this feature, Hougen also developed the "17,000-Series" Rotabroach Annular Cutters with Quick Release shanks. Because they are hollow and have Hougen's unique and time-proven tooth geometry, the "17,000-Series" cutters outperform conventional holemaking tools (twist drills, spade drills, hole saws), providing longer service life. A 3/4” diameter cutter, for example, will drill through stacked 1/4” plate, 1/2” thickness, in 40 seconds. The cutters are made from M42 tool steel, heat-treated and precision ground, and provided as standard with an exclusive tooth geometry that allows cutting holes through stacked or doubled-up materials as well as on single plate applications.

And, with regards to performance, at Signature Truck Systems, the HMD100's performance is spreading. 

“More and more, not only at our assembly stations, but now in the fabrication areas, you’ll see technicians ‘grab and run’ with the drill to use it on their particular application because of its time savings, ease of use and convenience,” said Avram. 

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