Jasper Fisher 
Rexel Motor Repair 
Alton, Illinois 
Technical Education Committee Member 

Though it is unlikely a typical EASA member firm can achieve OEM (Original Equipment Manufacturer) economies of scale, we can strive to improve safety and working conditions, improve quality and increase labor efficiency thereby enhancing earnings. 

This article shares tips for building several special tools and fixtures, and it identifies one commercially avail­able tool to help us achieve safety and quality goals while improving our productivity. 
After hearing complaints about the purchase cost for the last two sets of custom heat-treated long taper pinion removal wedges, our ma­chine shop staff designed and built a fixture for tapering “brake die” rectangular steel (Figure 1).

The principal design elements and the material we use are: 

• 3/4” x2” x28” (19x51x710 mm) hardened rectangular steel bar, ground finish(decarbfree) 4140 / 4142 pre-heat treated, shortened from the 36” (915 mm) purchase length to 28” (710 mm). 
• Fixture surface prepared to approximately 0.270 inch (6.9 mm) taper per foot (305 mm) (Figure 2). 
• Low-grip “toe-edge” clamps to secure the brake die bars to the fixture (Figure 3). 
• This material remains stable (doesn’t bow) after the bars are profiled on the fixture.

Sets of long taper wedges will save time and preserve the dimen­sional tolerance and hardness of shaft mounted gears, pinions, etc. which are received without adequate provision to facilitate removal. 

“Chicken Sticks” 
What seems like eons ago, when faced with the challenges of safely blocking under frame feet positioned higher than the bottom (belly) of the frames, a clever mechanic crafted a heavy wall pipe assembled with a suit­able stud secured to an end cap plate with all parts welded for stability and strength. This was also done when it was necessary to clear leads or con­nection bus assemblies, especially when the frame feet are not coplanar, as in ship propulsion motors. Our technicians fondly call this solution “chicken sticks” (Figure 4) as they no doubt share Rhode Island Red chicken morphology. 

Robust over-design is much desired when crafting chicken sticks. We use heavy wall pipe, end caps of nominally greater thickness than the pipe wall, and Grade 5 fasteners as the studs. Care must be taken to ensure that sticks are securely bolted to the feet and the stick-mounted machine is positioned on a level, load-rated floor surface with verification that the center of gravity of the machine does not pose a tip hazard before removing the lift rigging. 

An additional benefit of having chicken sticks available is the ability to raise a large machine to a sufficient height to fa­cilitate ease of installing and seating brushes, taping leads and bus interconnections, etc. Your knees will most certainly appreciate this ergonomic strategy. 

NEMA MG 1-2003 Section 1, Part 4, sets forth alternating current foot-mounted machine mounting di­mensions and tolerances. Paragraph 4.15 in the same section sets forth a “Method To Check Coplanarity Of Feet Of Fully Assembled Motors.” In those circumstances when a tool room Grade B granite block of sufficient size is not readily available, an alternate method not spoken to in Paragraph4.15 is to use a tool steel precision straightedge with beveled edge.

NOTE: We pur­chased our straightedge, which is 72” (1,830 mm) L x 3-5/32” (80.2 mm) W x 9/32” (7.1 mm) thick, from a well known national industrial supplier. The straightedge has a hole in one end for hanging hook storage that ensures stability (Figure 5). While the frame is safely and symmetrically suspended and positioned, we use feeler gauges (Figure 6) to check for coplanarity of the feet: left to right, front to back, and then across both diagonals to ensure they are within 0.015” (0.38 mm) (Figure 7). 

we needed to install a 1-3/4” (44 mm) width keyway to replace one worn beyond the original 1-1/2” (38 mm). We turned an adaptor to mount on a suitably sized angle plate which mated the head of our Bridgeport® knee mill (Figure 8). Two parallel machining passes and the repair was accurately and expeditiously completed, which was a profit opportunity exploited (Figure 9)! 

Hoist rings pivot and swivel to compensate for pitch, roll, and sway when lifting awkward, unbalanced loads. We find them most efficacious when used to upend or lay down rotors, armatures and frames. When practical, if the shaft extension is not already threaded, we tap a hole, sized proportional to the rotor weight. Trac­tion and mill motor armatures, which have robust threaded shaft extensions for pinion nut mounting, are best handled using hoist rings screwed into a custom nut assembly (Figure 10) which fully seats against the face of the shaft extension. Using suitably sized hoist rings, most rotors, armatures and frames can be safely re-positioned (Figures 11-13). Homemade bails and forged eyebolts (plain or shouldered) are not as reliable and safe as hoist rings when laying over any heavier motor components. 

Learning From Others 
Speaking of mill motors, I am reminded of a clever solution placed in our hands by our local sheet metal journeyman guru (for a modest fee of course). When challenged to efficiently remove shaft nuts from deep dished brake wheels, we sought counsel with our trusted, friendly, sheet metal man. His solution was to fabricate sockets using his precision plasma cutting system. Note in the photos on page 11 (Figures 14-15) the custom sockets have a hex cutout welded onto both ends of the cylinder which stabilizes the torque tube. We use a railroad or other large bar through the intersecting drive holes. This is a great example of the benefits of networking, peer groups, etc.! 

These machine shop fixture designs were shared and/or conceived in our plant by masterful journeyman machinists, tool and die makers, and techni­cians we have had the good fortune to be teamed with over the span of some 34 years. 

In conclusion, many EASA mem­bers depend on their networks of allies, colleagues, and peers when challenges arise. Enlarging the scope by shar­ing trade tidbits to a larger audience (such as in EASA CURRENTS) yields tremendous satisfaction rewards. I en­courage you to share your own insights and trade tips with EASA’s profes­sional staff so that our whole industry is thereby strengthened. 

Categories: Service center equipment

Tags: Service center equipment Tools

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