1. Introduction The motor base (see Figure 1) is a key structural component of the ZN50C vibrator (a product that won the National Silver Medal), a product of our school's factory. It requires a strict positional relationship with the end cover (containing bearings) and the motor stator. The machining of the inner hole, the end stops, and the guide holes are critical processes affecting product quality. Previously, this machining was completed in two clamping operations on a conventional lathe, resulting in high labor intensity, significant centrifugal force during the workpiece's main rotational motion, severe chip splashing, and low machining accuracy and production efficiency. Therefore, we designed a device for machining on a conventional lathe, enabling the inner hole, end guide holes, stops, and end faces of the base to be machined in a single workpiece clamping operation. This not only ensures the dimensional and positional accuracy of the workpiece but also overcomes a series of drawbacks associated with the previous two-clamping method. This device requires minimal modification to the machine tool, easily restores the lathe's functionality, and has proven to be very effective in use. [align=center]Figure 1 Motor base 1. Tie rod 2. Spindle 3. Front boring head 4. Boring tool 1 5. Boring tool 2 6. Sliding sleeve 1 7. Transmission rod 8. Sliding sleeve 2 9. Boring tool 5 10. Rear boring head 11. Boring tool 7 12. Tailstock 13. Bearing 14. Outer sleeve 15, 16. End cover 17. Boring tool 6 18. Transmission pin 2 19. Transmission pin 1 20. Boring tool 4 21. Boring rod 22. Boring tool[/align] 2. Machining device design The motor base machining device is divided into the following five parts, as shown in Figure 1. 2.1 Front boring head The front boring head is mounted on the spindle of a lathe (such as C6132), and a boring tool 1 for turning the left end face of the machine base is installed. The boring tool is locked with screws. 2.2 Boring Bar The boring bar is installed in the Morse taper hole of the spindle and tightened by a tie rod. Two boring tools (boring tool 2 and boring tool 3) are installed in a tool slot at the left end of the boring bar. Their axial position is guaranteed by the dimensions of the boring tools themselves, and their radial position is guaranteed by the boring machine tool setting tool (as shown in Figure 2). Boring tools 1, 2, and 3 are used to bore the left end face of the machine base, the guide hole, and the stop, respectively. A boring tool 4 for boring the inner hole of the machine base is installed in a tool slot at the right end of the boring bar. Its radial position is also guaranteed by the boring machine tool setting tool. A transmission screw and bushing are installed on the stepped shaft at the right end of the boring bar, transmitting its main rotational motion to the rear boring head via a transmission rod. [align=center]Figure 2 1. Screw 2. Bracket 3. Boring rod 4. Screw 5. Tool head 6. V-block 7. Depth micrometer[/align] 2.3 Transmission rod Each end of the transmission rod is equipped with a transmission pin. When the rear boring head is needed to bore the right side of the machine base, the transmission rod is placed between the boring rod and the rear boring head. The nut at the top of the screw is loosened, and the sliding sleeves on the boring rod and the rear boring head are fitted into the transmission rod. After rotating a certain angle, the transmission pin falls into the groove of the sliding sleeve, and the sliding sleeve is locked with the nut. The main rotational motion of the boring rod is transmitted to the rear boring head through the sliding sleeve, transmission pin, and transmission rod. When the workpiece is finished, the workpiece is moved to the left end of the boring rod, the sliding sleeve slides back to its original position, the transmission rod is removed, and the workpiece is moved back to the original transmission rod position (the length of the transmission rod is about 5mm longer than the workpiece). The workpiece can be loaded and unloaded very conveniently here. 2.4 Rear Boring Head The rear boring head is obtained by modifying the lathe tailstock. The sleeve of the lathe tailstock is removed, and the rear boring head assembly is installed. Three boring tools are installed at the front end of the rear boring head, used to machine the guide hole, stop, and right end face of the machine base, respectively. A pair of radial thrust ball bearings are installed at the rear end and sealed with an end cover. When installing the rear boring head, ensure that the coaxiality between the rear boring head axis and the front boring head axis is no greater than 0.015. 2.5 Machine Base Fixture The machine base fixture is installed on the lathe's intermediate slide (the original small slide and tool post are removed). The fixture base flange mates with the lathe being used, and the cutting feed motion is achieved by the movement of the saddle. The specific structure of the fixture is designed according to different motor and machine base structures. 3. Workpiece Machining Process 1) As shown in Figure 1, install the workpiece between the boring bar and the rear boring head. Feed the workpiece to the left to machine the inner hole of the machine base. Continue feeding to the left to machine the guide hole, stop, and left end face of the workpiece. 2) Stop the machine and install the transmission rod. 3) Feed the workpiece to the right. At this time, the rotational motion of the spindle is transmitted to the rear boring head through the boring bar and transmission rod to machine the guide hole, stop, and right end face of the workpiece. After machining, the workpiece is returned to the boring bar. 4) Stop the machine, remove the transmission rod, move the workpiece to the original transmission rod position, unload the machined workpiece, and install the workpiece to be machined. 4. Boring Machine Tool Setting Tool The boring machine tool setting tool shown in Figure 2 allows for convenient and precise positioning of the boring head. The method of use is as follows: Place the V-block 6 on the boring bar 3, and use screw 1 to fix the bracket 2 and V-block 6 to the boring bar. The boring head 5 is slightly larger than the required size. Then, using a depth micrometer 7 and a top cutter head 5, the tool tip is forced to retract to the required position and locked with screw 4. 5. Design Features of the Machining Device This machining device, by changing the workpiece rotation to tool rotation, has low centrifugal force, easy chip handling, and convenient workpiece loading and unloading, ensuring machining quality and improving production efficiency. Lathe modification is simple; to restore lathe function, simply remove the machining device and reinstall the original lathe components. It is very suitable for machining small and medium-sized motor bases.