Link: Product Reassembly Plan

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Contents

Introduction

The Homelite® VersaTool™ line trimmer serves as an effective design that exhibits efficient machinery, allowing for the product to be assembled with minimal effort when considering the components involved in such a process. While necessitating a moderate familiarity with technical knowledge and terminology, reassembling this product proves rather simple for the mechanically inclined by following this step-by-step guide. Akin to the dissection plan provided in Gate 2, the reassembly procedure follows the same format, involves precisely the same tools, and contains an almost identical difficulty scale; indeed, a mere reversal of the steps of disassembly and amendments to the corresponding difficulty rating for those steps, amount to the only readily apparent differences between the two plans. Ranging from 1-5, and centered around the same three primary components as the dissection plan, the scale of difficulty is delimited thus:

  1. Time: How long does it take to perform the step?
  2. Tools required: Are the tools required for the step uncommon, or inaccessible to whatever extent, for the typical homeowner?
  3. Component visibility and technical knowledge: Does the step require mechanical knowledge or experience to be performed, and is the fastener visible or easily applied to the threaded hole?

Steps labeled with the highest difficulty rating (5) meet the entire aforementioned criterion at a high level; steps receiving the highest difficulty rating exacted substantial effort and time from the reassembly technicians of the group. The scale is further analyzed later in this section.


Tools Required

Note: Asterisk (*) denotes the rarity of the tool such that it registers a high rating on the scale of difficulty for the typical homeowner.

  1. Torque wrench size T25 (use straight-shafted, screwdriver grip)*
  2. Socket size 3/8
  3. Socket size 5/8 (deep)
  4. Socket size 7/16
  5. Adjustable Channel locks
  6. Holding pin (Straight-shafted torque wrench will suffice)
  7. A manual press machine*
  8. Needle-nosed pliers



Scale of Difficulty

The scale of difficulty follows the three main criteria noted above, along with several other minor attributes. Throughout the reassembly process, each step is accorded a difficulty rating and a brief rationale behind that rating. This scale is defined as follows:

  1. The component in question is easily configured or mounted to the other component.
    • A very common household tool, or even no tool, is required.
    • The step necessitates less than a minute to be performed, given availability of appropriate tool(s).

  2. The step satisfies all aspects of a “1”, except the tool required may prove uncommon for the typical homeowner.
    • The need for more than one tool may arise so as to perform the step as instructed.

  3. To implement the step of reassembly, some mechanical or technical knowledge is required (e.g., in the case of a spring-loaded part).
    • Also, the step necessitates investment of a considerable amount of time for the typical homeowner.

  4. Reassembling the component meets the criteria of a “3”, and involves certain alignments and/or re-alignments (e.g., a gear can be inserted one way only).

  5. Step for reassembly requires a spectrum of knowledge beyond that of the average homeowner.
    • The proper tools necessitated by the reassembly are seldom part of the standard technical equipment of an ordinary household.
    • The typical homeowner may damage the product by utilizing improper, or entirely inapplicable, equipment and technique to attach, mount, fasten, or configure a particular component.
    • Technical skill is a prerequisite to perform reassembly, which may entail limited visibility of the component being mounted, fastened, or configured, and the internal structure thereof that may affect neighboring or interdependent components.



Procedure for Reassembly

Note: On the images below, red circles enclosing numbers, which are arbitrary and thus bear no relevance to any particular step corresponding to the exploded views, denote the region of the product or component thereof referred to in its respective step of reassembly. Please disregard, in the interest of obviating confusion, other annotations on the images as they are impertinent to the corresponding step of reassembly.


Images are courtesy of the Homelite®-published "Parts List", accessed via the public domain. For references, please scroll to the bottom of this page. [1]


Table 4.1: Procedure for Reassembly
Step Number Procedure Tools Difficulty (1-5) Image


Engine Assembly

1 Insert (2) bearings and rubber seal into the hole located in the short block, where the engine shaft would protrude.

Part contains tolerance of about .001 of an inch.
Requires a manual press machine, or something of similar machinery or function. 5: Tool required is exceedingly rare for a common household.

This step should be performed by someone with proper equipment and technical qualification (e.g., machine shop personnel).
Figure 4.1: The Engine Shaft connected to the Short Block is highlighted. Click to view a higher resolution of the image.
2 Insert engine shaft into bearings, starting from the side of the crank case.

Part contains tolerance of about .001 of an inch.
Requires a manual press machine, or something of similar machinery or function. 5: Tool required is exceedingly rare for the typical homeowner.

This step should be performed by someone with proper equipment and technical competency (e.g., machine shop personnel).
Figure 4.2: The image refers to the same as in the one above.
3 Slide the open end of the connecting rod onto the shaft peg situated inside the crank case.

Attach piston and piston ring, if not assembled.
No tools required. 1: Components mounted manually.
Figure 4.3: The Piston Ring (3), as well as the Piston & Rod Assembly (2), are highlighted. Click to view a higher resolution of the image.
4 Place engine head on top of short block, sliding in the piston.

Fasten (3) fasteners which adjoin the engine head to the short block.

Fasteners are located underneath the head, needing to be screwed in “upside down.”
Requires torque wrench (T25). 2: Tool required is somewhat rare.
Figure 4.4: A Screw (Sems) (9) and the encasing, or engine head (4), for the Cylinder Assembly are highlighted. Click to view a higher resolution of the image.
5 Attach crankcase cover assembly to crankcase located at the rear of the engine assembly.

Fasten the (4) screws to attach the component and its gasket.
Requires torque wrench (T25). 2: Tool required is somewhat rare.
Figure 4.5: A Screw (Sems) (12) for the Crankcase Cover Assembly is highlighted. Click to view a higher resolution of the image.
6 Screw in spark plug to the top of the engine head. Requires deep socket size 5/8. 1: Part is easily accessible.

Step is performed in less than 60 seconds.
Figure 4.6: The Spark Plug (3) raised above the ribbed piston encasing is highlighted. Click to view a higher resolution of the image.
7 Attach ignition kit (magneto) to the front of the engine assembly by fastening the (2) screws and connecting the terminal to the top of spark plug. Requires torque wrench (T25). 2: Tool required is somewhat rare.
Figure 4.7: The Screws (Taptite) and the Terminal (1) and Cover (2) of the Ignition Kit are highlighted. Click to view a higher resolution of the image.
8 Attach muffler assembly, and gasket, to the engine head via the (2) fasteners, which go through the muffler and are located to the right when viewing the face of the muffler. Requires torque wrench (T25). 2: Tool is somewhat rare.
Figure 4.8: The Gasket (3) and Screws (Truss hd.) (4) of the Muffler Assembly are highlighted. Click to view a higher resolution of the image.
9 Fasten (2) screws connecting the heat dam to the engine head, which is located on the side opposite that of the muffler. Requires torque wrench (T25). 2: Tool required is somewhat rare.
Figure 4.9: The Gasket (1) and Screws (Sems) (4) of the Heat Dam are highlighted. Click to view a higher resolution of the image.
10 Slide carburetor onto screw pegs that come out of the heat dam, and slide on the rear of the air filter case.

Fasten (2) hex head nuts on the two pegs.
Requires socket size 3/8. 1: Tool required is very common, and parts are easily accessible.
Figure 4.10: The Gasket (5) to the Carburetor and Hex nuts (10) securing the air filter kit to the carburetor are highlighted. Click to view a higher resolution of the image.
11 Insert air filter into the back piece of the case.

Slide hinges of the front piece of the air filter case into position, and clip in the top.
No tools required. 1: Only manual input necessary.
Figure 4.11: The tab of the removable cap of the air filter is highlighted. Click to view a higher resolution of the image.
12 Attach fuel tank to the back of engine assembly in between the short block and crank case cover (apply force).

Attach fuel lines to carburetor tubes, left line to left tube, and the same for the right.
No tools required. 2: Step requires some amount of force applied by the technician.
Figure 4.12: The Fuel Tank Assembly (F) and its component Fuel Lines (8 and 9) are highlighted. Click to view a higher resolution of the image.
13 Slide flywheel onto the engine shaft.

Parts may contain small tolerance and may require an arbitrary tool for leverage.
No tools required. 1: No tools necessary, but subject to a “2” if an implement proves necessary for leverage.
Figure 4.13: The Flywheel (6), or Rotor, is highlighted. Click to view a higher resolution of the image.
14 Attach front plastic covering via the (4) fasteners situated on the front. Requires torque wrench (T25). 2: Tool is somewhat rare.
Figure 4.14: The Starter Assembly. Click to view a higher resolution of the image.
15 Attach the clutch, and configure the drum kit assembly, to the front end of engine shaft via a fastener located down the hollow tube of the clutch. Requires torque wrench (T25). 4: Requires an alignment for the fastener (not visible, done by “touch”).
Figure 4.15: Clutch and Drum Kit (8) are highlighted. Click to view a higher resolution of the image.
16 Attach rear plastic cover via the (2) fasteners which screw into the front cover. Requires torque wrench (T25). 2: Tool required is somewhat rare.
Figure 4.16: Two Plastite fasteners (21) on opposite sides of the Rear Housing (20) are highlighted. Click to view a higher resolution of the image.


Line Spool/Guard Assembly

17 Assemble the gear head by connecting the two halves via (4) fasteners located on the side.

While performing this, insert the flexible drive-shaft into the square hole located inside the gear head casing.
Requires socket size 7/16, and a torque wrench (T25). 3: A time-consuming and somewhat technically rigorous process, owing to the multiplicity of fasteners and trying not “to do two things at once.”
Figure 4.17: The Taptite Hex Hd. Screw (12) and the Hex Hd. Screw (13) of the Gear Head assembly are highlighted. Click to view a higher resolution of the image.
18 Attach the grass deflection shield to the gear head assembly using (5) fasteners located on the bottom of the gear head assembly. Requires torque wrench (T25). 3: Step may require several minutes to be performed competently, primarily owing to the number of fasteners present.
Figure 4.18: The Gear Head (11), Grass Deflector (14), and Taptite Hex Hd. Screw (12) are highlighted. Click to view a higher resolution of the image.
19 Slide the thick geared washer onto the gear shaft.

If one rotates this washer a cut-out square groove can be seen.

The bottom part of the gear head assembly also has a similar cut-out hole.

Align these two holes and insert a holding pin (something thin enough to fit, but strong enough to withstand force; torque wrench, T25, should suffice.)

While keeping the holding pin in, screw on the line spool by hand.
A pair of channel locks may be necessary to fasten the line spool firmly. 4: Step requires some technical knowledge in order to determine how to have it carried out.

Also, step may consume several minutes to perform, as the holes are not readily apparent.
Figure 4.19: The Gear Head (11), Grass Deflector (14), and Flanged Washer (18) are all highlighted. Additionally, the direction in which the Holding Pin is applied and in which the Stringhead rotates are also indicated by red arrows. Click to view a higher resolution of the image.


Final Product Assembly

20 Insert the long flexible drive-shaft into the hollow end of the clutch, which is attached to the engine assembly.

Insert (4) fasteners from the front of the throttle control into the front plastic covering of the engine assembly.
Requires torque wrench (T25). 2: Tool required is somewhat rare.
Figure 4.20: Two Taptite fasteners (27) on opposing sides are highlighted. Click to view a higher resolution of the image.



Concluding Remarks and Additional Recommendations

Overall, the complete reassembly of the Homelite® VersaTool™ line trimmer in question involves minimal exertion or technical background. After dissecting the product and becoming familiar with how the components interact, it made for a quick and comparatively hassle-free reassembly. Indeed, the duration of the reassembly equaled to approximately one-half that of the disassembly, which is detailed in Gate 2.

Moreover, reassembly technicians had developed an adequate understanding of the relative positioning and location of components during the original product dissection, thus enabling reassembly of the product in its entirety. Further, the same standard of tools used to dissect the product were also involved in its reassembly.

Although the lack of appropriate facilities and transportation to secure a fuel source precluded the group from assessing whether the product operates or functions per design, reassembly technicians did conduct a “spark test,” thereby confirming that the spark plug and ignition kit provide a spark. However, the spark manifested during the spark test constitutes merely a marginal portion of what is needed for the product to function.

Bearing the foregoing in mind, the product's design does not inspire, beyond the revisions addressed in Gate 3, any additional adjustments to either its configuration or its functionality. In light of potential increases in costs and the introducing of complexities in the design process, any auxiliary design revisions appended to the list of those considered earlier would only result in detriment to the marketable image, competitive retail, and efficient manufacture of the line trimmer.

To access further information relevant to Homelite® products and the Homelite® brand in general, please direct your browser to the link noted below in the "References to Supplementary Material". [2]


References to Supplementary Material

[1] Web link to "Parts List" released to the public domain under the auspices of Homelite®. <http://dl.owneriq.net/c/cbf6c17d-6a3d-4204-b67d-144253fdccd7.pdf.>

[2] Online Home Page of Homelite®. <http://www.homelite.com/>


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Reverse Engineering Team Project: Homelite® VersaTool™ Line Trimmer (Group 29)