MAINTENANCE

NOTE: New chain tends to stretch. Check the chain tension frequently and tension as required.

CAUTION:

A chain tensioned while warm may be too tight upon cooling. Check the “cold tension” before next use.

CHAIN MAINTENANCE

See Figures 51 and 52.

4.Keep the file level with the top plate of the tooth. Do not let the file dip or rock. See Figure 54.

5.Using light but firm pressure, stroke towards the front corner of the tooth. See Figure 55.

6.Lift the file away from the steel on each return stroke.

7.Put a few firm strokes on every tooth. File all-left hand cutters (A) in one direction. Then move to the other side and file the right-hand cutters (B) in the opposite direction. See

Figure 56.

8.Remove filings from the file with a wire brush.

CAUTION:

Check that the switch is in the STOP “ ” position before you work on the saw.

Use only a low-kick-back chain on this saw. This fast-cutting chain provides kick-back reduction when properly maintained.

For smooth and fast cutting, maintain the chain properly.

The chain requires sharpening when the wood chips are small and powdery, the chain must be forced through the wood during cutting, or the chain cuts to one side. During maintenance of the chain, consider the following:

■Improper filing angle of the side plate can increase the risk of a severe kick-back.

■Raker (depth gauge) clearance (A). See Figure 55.

1.Too low increases the potential for kick-back.

2.Not low enough decreases cutting ability.

■If the cutter teeth hit hard objects such as nails and stones, or are abraded by mud or sand on the wood, have the Homelite service dealer sharpen the chain.

NOTE: Inspect the drive sprocket for wear or damage when replacing the chain (B). If signs of wear or damage are present in the areas indicated, have the drive sprocket replaced by a Homelite service dealer. See Figure 56.

SHARPENING THE CUTTERS

See Figures 53 through 56.

PARTS OF A CUTTER

(A) Cutting Corner

(E)

Gullet

(B) Side Plate

(F)

Heel

(C)

Depth Gauge

(G)

Rivet hole

(D)

Toe

(H)

Top Plate

Be careful to file all cutters to the specified angles and to the same length, as fast cutting can only be obtained when all cutters are uniform.

1.Wear gloves for protection.

2.Tension the chain prior to sharpening.

NOTE: Refer to “Maintenance – Adjusting the Chain Tension” earlier in this manual.

3.Use a 5/32 in. (4 mm) diameter round file and holder. Do all your filing at the midpoint of the bar.

CAUTION:

A dull or improperly sharpened chain can cause excessive engine speed during cutting which may result in severe engine damage.

WARNING:

Improper chain sharpening increases the potential of kick-back.

WARNING:

Failure to replace or repair a damaged chain can cause serious injury.

WARNING:

The saw chain is very sharp. Always wear protective gloves when performing maintenance to the chain.

TOP PLATE FILING ANGLE

See Figure 57.

■(A) - CORRECT 30° – file holders are marked with guide marks to align file properly to produce correct top plate angle.

■(B) - LESS THAN 30° – for cross cutting.

■(C) - MORE THAN 30° – feathered edge dulls quickly.

SIDE PLATE ANGLE

See Figure 58.

■(D) - CORRECT 80o – Produced automatically if you use the correct diameter file in the file holder.

■(E) - HOOK – “Grabs” and dulls quickly, increases the potential of KICK-BACK.

Results from using a file with a diameter too small or a file held too low.

■(F) - BACKWARD SLOPE – Needs too much feed pressure, causes excessive wear to the bar and chain.

Results from using a file with a diameter too large or file held too high.

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Homelite UT74121D manual Chain Maintenance, Sharpening the Cutters, TOP Plate Filing Angle, Side Plate Angle
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UT74121D specifications

The Homelite UT74121D is a versatile and efficient string trimmer designed for homeowners and gardening enthusiasts who seek an effective solution for lawn maintenance. This machine excels at tackling overgrown grass, weeds, and edging tasks, offering performance and convenience.

One of the standout features of the Homelite UT74121D is its powerful 14-amp electric motor. This robust motor delivers consistent performance and ample cutting power, making it suitable for various landscaping tasks. Unlike gas-powered trimmers, the electric motor ensures quieter operation with zero emissions, making it an environmentally friendly choice.

The trimmer is equipped with a 17-inch cutting width, providing an expansive area for trimming, thus reducing the time needed to complete yard work. Featuring a dual-line feed system, the UT74121D allows for efficient cutting. The automatic line advance ensures that users can focus on their trimming without frequent interruptions to replace the line.

The lightweight design of the Homelite UT74121D contributes to its user-friendliness. Weighing in at just over 10 lbs, it is easy to maneuver, making it suitable for both large yards and tight spaces. The balanced design helps reduce user fatigue, allowing for longer periods of use without strain.

Another key characteristic of the UT74121D is the adjustable telescopic shaft. It can be extended or shortened to accommodate users of different heights, enhancing comfort and control during operation. This customizable feature enables better ergonomics and reduces the risk of back strain.

The Homelite UT74121D also incorporates a convenient pivoting head that allows for versatile trimming positions. This feature is particularly useful for edging alongside sidewalks and driveways, as well as for accessing hard-to-reach areas, making it a multi-functional tool for comprehensive yard work.

Moreover, the trimmer comes with a safety guard to protect the user from flying debris, promoting a safer mowing experience. The straightforward assembly and operation further appeal to users, with easy-to-follow instructions that make setup a breeze.

In conclusion, the Homelite UT74121D string trimmer is a practical and efficient tool for homeowners looking to maintain their lawns effectively. With its powerful motor, expansive cutting width, lightweight design, adjustable shaft, and safety features, this trimmer checks all the boxes for a reliable gardening companion. Whether you’re edging, trimming, or maintaining your yard, the UT74121D is designed to meet your landscaping needs with ease and efficiency.
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