Sewing Machine Knife Kit TF123/TF122 for Singer 14N654 & Brother

Sewing Machine Upper & Lower Knife Kit TF123/TF122

Keep your serger running at peak performance with this replacement upper and lower knife kit (TF123/TF122). Designed for popular home sewing and overlock machines including the Singer 14N654 and Brother 3034D, this kit gives you everything you need to restore crisp, clean fabric cutting in one convenient package. Made in Mainland China.

Why Choose This Knife Kit?

• Broad Compatibility: Fits Singer 14N654, Brother 3034D, and other models that use TF123/TF122 blade specifications — no guesswork required.
• Complete Kit: Includes both the upper knife (TF123) and lower knife (TF122) so you can replace both blades at once for balanced, even cutting performance.
• Durable Construction: Crafted from sturdy, long-lasting materials that stay sharp through extended use, ensuring smooth and consistent fabric trimming stitch after stitch.
• Easy Installation: Designed for a straightforward swap — even beginner sewists can replace the blades quickly and confidently, getting the machine back in action fast.
• Great Value: Buying both blades together in one kit is far more cost-effective than sourcing each part separately, making this an smart investment for any home sewing setup.

Kit Contents

• 1× Upper Knife (TF123)
• 1× Lower Knife (TF122)

Compatible Models (includes but not limited to)

• Singer 14N654
• Brother 3034D
• Other domestic overlock/serger machines using TF123/TF122 blades

Specifications

• Brand: HELTC
• Type: Upper & Lower Replacement Knife Set
• Compatible Use: Embroidery, overlocking, serging, general sewing
• Country of Origin: Made in Mainland China

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For more guidance on safe use of cutting tools and sewing accessories, visit the U.S. Consumer Product Safety Commission (CPSC) for general product safety information.

Learn more: Notions (sewing)

Frequently Asked Questions

Q: Which sewing machine models is this upper and lower knife kit compatible with?

A: This TF123/TF122 knife kit is specifically designed for the Singer 14N654 and Brother 3034D serger/overlock machines. It may also be compatible with other domestic overlock machines that use TF123 upper and TF122 lower blade specifications — check your machine's manual to confirm blade model numbers before ordering.

Q: Is this knife kit easy to install at home without professional help?

A: Yes! This kit is designed for straightforward at-home installation. The replacement blades are engineered to fit precisely, and most users — including beginners — can complete the swap quickly using basic tools. Always refer to your sewing machine's manual for step-by-step blade replacement guidance.

Q: How often should I replace the upper and lower knives on my serger?

A: Blade replacement frequency depends on usage intensity and the types of fabric you sew. As a general rule, if you notice the fabric edges becoming ragged, frayed, or unevenly trimmed, it's time to replace the blades. Having a spare TF123/TF122 kit on hand ensures you're never caught mid-project with dull blades.