Fixing Kenmore 385 Jamming: Bobbins, Burrs, and Thread Explained

· EmbroideryHoop
Fixing Kenmore 385 Jamming: Bobbins, Burrs, and Thread Explained
This comprehensive guide, drawn from Randy's Sewing Machine Man tutorial, helps Kenmore 385 and similar Janome-type owners eliminate persistent jamming. You'll learn how to identify whether a metal bobbin or rough hook surface is the culprit, how to polish out tiny burrs, and why 'All-Purpose Dual Duty' thread is the right match for these machines.

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Table of Contents
  1. Introduction to the Kenmore 385 and Common Jamming Issues
  2. The Bobbin Dilemma: Plastic vs. Metal and Magnet Interaction
  3. Inspecting and Smoothing Burrs: Hook and Presser Foot
  4. Thread Matters: Understanding the Thread Gap and Proper Thread Selection
  5. Careful Reassembly and Threading
  6. Final Checks for Jam-Free Sewing

Introduction to the Kenmore 385 and Common Jamming Issues

Kenmore 385 machines, built on a Janome-type platform, feature a drop-in bobbin system that’s usually reliable until a small oversight turns it stubborn. Owners often discover the culprit is either the wrong bobbin material or hidden burrs under the needle plate.

Close-up needle presser foot sewing blue fabric
The machine completing a line of stitches after fixing jamming.

Identifying a Kenmore 385 (Janome Type) Machine

Its front drop-in bobbin design and magnetic base distinguish it from vertical-load models. If your plate lifts straight up and the bobbin sits beneath a clear cover, this guide applies to you.

Recognizing the Symptoms of Jamming

Uneven tension, nests of thread underneath, or the “tap-tap” of a misaligned hook all signal a maintenance call. Checking bobbin type and rough surfaces should be your first move.

Removing needle plate screw
Disassembly begins by removing the needle plate screw.

The Bobbin Dilemma: Plastic vs. Metal and Magnet Interaction

One of Randy’s biggest reveals is that the Kenmore 385’s bobbin chamber hides a magnet designed to hold the case steady.

Needle plate lifted revealing bobbin area
Access to the bobbin case allows deeper inspection.

This tiny magnet demands a non-reactive (plastic) bobbin.

Why Plastic Bobbins are Crucial for Magnetic Housings

Plastic bobbins are inert—they don’t stick. Metal bobbins, however, cling to the magnet, warping tension and leading to inconsistent stitches.

Finger pointing to magnet under bobbin case
The magnet that holds the bobbin case in place—why plastic bobbins are essential.
⚠️ Using a metal bobbin in this model won’t necessarily jam it immediately, but your tension will drift unpredictably.

How Metal Bobbins Disrupt Tension

When the magnetic field tugs a steel bobbin, it pulls against the thread’s natural movement. Over time, this imbalance compounds with vibration and causes skipped stitches or loops.

Plastic bobbin case showing magnet effect
The plastic bobbin remains stable and unaffected by the magnet.
💡 Always verify your replacement bobbins are lightweight plastic like the class 15 type Randy recommends.
Metal bobbin attracted to magnet
A metal bobbin reacts to the magnet, disturbing tension.

For anyone exploring advanced accessories later, consider how specialized settings—such as magnetic hoops for embroidery machines—also depend on balanced tension, even in embroidery contexts.


Inspecting and Smoothing Burrs: Hook and Presser Foot

Even with the right bobbin, needle impacts can scar your machine’s hook or foot, leaving microscopic burrs. These tiny ridges can snag the thread and cause minute tangles that snowball into jams.

Finger pointing to burrs on hook
Burrs from needle deflection can cause thread snags.

Locating Needle Impact Burrs on the Hook

After removing the needle plate, run your fingertip around the hook’s circumference. Any snag—no matter how faint—needs attention. Burrs are most common where the needle meets the hook.

Filing and Polishing Rough Edges on the Hook and Presser Foot

Use a fine file or emery paper to gently level the raised areas, then polish with crocus cloth.

Using emery paper to smooth hook
Emery paper smooths raised burrs along the hook circumference.

Randy emphasizes that depressions are harmless—it’s the raised metal that catches thread. The same applies to the back edge of the presser foot.

✅ After smoothing, your finger should glide without hesitation across every edge.

From the comments: One viewer confirmed that switching to a diamond file with light touch solved snag issues on the non-metal bobbin case. Another found a burr underneath the throat plate—a reminder to inspect hidden spots carefully.

If you enjoy tuning machines at this precision, you’d appreciate the accuracy offered by magnetic embroidery hoop systems, which hold fabric steady just as a smooth hook keeps tension even.


Thread Matters: Understanding the Thread Gap and Proper Thread Selection

Every sewing machine has a “thread gap”—the distance between the hook and the spring that lets the thread pass freely. On the Kenmore 385, this gap is calibrated for one thing: All-Purpose Dual Duty thread.

Finger pointing to thread gap
Identifying the thread gap spring in the bobbin area.

The Function of the Thread Gap and Spring

As the handwheel turns, thread sweeps through the small opening beside the bobbin case spring. If your thread is thicker, it binds here and flips the bobbin case upward, starting the dreaded jam.

Distinguishing ‘All-Purpose Dual Duty’ from Specialty Threads

Randy demonstrates the difference between everyday all-purpose spools and thicker quilting or “Buttons, Carpets & Crafts” types.

Spool of quilting thread
Hand Quilting thread shown as an incorrect, too-thick option.

If the spool’s label is gone, test by twisting the filament—Dual Duty spins smoothly and stays tight.

Spool labeled Buttons Carpets & Crafts
Another thread that’s too heavy for the thread gap.
⚠️ Any thread labeled “Hand Quilting” or “Top Stitch” is likely too thick, approximately twice the allowable diameter.

For best results, use Dual Duty All-Purpose—thickness near five-thousandths of an inch.

Spool labeled Dual Duty All-Purpose thread
The correct all-purpose dual-duty thread for this machine.

From the community feedback, many sewers realized this simple thread swap instantly fixed long-standing looping. One viewer remarked how the all-purpose switch “made the bobbin problems vanish.”

For embroiderers experimenting with different machines, matching thread weight to design density is key—an insight equally vital when using mighty hoops or magnetic embroidery hoops to hold fabric without distorting stitches.


Careful Reassembly and Threading

After burr removal and thread evaluation, reassemble the machine carefully. Install the cleaned hook and drop the plastic bobbin in at the six o’clock position, letting it unwind counter-clockwise.

Filing burrs on presser foot
Diamond file used to smooth presser foot burrs.

Correct Bobbin Installation: Counter-Clockwise and Seated

Hold a finger on the bobbin as you pull the thread across the tension slot, ensuring it seats firmly.

Inserting plastic bobbin turning counter-clockwise
Correct bobbin installation ensures counter-clockwise rotation.

Replace the needle plate and tighten screws before threading the upper path.

Proper Upper Threading and Tension Check

Thread with the presser foot up. This opens the tension discs for proper placement. After threading, lower the foot and pull lightly—you should feel consistent resistance. Testing by hand before the first powered stitch prevents tangles.

In conversations online, Randy often reminds users that most malfunctions trace back to simple oversights in these three checks: thread, threading, needle. It’s a comforting truth even seasoned sewists sometimes forget.

If you’re branching into multi-needle or hybrid craft setups, you’ll find parallels between sewing tension checks and hoop calibration—whether positioning fabric in a magnetic hoop or securing garments with hoop master stations.


Final Checks for Jam-Free Sewing

With the machine closed up and tension confirmed, it’s time for one last ritual.

Machine sewing smoothly after repair
Final stitches show smooth performance after adjustments.

Locking the First Stitch by Hand

Always form the first stitch manually to prevent initial slack from knotting underneath. Hold both threads to the machine’s rear, lower the needle, and make one slow turn of the handwheel.

Testing Your Machine with Confidence

Now press the pedal and let the machine hum. The stitches should flow evenly, silky and balanced. Randy finishes with a grin: “All-Purpose Dual Duty works like a charm.”

From the comments: Several sewists shared triumphs—one after twenty-one years of frustration finally discovered metal bobbins were the hidden enemy. Another found that polishing a single burr turned her Kenmore from temperamental to trustworthy.

Machines and makers evolve, yet these mechanical truths stay constant: right materials, smooth surfaces, and steady tension. Apply them faithfully, and the hum of your repaired Kenmore 385 will remind you why we sew in the first place.

If you’re upgrading tools, maintaining precise tension across projects is vital—something equally ensured by advanced framing options like magnetic embroidery frame or the adaptable hoop master embroidery hooping station for embroidery setups.