How to Clean and Oil the Bernina 790 Bobbin & Hook Area

Supplies Needed for Bernina Maintenance

Routine hook-area maintenance is the single highest-ROI habit you can build for your Bernina 790. It is the difference between a machine that purrs and one that throws thread nests in the middle of a complex embroidery design. It reduces lint-related tension issues, ensures the thread cutter fires reliably, and keeps the B9 hook running smoothly.

In this guide, we break down the exact sequence used by professionals—what to remove, what to brush, where to oil (precision over volume), and how to verify the magnetic hook is seated correctly.

The Toolkit

The video demonstrates the essentials, but as your educational guide, I am adding the "hidden" consumables that prevent accidents.

Core Tools (Shown):

• Oil Pen/Spout: Precision is key; you need to dispense single drops, not a stream.
• Lint Brush: For mechanical sweeping of dry debris.
• Sewing Machine Oil: High-quality, clear mineral oil specifically for sewing machines.

Hidden Consumables (The "Safety Net" for New Users):

• Micro-tip Snips: For surgically removing thread tails trapped near the cutter (fingers are too clumsy).
• Paper Towel/Shop Cloth: To catch accidental over-spray.
• Task Lighting: You cannot clean what you cannot see. Use a bright LED directed into the hook race.
• Magnetic Tray: To hold the stitch plate and screws so they don't vanish under your table.

Warning: Needle & Cutter Risk. The area under the stitch plate contains sharp blades (thread cutter) and potential needle burrs. Do not blindly jam the brush into crevices. Brush gently, keep fingers clear of the cutter mechanism, and use snips—not force—to remove stubborn threads.

Prep Checklist (Pre-Flight)

Before you unscrew a single part, ensure your environment is ready to prevent lost parts or damage.

• Surface: Table is flat, clear, and well-lit.
• Tools: Oil pen and lint brush are within arm's reach.
• Safety: Machine needle is raised to the highest position; embroidery module is removed (if attached).
• Control: A designated tray or spot is cleared for the stitch plate and foot.
• Hygiene: Hands are clean to avoid transferring grease to the machine exterior.

Disassembling the Work Area

We follow a strict order of operations: clear access first, then expose the mechanism. This prevents you from struggling with angles or dropping screws into the machine.

Removing the Presser Foot

Goal: Create visual and physical clearance for the stitch plate removal.

Action:

1. Raise the needle to its highest point.
2. Slide the clamp lever up.
3. Remove the foot completely.

Sensory Check: You should have a completely unobstructed view of the stitch plate.

Unlocking the Stitch Plate

Goal: Expose the feed dogs and hook race.

Action:

1. Locate the "Bullseye" target marking on the stitch plate (back right corner).
2. Press firmly on the bullseye. The front of the plate will pop up.
3. Lift the plate straight up toward the ceiling.

Expert Insight: Do not pry the plate with a screwdriver. The mechanism is designed to release with downward pressure on the target spot. If it resists, check for lint jamming the release mechanism.

Cleaning the Bobbin and Hook System

This is the core of the maintenance routine. You are removing "packed" lint—fibrous dust that has been compressed into felt-like pads that obstruct mechanical movement.

Clean the Stitch Plate & Needle Entry

Action:

• Inspect the underside of the stitch plate.
• Use the brush to sweep the "feed dog slots" and the needle entry hole.

Success Metric: The metal should be shiny, with no grey fuzz clinging to the corners.

Remove and Clean the Bobbin Case

Action:

1. Open the bobbin door.
2. Squeeze the latch lever to release the bobbin case.
3. Remove the bobbin from the case.
4. Brush the interior: Sweep the entire inner circumference of the black bobbin case.

Sensory Check: Run your fingertip gently inside the case. It should feel perfectly smooth. Any grit here causes irregular tension.

Open the Hook Race & Remove the Hook

Action:

1. Locate the release lever on the left side of the hook race.
2. Press the lever; the translucent race cover will drop down (hinged at the bottom).
3. Grasp the center of the hook and pull gently. It is held by magnetism, not screws.

Sensory Check: You will feel a slight magnetic resistance, then it will release.

Deep Clean: Hook, Race, Dogs, and Cutters

Action:

• The Hook: Wipe the back and front. Polish it with a clean cloth.
• The Race (Cavity): Brush out all lint. Look for "grey corners"—lint loves to pack into the back.
• The Cutters: This is critical. Use your snips to grab any thread tails trapped in the cutter blades on the right side.

Expert Insight: Lint isn't just cosmetic. In the cutter area, it acts like a sponge for old oil, creating a sticky paste that jams the knife. If your auto-cutter has been failing, 90% of the time, the culprit is packed lint here.

Where to Oil the Bernina 790

Bernina machines require specific lubrication. More is not better. Excess oil attracts lint faster, creating "grinding paste."

Point 1: The Red Felt Reservoir

Action:

• Locate the small red felt circle on the hook race.
• Apply exactly one drop of oil.
• Frequency: Every 8 hours of sewing or embroidery, or every 3-4 bobbin changes during heavy use.

Visual Check: The felt should look damp/darker red, but not glistening wet.

Point 2: The 6 O'Clock Position

Action:

• Look inside the hook race cavity.
• Apply one tiny drop (pinhead size) to the metal track at the 6 o'clock position (bottom center).

Warning: Over-Oiling Risk. Do not flood the race. If you see oil pooling or running down the side, you have used too much. Wipe it away immediately with a paper towel. Excess oil will be thrown onto your next project by the centrifugal force of the hook.

Reassembly and Alignment

This is where beginners often panic. Learn the sensory cues of a correctly seated system.

Aligning the Magnetic Hook

Action:

1. Hold the hook by the center pin.
2. Visual Anchor: The triangular "point" of the hook driver must point straight up (12 o'clock).
3. Align the two slots on the back of the hook with the metal tabs in the machine.

The "Magnetic Snap"

Action:

• Let the magnet do the work. Guide it in.
• When aligned, it will jump out of your fingers.

Sensory Check: Listen for a solid "Click". Touch the hook—it should feel firmly locked, not wobbly. Final Step: Lift the translucent race cover until it clicks shut.

Reinstalling the Bobbin Case

Action (Detailed):

1. Bobbin Orientation: Hold the Jumbo Bobbin so the silver (metal) side faces the bobbin case. (Silver side in).
2. Drop the bobbin in.
3. Thread Path: Pull the thread through the slit, under the tension spring, and through the pigtail guide.
4. Insert Case: Hold the latch horizontal. Insert into the machine.

Sensory Check: You must feel a tactile snap when the case locks in. If it feels springy or doesn't click, remove and try again.

Final Closure

Action:

1. Cut the thread tail on the built-in cutter.
2. Close the bobbin door.
3. Stitch Plate: Insert the front tabs first, then push the back corners down until they lock ("Snap").
4. Reattach the presser foot.

Setup Checklist (Reassembly Verification)

• Hook: Pointed up (12 o'clock) and magnetically seized.
• Cover: Hook race door is clicked shut.
• Bobbin: Silver side faces IN; thread routed through tension spring.
• Case: Clicked firmly into the race.
• Plate: Lying fundamentally flat; no rocking.

Primer (Hook + What you’ll learn)

If your machine sounds "clunky" or your thread cutter is shredding rather than cutting, the issue is rarely digital—it is physical. This maintenance routine cleans the "arteries" of your machine.

However, maintenance is only half the battle. If you maintain your machine perfectly but still struggle with hooping fabric, you are solving the wrong problem. As you master this cleaning routine, keep in mind that your workflow tools (like a magnetic embroidery hoop) are the next step in your evolution from novice to pro.

Prep (with decision points and upgrade paths)

Before you start your next project, run this decision logic to ensure you aren't fighting your equipment.

Decision Tree: Maintenance vs. Tooling

Scenario A: "My machine is loud / Cutter isn't working"

• Diagnosis: Mechanical obstruction.
• Solution: Perform the cleaning routine detailed above (20 minutes).

Scenario B: "My machine runs fine, but hooping takes forever / I get hoop burn"

• Diagnosis: Workflow bottleneck.
• Solution: Upgrade your hooping technology.

Tool Upgrade Path

If you are doing production runs or working with delicate fabrics, traditional screw-hoops are a liability. They cause hand fatigue and fabric markings ("hoop burn").

• The Problem: Traditional hoops require physical strength and leave residue marks.
• The Fix: bernina magnetic hoops utilize magnets to clamp fabric instantly without distortion.
• Compatibility: Ensure you select magnetic hoops for bernina embroidery machines specifically designed for the B-hook clearance.

Warning: Magnet Safety. Powerful magnetic hoops can pinch fingers severely. They can also damage pacemakers and erase credit cards. Store them flat and away from sensitive electronics. Never let children play with them.

Operation (step-by-step with checkpoints)

For your daily workflow, use this abbreviated Standard Operating Procedure (SOP).

The 10-Minute Routine

1. Clear: Remove Foot & Plate.
2. Sweep: Brush Plate underside & Feed Dogs.
3. Extract: Remove Bobbin Case & Hook.
4. Deep Clean: Brush Hook Race & Cutters (Check for threads!).
5. Lube: 1 drop on Red Felt; 1 drop at 6 o'clock.
6. Reset: Insert Hook (12 o'clock) -> Close Door.
7. Load: Bobbin (Silver In) -> Case -> Machine.
8. Lock: Plate (Front tabs first, snap back) -> Foot.

Operation Checklist (Final Go/No-Go)

• Red Felt: Damp (1 drop), not flooded.
• Race: 1 drop at 6 o'clock.
• Hook: Snapped in securely.
• Cutters: Clear of all thread debris.
• Sound: Hand-wheel turn is smooth, no grinding noise.

Quality Checks (avoid rework and protect stitch quality)

After any maintenance session, "trust but verify."

The Confidence Stitch: Run a simple straight stitch on a scrap piece of fabric for 10 seconds.

• Why? This clears any excess oil that might have dripped into the needle path, preventing oil stains on your expensive garment.
• Listen: The machine should sound rhythmic and soft, not harsh or clattering.

Production Efficiency Note: If you pass the quality check but still find yourself dreading the setup process for each shirt, investigate a magnetic hooping station. A proper hooping station for embroidery machine ensures consistent placement every time, turning a chaotic hobby into a repeatable business process.

Troubleshooting (symptom → likely cause → fix)

Structured problem-solving prevents you from changing random settings when the fix is simple.

Results

You have now performed a factory-level maintenance service on your Bernina 790. By sticking to the "12 o'clock rule" for the hook and the "Silver-Side-In" rule for the bobbin, you eliminate 90% of user errors.

Remember: Maintenance protects the machine; tools protect your sanity. If you are ready to stop fighting with hoops and start stitching faster, consider looking into a compatible bernina magnetic embroidery hoop or a snap hoop for bernina. The right tools, combined with this maintenance discipline, turn friction into flow.