TAJIMA SAI SETUP GUIDE - PREPARATION -

(Top embed module notice: This article is based on the video “TAJIMA SAI SETUP GUIDE - PREPARATION -” from TAJIMA INC. The steps below are written to stand alone as a complete, repeatable workflow for new users.)

If your machine is "almost" threaded but keeps breaking thread, birdnesting (bunching up underneath), or refusing to form consistent stitches, the cause is rarely a mechanical failure. In 90% of cases, it is one missed guide, one wrong routing direction, or one tension disk that never actually opened.

As a technician with 20 years in the field, I can tell you that successful embroidery is less about magic and more about a strict checklist. This guide turns the standard setup instructions into a fail-safe routine you can use on your Tajima SAI—or even when applying similar principles to SEWTECH multi-needle machines.

What you’ll learn

• The "Home Base" Layout: How to map needle numbers to cone placement so you never pull the wrong color.
• The Critical Pressing Shaft: The hidden step 50% of beginners miss that kills tension control.
• The "Drop Test": How to physically feel if your bobbin tension is correct.
• Workflow Efficiency: How choosing the right compatible accessories, like magnetic frames, can stop fabric slippage.

1. Initial Thread Stand Setup

Understanding the Needle Order (1–8)

The video specifies that the upper thread order from No.1 to No.8 is set counterclockwise from the front right.

• Front Right = Needle #1
• Front Left = Needle #4 / #5 (depending on the stand circle)
• Back Right = Needle #8

This single sentence is critical. If you load this randomly, your digitizer’s color chart won’t match your machine output. Treat this as your "Home Base." Even for a simple 3-color logo, keeping the stand organized prevents "crossover" tangles where thread from the back drags across a cone in the front.

Placing Cones Correctly

Place your cones on the spool pins, confirming the counterclockwise numbering.

• Slack Check: Ensure the thread coming off the cone goes straight up to the guide tree without wrapping around the spool pin itself.
  
  Quick check

  Before threading, pull about 12 inches of thread from each cone. It should flow flawlessly. If it jerks, check for tangled "spider webs" of thread at the base of the cone.

Hooping Insight: A perfect thread path can't fix a loose garment. In many professional shops, operators rely on a dedicated set of tajima embroidery hoops sized specifically for the logo (e.g., using a 15cm hoop for a 12cm design) to ensure the fabric remains drum-tight and registered correctly throughout the job.

Prep checklist (Thread stand)

• Cones arranged No.1–No.8 counterclockwise from the front-right.
• Plastic burrs removed from cone bases.
• Thread ends are separated and feeding straight up.

2. Upper Threading Procedure

Using the Guide Tube and Pressing Shaft

Begin by hooking the upper thread onto the tip of the upper thread guide, then inserting it into the thread tube from the opposite side. This protects the thread from environmental dust and static before it hits the machine.

CRITICAL STEP: You must lift up the thread pressing shaft before routing through the tension disks.

Why this is non-negotiable: The tension disks are like two metal plates pressed together. Lifting the shaft separates them. If you thread while the shaft is down (closed), the thread will "float" on top of the disks rather than seating between them. The result? Zero tension, immediate thread shredding, or massive loops on the back of your embroidery.

Safety Warning: Always keep fingers, loose jewelry, and tools away from the needle bar area and take-up levers when the machine is powered on.

Routing Through Tension Disks

With the shaft lifted, pass the thread through the pretensioner (the first small guide), around the main tension wheel, and through the thread breakage sensor. Then, route it along the groove of the top cover and through the take-up lever eyelet.

The Arrow Rule: Look closely at the thread breakage detection disk (the wheel that spins). There is an imprinted arrow. You must wrap the thread in the direction of that arrow.

• The Consequence: Going against the arrow can cause the sensor to misread normal stitching as a thread break, causing the machine to stop falsely every few seconds.
  
  Quick check

  After routing, gently pull the thread near the needle. You should feel a smooth, "waxed floss" sensation—consistent resistance, not a gritty scraping feeling.

Needle Bar and Threader Tool Tips

Route the thread down the faceplate groove, through the lock shaft, needle clamp, and finally the needle eye.

Using the Threader Tool (Save your eyes):

1. Keep the triangle mark on the tool facing up.
2. Insert the thread sideways into the tool's slot.
3. Slide the threader down the needle groove until it "catches" the eye.
4. Push gently; a loop of thread will poke through.
5. Pull the loop out from the back.

Common Question: "Do I thread all 8 needles?" Answer: You only must thread the needles used in your design. However, professionals keep all needles threaded with standard colors (Black, White, Red, Blue) to minimize downtime between jobs.

Setup checklist (Upper threading)

• Thread pressing shaft was LIFTED during threading.
• Thread wraps the detection disk in the direction of the specific arrow.
• Thread is passed through the take-up lever eyelet (missing this guarantees a break).
• Thread pressing shaft is pushed DOWN (clicked) after threading is done.

3. Mastering the Bobbin Case

Correct Winding Direction (Clockwise)

Open the hook cover and remove the bobbin case. When inserting a new bobbin, the video specifies the winding direction should be clockwise.

The "check" is vital: Hold the bobbin case in your hand and pull the thread tail. Use the video's verification method: guide the thread through the slit and under the tension spring leaf. When you pull the thread now, the bobbin inside should rotate counter-clockwise. If it rotates the other way, take it out and flip it.

The "Drop Test" (Setting Tension)

Tension is a balance between the top (tight) and bottom (loose). To test the bottom: suspend the bobbin case by the thread tail over your hand (in case it falls).

1. Motionless: The case should not slide down by its own weight.
2. The Bounce: Give your wrist a gentle sharp jolt (like playing with a yo-yo).
3. Result: The case should drop 1–2 inches and then stop.

Analysis:

• drops to the floor immediately: Too loose.
• Doesn't move at all: Too tight.

Adjusting the Tension Screw

If the test fails, use the tiny flat-head screwdriver to turn the larger screw on the side of the case.

The "Minutes" Rule: Think of the screw as a clock face. Only turn it 5 to 10 "minutes" at a time. A quarter-turn is huge in embroidery terms. Adjust, re-test, repeat.

Workflow Upgrade: If you have dialed in your tension but still struggle with hooping thick items (like hoodies) quickly, consider using magnetic hoops for tajima embroidery machines. These allow you to float backing and clamp thick seams without forcing the inner ring, which preserves the tension balance you just set.

Warning: Magnetic hoops are powerful. Slide them apart to open them—do not try to pull them straight apart. Keep fingers clear of the snapping zone to avoid painful blood blisters.

4. Final Machine Prep

Inserting the Bobbin Case

Pull out about 5 cm (2 inches) of thread tail. Hold the latch open (or hold the case by the body) and push it onto the rotary hook post.

The Audible Click: You must push until you hear or feel a distinct click.

• No Click = Disaster. If the case is not clicked in, it will fly out or spin correctly as soon as the machine hits 800 RPM, causing the needle to strike the case and explode the bobbin thread (Birdnesting).

Close the front cover.

Hidden Consumables & Prep Checks

Your setup is only as good as your consumables.

• Needle Choice: For standard woven cotton, use a 75/11 Sharp. For knits (polos/t-shirts), use a 75/11 Ballpoint to avoid cutting fabric fibers.
• Stabilizer (Backing): Never embroider without it. Use Cut-away for anything that stretches (clothing) and Tear-away only for stable items (towels, bags). Upgrading to high-quality SEWTECH stabilizers can significantly reduce puckering.
• Topping: If sewing on fleece, velvet, or towels, lay a piece of water-soluble topping over the fabric so stitches don’t sink into the pile.

Operation / Steps checklist (Ready-to-sew verification)

• Needle #1 is Front Right (Counter-clockwise order).
• Thread pressing shaft is clicked DOWN/LOCKED.
• Upper thread path follows the sensor arrow.
• Bobbin passed the "Drop Test" (drops slightly with a bounce).
• Bobbin case is inserted with a positive CLICK.

5. Results & Troubleshooting Guide

You have now completed the professional "Preparation" stage. By standardizing your cone order and verifying tension with the drop test, you have eliminated variables that confuse operators.

When handing off the machine to a colleague, stick a piece of masking tape on the machine head listing the current thread colors loaded. This simple habit prevents ruining a garment because someone assumed Needle 3 was Blue when it was actually Black.

Finally, match your frame to your job. While a standard generic hoop works for flat cloth, specific jobs like pockets or structured caps require specialized tooling like a tajima pocket frame or a tajima cap frame to get close enough to the seam without flagging.

Rapid Troubleshooting: What to check first?

If the machine stops or fails, don't guess. Follow this order:

1) The "Birdnest" (Thread bunching up under the fabric)

• The Myth: "It's a bobbin problem."
• The Reality: It is usually an Upper Thread problem. If the top thread has no tension (because it jumped out of the take-up lever or the pressing shaft wasn't lifted during threading), it feeds too much slack, creating a nest below.

2) Thread Breaks Immediately (First 5 stitches)

• Likely Cause: Incorrect needle installation or burred needle.
• Check: Is the needle inserted all the way up? Is the "scarf" (the indentation) facing the back?

3) Bobbin Thread Showing on Top

• Likely Cause: Top tension too tight OR Bobbin tension too loose.

4) Design Outline is Off (Registration Error)

• Likely Cause: Fabric slipping in the hoop.

5) False Thread Break Alarms (Machine stops, but thread is fine)

• Likely Cause: Thread routed against the arrow on the sensor wheel.