The BEST tutorial on How to Thread an Overlocker, the Bernina L450 or L460 Serger

Learn how to thread your Bernina L450 or Bernina L460 serger/overlocker with this step-by-step photo and video tutorial. 

Do you hate to thread your serger?  Or worry every time you have to thread your serger?  If you answered yes to either of these questions, follow this tutorial and get familiar with threading your overlocker.  It's really not as hard as you think!

Threading an overlocker can be a daunting task, especially if you are new to using this type of machine. In this article, we will provide step-by-step video and photo instructions on how to thread a Bernina L450 or L460 overlocker/serger, making the process as simple and straightforward as possible.

Our video and photo tutorial shows every step for each thread separately!  To see a video of threading each thread, click the link below to watch the full video on YouTube.  The video on the page below is just a preview.

Many sergers have a similar threading path, so even if you have another brand or model of serger, this tutorial may help you get yours threaded. 

Learn how to thread an overlocker or serger by clicking the link to watch our video or keep reading this post.

Threading Improvement Over My Old Bernette Serger

I have an old Bernette serger from the 1980s. The older serger is threaded almost the same as this new one with one important exception. 

When changing the thread on my old serger, I would have to thread and rethread it multiple times until I could get it right.

This is because the red thread passes around the back of the lower looper, loop onto the hook and through the eye on the looper.  If it wasn't threaded perfectly, it would come unthreaded or the thread would break.  It was difficult to get this correct.

This new serger has one feature that makes it so much easier to thread. The lever shown in the photo below makes a huge difference in the ease of threading this serger by eliminating the need to wrap the thread around the back of the lower looper.

The lever does that part of the threading for you! Later in this tutorial, I will be stepping through the threading process. Pressing the lever brings forward a hook and the thread is looped over the hook. Once the machine starts stitching, the hook moves to the back of the lower looper and completes the threading for you.

Color Coding of Thread Paths

Bernina sergers/overlockers all have color-coded thread path markers to aid in the threading of the overlocker.

In this tutorial, to help you see the different threads, I will thread each with colors matching the color coding on the machine. Normally, when stitching with your overlocker, use matching thread color in all four spools.

The color coding on the machine is:

• Yellow – left needle
• Green – right needle
• Blue – overlock upper looper
• Red – overlock lower looper

Two Methods for Threading an overlocker: Bernina L450 or Bernina L460 Serger

I will be demonstrating two ways to thread the overlocker.  One is a quick way but it doesn’t always completely work.  The 2^nd is how to fully thread your overlocker.

Prepare to Thread the Serger / Overlocker

Prepare to thread the serger/overlocker machine by:

• Turning off the machine
• Raise the presser foot to release the tension
• Raise needles to the top position

To raise the needles to their highest position, turn the handwheel towards you until the red line is centered in the window. See the photo below for the location of the needle position window and what the mark looks like.

If you have an L460, the machine automatically stops with the needle up.

Method 1: Thread the overlocker by pulling new threads through the thread path

The simpler method for changing the threads on the serger/overlocker is to tie the new color onto the old one and then pull the threads through the machine.

When I need to change the thread on my serger, I usually try this method first.  Sometimes the threads will break so then I’ll have to finish threading manually.  But, if it works, it’s a quick way to change threads.

Steps for threading method #1:

1. Start with the machine off, the presser foot raised and the needles in the top position.

2. Cut off each thread near the spool.  Leave the threads hanging on the retractable thread guide.

3. Replace thread four spools with the new thread color. For this demonstration, I replaced them with colors that match the guide colors.  Normally you would use the same color thread for all four spools.

4. Tie the end of the new thread to the cut-off thread for each spool.

5. Gently pull the thread tail until you see the individual threads and then cut the tail off.

6. Open the lower looper cover.

7. Gently pull each thread individually through the machine.

8. For the yellow and green threads, the knot probably will not pass through the needles. If it doesn't, cut it off and then thread the needle.

If one of the threads breaks while pulling it through, it will need to be threaded manually following the directions in Method #2.

Once all threads are pulled through, close the looper cover, lower the presser foot and turn on the machine.

Test sewing on a scrap piece of fabric to ensure it’s threaded properly and the stitches are forming correctly.

And the color is changed!

If the test stitching does not form the stitches correctly, take a look through each thread path to make sure it's threaded correctly.  If the reason cannot be determined, I recommend threading the machine as described in Method #2.

Method 2: step-by-step threading an overlocker

This next section will step you through threading the serger.  Start by removing any thread from the serger. 

Threading Guide

The Bernina L450 & L460 sergers have a threading guide printed inside the looper cover.  This guide is very helpful to follow when you are threading the machine. 

The manual that comes with the Bernina L450 or L460 also has a color-coded threading diagram at the end of the manual.  If you don’t have a manual, scroll to the end of this tutorial for a link to download the manual from the Bernina website.

OUR PRINTABLE TUTORIAL AND QUICK GUIDE

If you like this tutorial and want a printable version, please visit our Etsy shop listing, The BEST tutorial on How to Thread an Overlocker, the Bernina L450 or L460 Serger - PDF Download.  This instant download includes an 18-page printable of this article including all photos and instructions and is ad-free.

The listing also includes our four-page printable Quick Threading Guide which is perfect to keep by your serger.

If you would like just the Quick Guide: Threading a Bernina L450 / L460 Serger - PDF Download, this is also available separately in our Etsy shop.

Both are offered at a small fee.  Thank you for supporting our site and YouTube channel by making purchases! 

We hope you enjoy the rest of this tutorial for Free but supported by ads. 

Serger Threading Order

One very important thing to note is the numbers on each of the threads in the threading diagram.  The machine MUST be threaded in the order indicated in the diagram.

1. Blue – upper looper
2. Red – lower looper
3. Green – right needle
4. Yellow – left needle

This tutorial will follow this order when threading the machine.

Steps for threading the Bernina L450 or L460 Serger / Overlocker

1. Start with the machine off, the presser foot raised and the needles in the top position.

2. Lift the retractable thread guide.

3. Place the thread spools on the spool holders.

Spool stabilizers are included with the machine and should be used with spool cones. If you have a large cone, the spool stabilizer should be placed with the wide side facing up. 

For small cones, the spool stabilizer would face down.  If you are using a standard thread spool use a thread cap on the top of the spool.

For polyester or bulky nylon threads, thread nets are also included with your serger.  Using these over your thread spool will help the thread to feed consistently.

4. Open the lower looper cover.

FIRST THREAD: Upper Looper (blue)

Start threading the serger with the upper looper thread indicated by the blue dots.  In this demonstration, I am threading a blue thread through this thread path.

The blue thread is the third thread from the left.  Always start threading with this thread!

Steps for threading the 1st thread: Upper Looper (BLUE)

1. Retractable Thread Guide: Place the blue thread through the retractable thread guide above the spool. The thread should go from back to front over the guide above the blue thread.

2. Pretension Hook: Hold the thread on both sides and slip it into the pretension hook marked with the blue dot.

3. Tension Wheel: Pull the thread down through the tension wheel in front of the pretension hook indicated by the blue dot.

4. Looper Cover Area: Follow the path through the next three thread guides indicated by the blue dots and shown as numbers 4, 5, and 6 in the photo below.  Hook the thread onto these hooks. 

5. Upper Looper: Hook the thread into the wire guide on the side of the upper looper indicated by the blue mark and the number 7 in the photo above.

6. Upper Looper: Thread through the hole in the upper looper indicated by the number 8 in the photo above. The tweezers included with your machine can be used to make this easier to thread.

7. Finally pull out a few inches of thread and place it under the presser foot.

Steps for threading the 2nd thread: Lower Looper (RED)

The next thread in order is the lower looper thread indicated by the red dots.  In this demonstration, I am threading a red thread through this thread path.

The red thread is on the far right side.  This is always the 2nd thread!

1. Retractable Thread Guide: Place the red thread through the retractable thread guide above the spool. The thread should go from back to front over the guide above the red thread.

2. Pretension Hook: Hold the thread on both sides and slip it into the pretension hook marked with the red dot. 

3. Tension Wheel: Pull the thread down through the tension wheel in front of the pretension hook indicated by the red dot.

4. Looper Cover Area: Follow the path through the next four thread guides indicated by the red dots and shown as numbers 4, 5, 6 and 7 in the photo below.  Hook the thread onto these hooks.

5. Looper Threader Lever: Push down the looper threader lever indicated by the number 8 in the photo above.

6. Looper Threader Lever Hook: Hook the thread on the looper threader hook indicated with the number 9 in the photo above.

7. Lower Looper: Thread through the hole in the lower looper indicated by the number 10 in the photo above. The tweezers included with your machine can be used to make this easier to thread.

8. Upper Looper: Take the thread OVER the upper looper as shown in number 11 in the photo above.  The red thread is going over the looper.

9. Finally, pull out a few inches of thread and place it under the presser foot.

Steps for threading the 3rd thread: Right Needle (GREEN)

The next thread is the right needle indicated by the green dots.  Always thread this before the left needle (yellow).  

1. Retractable Thread Guide: Place the green thread through the retractable thread guide above the spool. The thread should go from back to front over the guide above the green thread.

2. Pretension Hook: Hold the thread on both sides and slip it into the pretension hook indicated by the green dot. 

3. Tension Wheel: Pull the thread down through the tension wheel in front of the pretension hook indicated by the green dot.

4. Thread Guide: Loop the thread around the thread guide indicated by the number 4 in the photo below.  Wrap the thread from the right towards the left.

5. Loop the thread around the thread guide at the bottom of the take-up lever slots, indicated by the number 5 in the photo above.

6. Take-Up Lever Slot: Slide the thread into the lower take up lever slot indicated by the green dot and the number 6 in the photo above.

7. Needle Holder Thread Guides: Place the thread into the RIGHT side of the two thread guides above the needles indicated by the numbers 7 and 8 in the photo below.

8. Thread the Needle: Finally, thread the needle on the RIGHT side (number 9 in the photo above)  and pull out a few inches of thread and place it under the presser foot.

The needle threader included with the machine can help you thread the needle.

Steps for threading the 4th thread: Left Needle (YELLOW)

There is one last needle to thread.  If you are only stitching a three-thread overlock or another stitch with only three threads, the needle may not be threaded. Always remove the needle and lightly tighten the screw if you are not threading it.

1. Retractable Thread Guide: Place the yellow thread through the retractable thread guide above the spool. The thread should go from back to front over the guide above the yellow thread.

2. Pretension Hook: Hold the thread on both sides and slip it into the pretension hook indicated by the yellow dot. 

3. Tension Wheel: Pull the thread down through the tension wheel in front of the pretension hook indicated by the yellow dot.

4. Thread Guide: Loop the thread around the thread guide indicated by the number 4 in the photo below.  Wrap the thread from the right towards the left.

5. Loop the thread around the thread guide at the bottom of the take-up lever slots, indicated by the number 5 in the photo above.

6. Take-Up Lever Slot: Slide the thread into the upper take-up lever slot indicated by the yellow dot and the number 6 in the photo above.

7. Needle Holder Thread Guides: Place the thread into the LEFT side of the two thread guides above the needles indicated by the numbers 7 and 8 in the photo below.

8. Thread the Needle: Finally, thread the needle on the LEFT side (number 9 in the photo above) and pull out a few inches of thread and place it under the presser foot.

Close the Looper Cover

Once all threads are threaded, close the looper cover, lower the presser foot and turn on the machine.

Test sewing on a scrap piece of fabric to ensure it’s threaded properly and the stitches are forming correctly.

The serger is threaded!

If the loops do not form or the thread breaks, check your steps and try again.

If the loops form but are not even, adjustments can be made to the micro thread control lever and tension. 

Before making any adjustments, make sure the tension dials are all set to the default value, 4.  This standard setting is indicated by a dot next to the number 4.  Set the micro thread control lever to the default, middle position. 

Test the stitches again. If they are still not even, refer to the owners manual for suggestions on adjustments to be made depending on the issue.

Review of the Dials and Knobs on the Bernina L450 / L460

In case you missed our Introduction to Bernina L450 / L460 serger tutorial, here is a review of some of the knobs and dials.   

On the right side of the machine are the stitch length dial and differential dial.  The large dial is the handwheel.

On the front of the machine is the cutting width dial.

The micro thread control lever and the rolled hem selection lever are on the side front. The knife is behind the knife guard.

If you need to disengage the knife, the lever is under the sewing table cover.

If you would like to learn how to sew inside and outside corners and secure seams with your serger, click the link for the tutorial.

To read a tutorial by Bernina on how to thread a serger, please click the link.

We hope you enjoyed learning how to thread a Bernina L450 / L460.

Some other serger tutorials and projects:

• How to Sew a Napkin
• Free Stuffed Bunny Pattern & Tutorial
• Re-usable Unpaper Towels Tutorial
• How to sew a Rolled Hem with a Serger