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If you’re looking for how to thread a Singer heavy-duty sewing machine, I’ll teach you how using my Singer 4423 heavy-duty sewing machine as an example. Most Singer heavy-duty sewing machines will be threaded in an identical (or very similar) way, so you should be able to thread your own machine at the end of this tutorial. Even if yours is a different model.
This threading tutorial includes step-by-step instructions with lots of pictures and even a video! Diagrams from user manuals are sometimes very confusing, and I always like to see real-life pictures. If you are looking for diagrams, though, you can find them on the quick-start guide included with your machine or the online machine manual.
Specifically, I’ll cover how to wind the bobbin on a heavy-duty sewing machine, how to insert the bobbin, how to thread the upper thread, how to use the optional automatic needle threader, and how to raise the bobbin thread.
So, let’s get going!
(As an aside, I have another tutorial for how to thread a Singer sewing machine if you’re looking for that instead. The process is just slightly different.)
Threading the Singer 4423 Video
My husband recorded a video of me threading my Singer 4423 that you can watch if you prefer video over pictures. Sorry that he’s a bit of an overactive filmer!
How to Wind the Bobbin on a Singer Heavy Duty Sewing Machine
Now, on to the first step. Winding the bobbin on a Singer heavy duty sewing machine happens on the top of the machine and is identical to winding the bobbin on a regular Singer sewing machine. There are some instructions printed on the top of the machine as reminders if you need a refresher.
First, you need to put your thread spool on the spool pin. A horizontal spool pin will also need an appropriately-sized spool holder on the top to keep the thread from coming off once you start sewing.
Then, pull the thread through the first thread guide. You’ll feel it kind of fall into place when you get it through. Don’t pull the thread under the handle when you’re getting to this thread guide.
Next, wind the thread around the bobbin winder tension discs. You need to make sure the thread goes in between the discs; you’ll feel it when it goes between. The thread needs to be wound clockwise as you see in the diagram below.
Pull the end of the thread through the small hole in the top of your Class 15 bobbin. Place the bobbin on the bobbin spindle and push it to the right. Here’s that little hole right before I pushed the bobbin to the right.
While still holding the end of the thread, push slowly on the foot controller to wind the thread just a few times around. I like to take this time to stop and trim the free end of the thread that I was holding.
Now, hands-free, go ahead and push down the foot pedal full speed to wind the bobbin until it is full.
Cut the thread and then push the bobbin spindle to the left again. Remove it from the spindle.
How To Insert the Bobbin on a Singer Heavy Duty Machine
Inserting the bobbin is most safely done with the sewing machine off if you’re not sure what you’re doing.
To insert the bobbin, first, remove the bobbin case cover. There’s a small little tab on the right side that you’ll push to the right to have the cover pop open.
Insert the bobbin where the thread is wound counterclockwise.
Right at 6 o’clock, there’s a small slit in the metal bobbin case. Pull the thread through this slit.
Pull the thread counterclockwise to the left in this slit until you read the small notch. Then, pull the thread out of the notch. If your bobbin is moving during this, hold it in place with a finger. (In the picture below, the notch is just to the right of where the thread is going.)
Pull around 6 inches of thread out from the bobbin and pull it to the back of the plate. Reattach the bobbin cover.
Threading the Upper Thread
First, turn the handwheel towards you on the right of the machine until the needle is at its highest point right before it goes down again. Raise the presser foot. Raising the presser foot is VERY important in avoiding thread tension problems.
Again, it’s safest if the machine is off for this part.
The thread should still be on the spool pin, and the thread spool holder should be holding the thread in place. Take the end of the thread and again pass it through the first thread guide like you did when threading the bobbin.
Pull the thread then through the pre-tension spring at the back of the machine. You’ll pull the thread from back to front to catch it.
Draw the thread down the front of the machine on the right channel.
Make a U at the bottom and pass the thread up the left channel.
At the top of the left channel, there’s a thread takeup lever. Pull the thread from right to left through this lever. If your needle isn’t in the up position, you’ll have issues finding the thread takeup lever.
Pull the thread down again in the same left channel after it’s hooked on the lever.
Below the U on the face of the heavy-duty machine, there’s a horizontal thread guide. The thread needs to go through this. Pull the thread in through the opening on the side.
At the top of the needle, there’s a thin needle clamp guide. Pull the thread through this. There’s also a small opening on the side to get the thread through.
If you don’t have an automatic needle threader, make sure to thread the eye of the needle from front to back. If you do have a threader, keep reading below.
Using the Singer Heavy Duty Automatic Needle Threader
If your sewing machine comes with an automatic needle threader, then threading the eye of the needle will take less effort on your part. I’m not in love with automatic needle threaders as a general rule, but I do think the Singer needle threader is better than the Brother automatic needle threader.
For the needle threader to work, the eye of the needle has to be perfectly placed just-so. If the eye is too high or too low, the hook of the threader will not pass through the hole. You may end up just damaging the threader.
Also, you need to have the stitch dial set to straight stitch, center needle. If your needle is off-center, the threader will also not work.
Now, to work the needle threader, pull the lever on the left of the machine down to its lowest point and rotate it towards you to where the small hook of the threader goes inside the eye of the needle. Wind the thread around the thread guide, which looks like an upside-down metal V. Go over and then under in a counterclockwise manner. I’ve pulled the hook out a little to show you what the hook looks like better.
Pull the thread against the hook that’s in the needle trying to catch it on the very small interior hook. It helps to run the thread from the bottom to the top to catch the hook. Here’s a very zoomed close up of the hook inside the hook.
Once that’s set up, release the lever by rotating it away from you and allowing it to return up to its regular position. You’ll probably have a small loop of thread in the back, so go ahead and pull the end of the thread to the back of the needle. Leave several inches.
Raising the Bobbin Thread to Start Sewing
Even though you’ve finished threading your Singer heavy-duty sewing machine, you’re not ready to start sewing until you raise the bobbin thread.
To do this, hold the end of the upper thread in one hand and turn the handwheel towards you with the other hand. This will advance the needle down and then back up. When the needle rises back up, the bobbin thread will come with it.
Gently tug on the upper thread to bring the bobbin thread up through the hole.
Last, pull both threads back underneath the presser feet.
If your thread won’t raise, make sure it’s not trapped by anything like the bobbin case itself, the extension table, or bobbin case cover.
Conclusion – Singer Heavy Duty Machine Threaded!
Good job! You’ve learned how to thread your Singer heavy-duty sewing machine. Thanks to the easy top-load bobbin and helpful instructions on the body of the machine, threading is a breeze once you’ve done it a few times and committed the process to muscle memory.
Now you can start sewing all your exciting projects!