Restore a balance wheel? What in the world does that even mean? Well, I just completed a tutorial on restoring a Singer potted motor. As I got to the end, it dawned on me that the process naturally incuded removing and reinstalling the balance wheel. Well, the balance wheel on these two machines is not the same solid balance wheel found on other Singer machines of the same vintage. The difference is the potted motor… A belt driven sewing machine has a solid balance wheel, while a machine with a potted motor has a “textolite” gear attached to the balance wheel that is driven by a worm gear on the motor.
This is where my attention to restoring the balance wheel on these machines comes from. These balance wheels have a shock absorbing mechanism built into the balance wheel hidden from view by the “textolite” gear. You can see how this works by holding the balance wheel in one hand and turning the gear in the other. The gear will move in relation to the balance wheel by about a quarter of an inch before it engages… in either direction. Singer included this feature to absorb the shock of the gear drive in starting or stopping the sewing mechanism.
I don’t know that many people know this mechanism exists, or that the machine can be improved by addressing it. I do know that I have come across many, and none have had any indication of being previously serviced. after 60 to 80 years of service, it just makes sense that the grease lubricating this mechanism has outlived its purpose, my experience with disassembling and servicing these balance wheels supports this. The same general process will work on other gear driven machines including the 301, 401A/403A, and 500A/503A.
It’s really easy… takes 15 minutes… the balance wheel is easily removed… it makes a noticible difference in how the machine feels… and I want to presuade you check this off of your maintenance list for your machine that once done, should last for years.
This is a short tutorial so I will begin…
There are two configurations of these balance wheels. One has a collar with three screws retaining the gear, the other uses a “horse shoe” spring clip retainer. Here is a picture showing both. The pictures I used in this tutorial are a combination of both. The parts and process from the textolite gear down are the same.
The only difference in disassembly is this… One begins with loosening the screws and removing the collar. The other begins with removing the horse shoe clip. The horse shoe clip is a bit more challenging, but it simply involves prying the clip wider and away from the groove it sits in. There are two holes on the end of the clip for this purpose. There is a tool that is specially made for this, (like in the picture) but I have found that a pair of needle nose pliers works just as well.
Remove the collar or clip.
Remove the “textolite” gear.
Remove the thin metal cover.
What you see underneath is a spring with one end engaged with a stud in the balance wheel. Inside of the spring are two eccentric studs that pivot in their holes… remove the spring and eccentric studs.
Clean all of these parts.
Apply grease (I used Singer grease lubricant, any sewing machine grease will do) to the back of the textolite gear, eccentric studs, spring, and the area in the balance wheel these reside. Reinstall the eccentric studs and spring. Remember one end of the spring goes on the fixed stud in the balance wheel.
Replace the metal cover, the textolite gear, and the horse shoe clip or screw collar.
Apply grease to the gear teeth and the worm gear and reinstall the balance wheel.
You will notice the difference immediately and the mechanism will function as it is did when new!
I hope that this tutorial has helped you and answered a few questions in the process. Don’t hesitate to contact me if you have any questions, and please visit our Etsy store at https://www.etsy.com/shop/pungoliving, to see our restored fine high quality sewing machines.
As always, our tutorials are provided as a free resource to help you learn and maintain your vintage sewing machine. As our site has grown, so has the cost to keep and maintain it. Despite these cost, I will strive to continue posting tutorials and other relevant content for the benefit of the sewing community. If you found the content of this tutorial useful, please consider making a small donation to help me grow the site and help defray my costs… every little bit helps.
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