As a Brother Ambassador working with Brother machines, most of the time I stick with Brother branded thread for the bobbin. This thread is found both on spools to wind yourself or put up on re-usable pre-wound bobbins. These pre-wound bobbins are the same bobbins that come with Brother machines so they are very well made. Side note: Cheap generic bobbins are something I stay away from. Good quality bobbins make a big difference in how your machine operates in both sewing and embroidery mode! While I do actually enjoy winding my own bobbins, another advantage of pre-wound is the fact that they are wound to hold the maximum amount of thread that can be squeezed onto a bobbin. This bobbin thread is available in both black and white. You should be able to purchase both at your local Brother dealer in quantities you prefer.
Other machine brands should check with the manufacturer's reccomendations
Now let's talk embroidery thread. Unless stated other wise, standard embroidery designs are made for 40-50 wt. embroidery thread. Highly magnified, the 40 and 50 weight embroidery thread wold look virtually identical. Good quality polyester fiber is the preferred choice because it is strong and colorfast.
Rayon is an option for embroidery, but you must take great care when washing rayon as it can bleed when wet. It can also fade and does not have the shelf life that poly has. In addition, it breaks and shreds more easily. The prime reason someone would choose rayon would be for color selection. Rayon can be dyed in greater shades because it is more porous. It is also just a tad softer when finished. I rarely use rayon and when I do I take all these precautions into account.
Brand wise, I would stick with the following major brands, Brother, Madeira, and Exquisite. These are the ones I use regularly in my own sewing space.
Below is a link to Brother Brand thread:
Outside the Brother family, I also like Madeira Polyneon 40wt. thread. You can usually find this on both large and small spools so it's an option when you need more or less thread.
Last but not least, I am a huge fan of the Exquisite line of thread sold by DiME. Their Kingstar metallic is excellent as well. By the way, they also sell pre-wound class 15 (one time use/disposable) bobbins in a 60 wt. and a 70wt. I like the 70 wt. best but I do switch out my bobbin case to the one with the purple dot when I use that thread, as it is a bit finer.
Several sewing /embroidery models include this bobbin case with the machine. I like to call it the "just in case" bobbin case. the bobbin case found as the default with the machine has a green screw that is painted and this screw is meant to be left alone. However, the case with the dot inside has an adjustable screw so you can modify the tension as needed. Note that different machines behave differently. Make a sample when using third party bobbin thread and see if you need to make any adjustments. Sometimes I find it necessary to the alternative case for finer bobbin threads.
Below is an *affiliate link to DiME products and the high quality polyester Exquisite brand thread by DiME.
CLICK HERE for DiME embroidery products!
Leave a note in the comments if you have more thread questions or want to share your thoughts.
*Affiliate link: I only recommend supplies I use and love. If you purchase through this link I receive a tiny commission.