Sewing Machine Feed Dogs, my experience.
My first machine was a 1963 off brand Germany machine, only had two stitches, straight and zigzag, had it for almost 40 years, before it got worn out and needed replacement It had only two feed dogs. severed me well, was very strong and did knits ok, but with a lot of fo work.
When it died I decided to get Singer heavy duty machine, a CG590 (was about $250.00), overall ok machine, strong but not as strong as my old machine and was terrible with knits. Tired every presser foot possible (roller, knit, walking, Teflon and so on), and used every method I knew help with knits, Wax paper, tissue paper, spray stretch, tear away stabilizer ect. Knits with this machine was simply a no go.
After a few years of using this machine, a gear slipped, so I went to Walmart picked up an inexpensive Project Runway Brother CE1000 sewing machine (was about $100.00). To my surprise, it is a great machine, as seen through my eyes. And limited exposure to sewing machines. Sews knits like a dream.
Did some research on sewing machines, and leaned it mostly do to the feed dogs, the Singer CG500 only has two, while the Brother CE1000 has 7 feed dogs.
With 7 and amount of different points of contact with fabric, it is much easier to sew with. Especially when doing edge stitching, there is at least 3 or 4 of the feed dogs to feed the fabric through the machine.
As for knits, the Brother CE1000 is great for all of the different knits I have used with it, from sport to tee shirt fabric. Don’t even need to use the specialty feet with knits. A plus has several stretch stitches to choose from.
Unfortunately, when shopping for home sewing machines, they usually do not list how many feed dogs.
On the high-end Juki’s they do have an option for the feed dogs to go in different circle motions to feed from the front of the feed dogs or the back or evenly on them. Would like to try one out one day.