When you think of heavy duty sewing machines, one of the first machines to consider is the Juki Industrial sewing machine. However, this might not be for everyone. It is expensive and does not come with a lot of features.
But then again, someone looking to sew heavy duty fabrics like leather wouldn't necessarily be looking for a feature-packed machine. However, if you are looking to sew through upholstery fabric and cargo handling belts, you may seriously want to consider the Juki.
You may want to go for the Juki L8-1508 for heavy duty use. It has a triple feed and is not very expensive. It comes with a motor that you can easily adjust the speed on. This particular model of heavy duty sewing machine is made in Japan, so it should stand the test of time.
I have used the Juki for sewing a lot of projects and I like it a lot.
It is important to get the right sewing machine for heavy duty sewing otherwise you might find yourself having to replace needles and being frustrated with broken threads. Most home machines can't handle more than a #69 nylon thread, which is probably the least quality you should go for heavy duty sewing.
Most heavy duty sewing involves straight stitches so you don't need a machine with lots of features. A basic industrial sewing machine is all that is required.
Most vintage machines can also handle heavy duty sewing because that is precicely what they were designed for. Look for machines from the 1920s to 1940s. They are heavy with no plastic parts. They can handle very tough fabrics without breaking down.
In my experience, the Singer heavy duty machines would be one of the best modern options. You need industrial sewing machines because home sewing machines that have the name "heavy duty" in them are not quite the same.
The best heavy duty sewing machines can sew through layers of leather without hesitation. You won't achieve this when you buy a home machine. They'll struggle to feed the heavy fabric through the machine, creating uneven stitches. You may have seen some home machines with the words "heavy duty" in their name but these will fail you.
The best ones to get are the industrial machines. These are designed to sew through some of the toughest fabrics. The downside is that they are expensive, but you can find used low-end models that can do the job just fine.
They may cost you about $600 to $800 from the right dealership. One trick is to carry your heavy-duty fabric to the store and test it with the machine to make sure it can handle it.