If you want to have a longer "step," you will probably need a larger machine. The limit of that length factors in things like the max thread size and how much tension the machine can maintain. Your machine is for sewing clothes, the longer stitch lengths will be for a more decorative use and would not be durable as a main support stitch.
I understand you know how to change the step length that can be changed now, yes? You say <2mm to 5mm. My very similar machine can go to almost 10mm but it cannot keep the thread very tight. This is the limiting thing, the machine, every part, is designed for sewing a length of 2-8mm or whatever. A longer stitch step would need a complete change and probably a stronger motor.
By moving the knob or lever that changes the stitch step length, you will see what is going on.
I understand you know how to change the step length that can be changed now, yes?
Yea
You say <2mm to 5mm. My very similar machine can go to almost 10mm but it cannot keep the thread very tight.
I would die for 10 mm.
I would be in to adjust the machine while sewing for any step lenght larger then 5 but 10 mm would be perfect.
This is the limiting thing, the machine, every part, is designed for sewing a length of 2-8mm or whatever. A longer stitch step would need a complete change and probably a stronger motor.
I can change gearings, leverages and axles if I understand what to communicate.
I am not bound to the current chassis and motor. I can construct a chassis afterwards rezpecting current alignments within nm.
By moving the knob or lever that changes the stitch step length, you will see what is going on.
I circled the change in blue.
Leveraging the handle could be the case but axles wind on their own.
It is a mind fuc* which can only be put in perspective by Engineers, imo.
I am not an engineer, either 🤔 I see your front picture, my machine is similar. I would not be able to change anything myself. As
gadfly1999
mentioned, these really are highly engineered. If you change one thing, you must change everything.
The important thing is tension, for the thread to be tight. If you can do this, happy engineering! My similar machine, tension on the string is hard, more with a longer length/step.