Quiltingboard Forums - What makes a machine sew fast?

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Thanks, Quilterman. I'm not going to remove the motor, though. My mechanical skills don't go much further than clean and oil.
bkay

This is a video about how to measure the speed with a Smartphone. I have tested it, at it gives results exactly as other instruments I got. Then you can compare to speed with others in forums:
https://youtu.be/qbxA0XPbl6w

I have tried to measure on my Singer 201k. With a loose black V-belt, it runs 920 SPM max speed. When the V-belt tension is set, so the pulley just slips very slow, then the speed drops to 820 SPM. So the belt makes a significant power loss. The channel got some info on belts too.