I ordered this model:


I downloaded this diagram to get a better idea of the parts(This from a different model but they share a majority of components): enter image description here

I'm just curious about the 1-10 knob on the back that puts a metal pad either closer or farther away from the device. I assume this varies the magnetic resistance

I'm also curious about the back-tension button. I see that when you tighten the screw the tension arm takes more pressure to pull down.

All-in-all, I just want to know how the knob on the back works in conjunction with the back-tension

Also, If you've used a Coil winding magnetic tensioner before, any info on its functions I would love to learn about.

I'm reaching out because there is basically nothing online about how these things work and all the labels on my tensioner are in Chinese so I'm clueless

  • $\begingroup$ Since the rubric has things like "wool clampinging" then I would find a different source to understand the function. $\endgroup$
    – Solar Mike
    Commented Sep 5, 2018 at 7:56
  • $\begingroup$ you're saying, that because it includes materials that are non-metal that this question can't be answered from a mechanical perspective? The wool is non-existent to the question I'm asking, which is when I add magnetic resistance in conjunction to back-tension; what happens? $\endgroup$ Commented Sep 5, 2018 at 8:04
  • $\begingroup$ I'm saying Find A Different Source... $\endgroup$
    – Solar Mike
    Commented Sep 5, 2018 at 8:15
  • $\begingroup$ I'm saying, others will listen and not find a meaningless edge-case that renders my question invalid...But you got the rep so why not down-vote? $\endgroup$ Commented Sep 5, 2018 at 8:23
  • $\begingroup$ I would expect that the tensioner operates through friction and that is why I suggested you found a different source so you may understand it better. I did not, and do not, see any reason to downvote. In fact, the item you link to says "mechanical tensioner" not "magnetic"... $\endgroup$
    – Solar Mike
    Commented Sep 5, 2018 at 8:30

1 Answer 1


I just bought the same tensioner. It took 20 mins (well, maybe longer!) to sus out but I reached the same conclusion. The back-tensioner is just an adjustable overtension alarm where the microswitch wires in to the coilwinder to stop it if the tension gets too high. The wire feeds in from below, normally off the wire drum standing on its end and through an upturned funnel guiding the wire. The wire enters between a couple of felt pads to stabilise it from its rotation off the wire drum, then around the magnetic tension spool to a free-wheeling pulley and thence over the alarm arm pulley to the coilwinder. The Magnetic tensioner works a bit like a car speedo, where a rotating magnetic drags a cup around against a spring the faster it goes. I guess by using a magnetic feild to add drag to the tensioning pulley, set by the big knob on the other side, it is a more consistant tension compared to using a slipping clutch based on friction materials.


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