What is the right bobbin thread tension?

[Pintodeluxe]

I like low tension sewing, so I set my bobbin tension fairly light.  Like pulling dental floss from its container, or maybe a little more tension than that.  

That way you won't have to use tons of upper tension to balance the stitch.  

[DonInReno]

3 hours ago, KathyBrown said:

  I was hoping that someone might have a suggestion for a starting point for an industrial walking-foot machine sewing leather???

A drop test/tension adjustment, with an industrial large bobbin case produces about 28g of tension - around the weight of five US quarters.

Unlike fabric which allows little resistance to the take up of thread , leather requires a large enough needle to make a path for the thread to pull up into the leather.    If the needle is on the small side and upper thread meets too much resistance, it can appear that the lower tension is too tight when it’s actually correct.

Upper tensions can be quite high and it’s not uncommon to have an industrial originally set up for fabric sewing to require a heavier/thicker tension spring.

[Gymnast]

23 hours ago, KathyBrown said:

Has anyone used a TOWA bobbin gauge?  Pretty slick.  I have a longarm quilting machine (in addition to my other machines, one of which is a Consew 206rb5) and it is helpful, as I change types and weights all the time.  I was looking for gauge settings recommended for my Consew but all I can find is the drop test, of which I have found at least three ways to do it.  I have just been working on moosehide slippers and have been fighting the tension which feels really tight.  Being a retired physician, I like precision - reproducible numbers rather than hammers or "it just feels right".  I was hoping that someone might have a suggestion for a starting point for an industrial walking-foot machine sewing leather???  It appears to be very different than for my longarm.

I think the Towa bobbin gauge is too expensive and over complicated. Its simpler and cheaper to use spring dynamometers, and they can measure the thread tension in more ways and be used to measure needle thread tension as well. Last time I looked for these dynamometers you could get them for about $1.5 each via Aliexpress from China. I would choose to get three types, 0-1 N, 0-5 N and 0-25 N. I prefer them over digital types, because you can get a better idea of the tension variation. This a short video that shows how these gauges look like:

 

[Gymnast]

I just saw two beginners having problems with thread tension in this forum. And it can be hard to help them when many things can be wrong. But thread tension can be quite easy to measure for a beginner and then this problem will be almost fixed. All the old guys in this business can just feel that the thread tension is right and adjust it according to that.

Lately I did a video about ways to adjust bobbin thread tension:

 

[kgg]

3 hours ago, Gymnast said:

But thread tension can be quite easy to measure for a beginner

I particularly liked the video at about the 4:30 mark showing a excellent visual of the drop method of adjusting the bobbin tension.

kgg

[toxo]

Whilst we are talking "the right bobbin tension", Take a look at the maestro Cechaflo deliberately putting the tensions out of whack to create a stunning effect. If you don't want to be mesmerised by his precision go to around 8 mins.

 

[Constabulary]

Ha - way cool! So having too much top tension now is a kind of art work. Very impressive - things like that would never come to my mind. THAT GUY IS A GENIUS!

[toxo]

3 hours ago, Constabulary said:

Ha - way cool! So having too much top tension now is a kind of art work. Very impressive - things like that would never come to my mind. THAT GUY IS A GENIUS!

He certainly is Folker. I can watch him all day long.

[Gymnast]

Interesting and very decorative piping. 9:47 Cechaflo show two synchronized seams quite close. Can you figure out how he managed to sew that?

Normally double needle machines got higher distance between seams, and I guess, that it is not sewn with double front loaded needles.