Bobbin (Lower Thread) tension for Singer Inspiration 4210 machine?

I always use the drop test for machines with removal bobbins. I don' tknow what the 'actual value of thread tension' is supposed to be, I only know what it's supposed to 'feel' like :)

-Irene

Inspiration 4210

scale plate and

tension

bobbin cases,

does the manual not give any instruction ?

my somewhat educated guess is possibly... if the upper tension gauge was calibrated to match a drop case tension with your plastic bobbin case. I suppose you could test the "bobbin case drop tension theory" easily enough by setting the bobbin case tension by that drop method, then load up the machine with same thread loaded on the bobbin and then put a 80/12 universal needle (a middle range needle) in the machine and sew two layers of a medium weight fabric with straight stitch (SS). Adjust the the upper tension knob until you get balanced stitches.

Then the question is, what is the upper tension setting required to balance the stitches ? is it close to the middle range of the upper tension setting values ? Is the upper tension value near some pre-defined default value on the upper tension knob ? ( ie. some of my machines have a reccomended start upper tension setting for SS at 3 out of (0-9) some of my machines have no such reccomended start tension and then others have ranges )

if the upper tension value is close to some expected or desireable value then the drop test probably works for your machine.

It would be interesting to know what the weight of your plastic bobbin case is with a full bobbin and how close it is to the 27 grams ? I wish i could tell you the weight of a metal bobbin case ?

NOTE/aside .... the tension test method elaborated above is one way i have calibrated bobbin case tension on some of my machines for my personal usage needs. I can't remember who/where/how this method came to me but if you do not get any definitive answers on the

**default** bobbin tension setting for your machine, you can use that tension setting method as a way to calibrate your **bobbin case** tension to **your needs**.

So.... that would mean

(low/mid/high) there are a variety of personal calibration strategies you could use here. I use mid-range or slightly below mid-range of what i typically sew.

now the **bobbin case** would be calibrated to your usage or need

Or maybe i will get skewered or flamed by (alt.sewing) for suggesting such a scheme :)

hth robb

Irene,

Do you know of a web-site that details adjusting the bobbin tension with that method? Is that the methof that David Coffin speaks of in the SHIRTMAKING book? (If you don't have access to that book, I could scan those pages, I guess)

Is this something I should do on my (fairly) new machine?

Inspiration 4210

scale plate and

tension

bobbin cases,

FWIW I measured the weight of some of my drop tension (singer/pfaff/necchi) metal bobbin cases with a fully wound bobbin inserted and the values range between 10-15 grams HTH robb