SINGER 3337 SIMPLE 取り扱いマニュアル

Stitches are formed when the upper thread 

and the bobbin thread interlock between the 

fabric layers. Stitching is well balanced when 

the needle thread appears on the top and the 

bobbin thread appears on the bottom. 

                                                                                  

 

 

The Thread Tension Dial has a range of 

settings between 0 and 9.  Most of your sewing 

will be done with your Thread Tension Dial set 

between 3 and 5. It can be adjusted to a higher 

number for more tension on the upper thread, 

if the upper thread seems too loose. It can be 

adjusted to a lower number for less tension on 

the upper thread, if the bobbin thread seems to 

be showing on the top side of the fabric. 

 

 

 

 

Thread tension can also be adjusted for 

various sewing techniques. For basting (see 

Appendix), you can loosen it to a lower number 

so that the stitches can easily be removed. For 

gathering, you can turn it to a higher number. 

 

 

 

 

 

 

3. 



 When you sew, if you see large loops 

on the underside of the fabric, this is actually 

an indication that the upper thread was 

not threaded correctly, as it has no tension 

controlling it. For information on how to correct 

this, see the Troubleshooting and Maintenance 

section of this manual. 

Surface

Reverse

side

Upper thread
Bobbin thread

Surface

Reverse

side

Upper thread
Bobbin thread

Surface

Reverse

side

Upper thread
Bobbin thread