Bobbin tension I can't find a screw to adjust the bobbin tension on my machine (singer, 5805C) The thread is in big loops =(  I just paid $80. to have the darn thing cleaned and tuned up!!!!! Any way enough about me =) Can you give me any pointers?

K McMurdo's answer is correct.
Further: you will need to balance the tension between the top and bottom thread. After LOOSENING (anticlockwise) the screw on the bobbin case with a good quality thread wound on the bobbin. pull it out to see that it is tightened slightly. Put the same thread on the machine and carefully thread up the machine. A very high proportion of bad stitching problems is caused with incorrect threading of the machine. Set the machine tension at a mid point and slowly pull both threads to approximate that the tension is approximately equal on both. Keep the presser foot up while doing this. If the bottom thread keep adjusting the screw on the bobbin case until you get the threads roughly even. You can then try sewing and adjust the top thread until you have the stitch loop bedding in the fabric. It is essential that you have a needle that is appropriate to the fabric and thread you are working with!

Best Wishes, Ray

I am not sure about this particular machine but in most machines there will be a nob on the front loose low numbers like 0 1 -2 work well on number 3. If the nob is not on the front check and see if it is on the side.

bird nesting ( big loops under material) is from the needle thread tension being too loose
thread the machine as if threading the needle but before threading the needle pull on the thread , there should be resistance to thread feed
if not the tensioner plates are not adjusting properly

Generally, thread tension should be adjusted at the top thread. Only in extreme cases should the bobbin tension be adjusted.

http://www.singersewinginfo.co.uk/tension

How to Adjust Tension Sewing Machine

Liz Kettle adjusting your bobbin case tension 1 wmv

Fixing Top Load Bobbin

Sew What Up View thread Singer Stylist 513 threading correctly

sounds as if it has insufficient top tension, clean between discs then re thread with presser foot down

try adjusting the top thread tension to one number higher at a time until the stitches start looking right

also check with singer customer service for a instruction manual

Hello,

If you have Increased the upper thread tension on your machine, try these solutions.

* Decrease your bobbin tension if your sewing machine allows you to adjust it. Consult your manual.

* Re-thread your bobbin, It may be threaded incorrectly.

* Reinsert your bobbin, It may be inserted incorrectly.

* Change your thread. If your upper thread and bobbin threads are different types, try using the same thread for both.

I hope this helps.

Now you need to adjust the tensions, make sure you thread the machine with the presser foot up, top tension should be about 4 or 5, you should be able to pull the bobbin thread through with slight resistence, if it is too tight slacken the large screw on the bobbin case about a quarter of a turn at at a time anti clockwise and test sew until you get it right, do not use very thick threads.

pucker is caused by too loose or, to tight adjustment of: the thread tensioners both the bobbin tensioner and, the needle tensioner need to be adjusted: to adjust the needle tensioner turn the side knob clockwise is tighter counterclockwise loosens; the bobbin tensioner is a tiny screw on the bobbin holder adjust both tensioners until your stich loops' both top and, bottom are tight but, the machine does not break the thread

Okay it is the tension scrow on the bobbin. There is a small screw on the bobbin and by tightening it it gives you more tension on the bobbin.