What To Do When Bottom Tension Doesn't Look Right

Mike’s Tech Tip

 Mike’s Checklist when bottom tension is not right.

1. Check the NEEDLE to make sure it is the Groz-Beckert size 18 gold colored needle.

 2. Reset the pre-tension knob to standard, flush with the center screw.

 3. Next, adjust the bobbin case backlash spring. Use the info in the backlash bulletin. “Please visit https://bit.ly/2kyTJ2u for reference.”

 4. Next, check the bobbin case tension by pulling on the thread as it comes from under the spring. It should pick up the bobbin case to standing Position; but not pull out of your hand. If you have thenew style bobbin case with the centering groove, pull the thread out of the groove to test the tension.

 5. Confirm that if you pull the thread out of the needle eye and tug on the thread, that the rotary disc turns, and the check spring pulls a little below the thread guide. Now remove the knob, lefty loosey.

 6. Put the knob back on one turn and set the mark on the knob 12 o’clock. Now tug the thread again and see if the check spring pulls down.

 a. If it does not pull down, it is too tight to start the process. Loosen the check spring by turning the center screw to the left counterclockwise 5 minutes; After each adjustment, pull on the thread to see if the check spring pulls down. Repeat until it does pull down, then back clockwise 5 minutes until it does not.

 b. If the check spring is too loose, start increasing the check spring tension up to 7 times in 5 min adjustments clockwise. Tug the thread after each adjustment.

 7. When it no longer moves, it’s the correct check spring tension. NOTE: if up to 7 adjustments did not stop the spring from moving...STOP and call ABM for assistance.

 8. Now balance out the check spring with a number of full turns of the tension knob to get the check spring to pull down to a bit below the thread guide.

 9. Test sew and adjust if necessary, with 5 min on the check spring center screw and a 1/2 turn on knob until stitches are pulled up. If it is still not pulling up after 4 such adjustments call ABM.