The number of yards on a bobbin can be estimated/calculated by a thread manufacturer. This information is sometimes found on their website based on the standard sizes of bobbins L and M (Innovas use the larger M size) and the weight/thickness of the thread. Or you can guess based on what their pre-wound bobbin holds if they sell a pre-wound in that thread brand and weight.
For example: Fil-Tech Hab+Dash Glide, Magna-glide delight bobbins (40 weight) list on their website that they have 132 yards on them. It is fair to assume, you should be able to get about that, more likely a little less on your own winder.
In most cases, professionally wound pre-wound bobbins will have more thread on them because of the precision machinery that is used to wind thread onto the bobbin core (or plastic bobbin) and the consistent tension that is applied throughout the winding process according to the folks at Superior Threads. Your L and M bobbin winder can have varying yards per bobbin compared to pre-wounds or even compared to your friends due to tension settings or other set-up variables.
If you are a numbers/data person or simply just curious, on your Innova machine with Lightning Stitch you can use the bobbin percentage indicator to calculate exactly how many yards are on your own home-wound bobbins.
1. Wind a full bobbin and put this bobbin into the machine.
2. Set your starting number:
For M Series machines: Press and hold on the bobbin percentage indicator in the lower left corner of the LS screen on the front of the sew head. Tap the white number box, the numerical keypad will pop up.
Enter a very high number, ex: 800. More yards than you would ever expect to be on a bobbin. Keep note of this number. Hit enter. The percentage should have popped back to 100%.
For classic machines: Click set up in the lower right corner of your LS screen on the front of the sew head, a pink icon.
Look for Bobbin Length, the third opening down. Press and hold the number there until the numerical keypad pops up.
Enter a very high number, ex: 800. More yards than you would ever expect to be on a bobbin. Keep note of this number. Hit enter.
Click Main, purple icon at the bottom of right of your LS screen to exit back to the main screen.
In the upper left corner of the LS Screen, click the yellow letter “R” under the word Bobbin to reset the percentage to 100%.
3. Stitch away! Stitch until you run out of bobbin thread being careful not to pull way too much extra thread (full yards), and not to hit the reset button on the screen for the bobbin percentage.
4. Note the percentage displayed. You can use this number to figure out what the yardage is that would be left on your bobbin if it were a bobbin that was 800 yards.
5. Using that number subtracting it from 800 gives you the yards used/stitched.
LET'S TRY AN EXAMPLE:
We started with 800 yards, and when we finished our quilting, we still show 88% of our thread is available.
Multiply 800 by 0.88 to give you 704.
Subtract these 704 remaining yards of thread from the original amount of 800 and you can easily see that you have used 96 yards of thread.
A fast and fun way to calculate this is to use this calculator website: https://percentagecalculator.net/
If we put in 800 to start (in the machine), when we ended the percentage indicator said 88/88%.
Go to that website and fill in the blanks for “What is __88__% of __800__?” = 704
800 – 704 = 96 – therefore we have used/stitched 96 yards of thread.
You can also use this number to estimate that since you used 96 yards of bobbin thread, 96 yards of top thread was also used. For how ever far you made it through that quilt/pattern/pantograph you used 192 yards of thread. Given this new number, and the total number of bobbins you used for the quilt, you could now reasonably guess how much thread you would be using from your cones for that size quilt with that density of quilting.