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Stitch length measurement unraveled

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    Stitch length measurement unraveled

    Stitch length measurements and settings are called out differently depending on the sewing machine.

    Most of us probably grew up using sewing machines where the stitch length setting is measured in stitches per inch (SPI). These were the good ol’ Singers and some of the Japanese machines. This probably the most familiar method to most of us. The other setting method is the metric number common to the European machines of any vintage, some vintage Japanese, and the newer computerized machines where the setting is shown as a number in millimeters (mm).

    The “American” system (SPI) measures how many stitches are in an inch. The metric system measures the length of each stitch.

    There’s times when some may wish to have a conversion to the system we’re more familiar with. It’s usually when we get that new machine and aren’t really sure what the number on the screen is telling us. We might have a favorite SPI number we use for various tasks and want to duplicate that length on our newer machine. Or maybe we want to convert the other way, because we acquired a vintage machine which isn’t called out using the same measurement. Or maybe we’re just curious when our newer machine defaults to a metric stitch length and we just want to know how many that is. So let’s do it.

    Remember one thing- there are 25.4mm (millimeters) per inch.

    To convert SPI to metric- 25.4 divided by SPI = mm.
    To convert metric to SPI- 25.4 divided by mm = SPI

    I hope this isn’t too confusing.
    You gots to risk it to gets the biscuit-

    Oh my! That's a lota work! I like to eyeball it.
    I just know I like 15-18 stitches per inch dispite the fact they are harder to unpick. I like my stitches to stay put. On my newer Juki, I use 1.8 or 1.5.
    However, when quilting on a vintage machine, I go as long as it gets, and on my Juki, I do 3.5 which seems to be close.
    Pieced By Me! :icon_wave:

    Pre-cut Yardage Chart