You should choose the needle size according to the weight of the fabric you’ll be sewing.
To hem lightweight stretchy jeans, for instance, a size 90/14 needle should work just fine. In contrast, finishing a hem on men’s heavyweight utility jeans will probably require the 110/18 needle size.
You’ll also need to choose one of these two needle types to get through the entire process of hemming your jeans:
1 – Universal Needles sized 90/14, 100/16, or 110/18
2 – Jeans/Denim Needles sized 90/14, 100/16, or 110/18
How to choose between Universal Needles and Jeans/Denim Needles:
Universal Needles are useful when sewing a variety of fabrics from knits to wovens. These needles are labeled 130/705 H. Universals are not sharp enough to pierce numerous layers of fabric because they have a slight ball point. These types of needles are truly meant for completing a mix of different tasks.
Keep this in mind especially when it comes to topstitching the hem of your jeans. At the seams of your jeans, you will be sewing through either 6 or 9 layers of denim. This can put a lot of stress on a Universal Needle. If the denim is medium to heavyweight, you should opt for using Jeans Needles.
Jeans/Denim Needles are fantastic for hemming because they exhibit strong and sharp qualities. They are usually labeled 130/705 H-J. Although you can find this type of needle in sizes as small as 70/10, the larger needle size will work double duty when using a more durable thick thread, especially when you are completing the hem of your jeans with a topstitch.
Schmetz makes a variety needle pack which comes in super handy. It includes three of the sizes most readily used for jeans construction and hemming.
Which will you be using for your sewing project?