Thank you for watching and for your feedback, Mary! -TB

Hello! All purpose sewing thread is best and is usually a 50wt thread. Thank you! -MM

Hello Maghie! Yes, all type of fabric can be used with any Singer Heavy Duty machine. Thank you! -MM

Hi! Tension is used to form a stitch. Normal tension, that was mentioned in the video, is balanced. Normal tension is used for your all-purpose sewing thread and your all-purpose stitches, like the straight stitch that was used. Tension can be adjusted if you want to work with specialty thread, or create a different look. The higher the tension (bigger number) it will pull the bobbin more to the top. The lower the tension (smaller number) eases the tension, so the thread is pulled more by the bobbin to the underside. Here is an example: if you wanted to do a decorative stitch, you want the top side to just show top thread, you may not want it balanced. You can turn the tension to a smaller number, that will "pull" your top thread slightly more to the back. The normal settings are shown with the line connecting 3-5. I suggest grab some scrap fabric, and experiment. It's easy to put it back to the normal setting. Thank you! -TB

Hi! We currently do not carry the SINGER Denim, but if you follow the link you will find more of our SINGER Heavy Duty machines that have many of the same features: www.singer.com/machines/heavy-duty. Thank you! -TB

Can this machine take a size 16/ 100 needle?

@@IEXECUTIVE yes, this machine can take a size 16/100 needle for denim sewing. There are also denim needles that are idle for sewing with denim materials. Thank you -MM

@@SingerSewingCompany Does this Singer machine or the Heavy Duty 5523 and 4423 machines (or all of the above) have the speed and power to perform the stitch on denim as shown in the video link from the 3:40 mark to 4:40 kzfaq.info/get/bejne/euCKq7enzJnSp6M.html ?

@@SingerSewingCompany what would be the equal to this model?

Hi Marcia! I'm sorry to hear that. Your machine should have come with a pack of needles, they just might have been different because this specific Heavy Duty machine in the video was a Denim Heavy Duty, which is currently no longer in production. If you have any further questions or concerns, please reach out to our Customer Care team at 1-800-474-6437. Thank you! -TB

@@SingerSewingCompany thanks for reaching out, there’s was a package of needles but it was different from yours. I’ll call anyway.

Hello Abby! Thank you for watching! Can you elaborate more on the "chain stitch" you are referring to? Thank you! -MM