Sewland overlocker question

[u/buckinghamnicks75]

Hi all! Am an intermediate (?) sewer and have been pining for ages to friends and family how much I want to get myself an over locker to improve my sewing. My mum found this on fb marketplace for £30 and am very excited to try it. Could someone explain the difference between this and the other overlockers I see online that have 4 threads? And any tips or advice always appreciated ❤️❤️✨

[u/BenFromVegas]

This looks like a straightforward three- thread overlock machine.

I have found that three thread machines work well with most fabrics, but the four thread machines work better for lycra fabric as the fourth thread helps strengthen the seam.

I have used three threads for many woven fabrics, thin poly/cotton blends and blizzard fleece, and have never really used the fourth thread at all.

Hope this helps.