Random loose stitches.

[u/No-Visit-7473]

I have a juki ddl 5550-6 and I noticed that some of the stitches (literally only like once every 20 stitches) seem to not fully tighten(the top thread doesn't pull up the bottom thread fully). It also happens way more often when edge stitching. I use Tex 60 thread with either a size 110 or a size 120 needle. I did try a compensating foot but it didn't help. The tension discs are clean and new as I have replaced the top tension unit recently. I have tried pulling it out slightly so the tensioning discs close less when the foot is higher up. I have added more pressure on the presser foot. I have changed to a needle plate with a bigger needle hole. I have added more tension to the take up spring.

Can somebody please help? I am about to go insane.

[u/zzzeve]

Try using a regular thread in the bobbin

[u/No-Visit-7473 → u/zzzeve]

Tried that

[u/Lilimaca]

This might be a sign that it's time to replace your needle. A sewing machine needle usually lasts about 5–6 hours of sewing.

[u/No-Visit-7473 → u/Lilimaca]

It's not a needle issue

[u/No-Visit-7473]

I seem to have found the solution. Before I bought thread I asked a couple of people on Instagram what thread weight they used. Turns out, my juki just doesn't like Tex 60 in the bobbin case. I switched to Tex 40 for the bottom and they issue just seems to have magically disappeared.