Foam (straps) + Juki = fail

[u/ruckusmountaingear]

Hey all. I’m hoping someone has an idea I can’t think of to troubleshoot this.

A few weeks ago I busted a needle sewing through some foam + Ecopak + spacer mesh. The needle ended up breaking my fixed counter knife (Juki 9010-SS) and messed up the timing. I was able to replace the part and got the timing dialed again and it’s been sewing fine except …

When I try to sew through foam + strap layers now, it immediately breaks the needle (keep in mind this was working before the first break). In addition to that, if I manually turn the wheel on this foam + strap layup, the needle thread starts but then the bobbin just doesn’t pick anything and no threading occurs. If I do the manual wheel on just a couple of pieces of scrap material, it works fine.

Could this be the presser foot tension needing to be increased? I’ve messed with tension settings through but I’m sort of spinning at this point.

Other troubleshooting ideas for potential mechanical issues?

Thanks jn advance 🤘

[u/nonoohnoohno]

Is your thread and needle thick enough for the foam? I suspect (in my very amateur opinion and experience, so grain of salt, and all) the needle getting deflected is *by far* the most likely culprit. Sizing up both needle and thread may prevent that.

[u/ruckusmountaingear → u/nonoohnoohno]

Needle is max what I can use on this machine (18). Thread should be fine using bonded Tex 69.

[u/QuellishQuellish → u/ruckusmountaingear]

Oh, that's probably your problem, throw a #21 on there. It ships with a #21 and #23 not sure why you think 18 is max.

[u/ruckusmountaingear → u/QuellishQuellish]

18 is max on the SS. The SH is the heavier duty version.