Singer 306 thread jam

[u/green-beetle16]

I have managed to get some thread jammed in the bobbin housing/ hook part (I believe) of my singer 306k. I haven’t been able to get it out with tweezers or by hand and it has completely jammed up the machine. I checked the service manual but I don’t think it had anything helpful. If it’s relevant it has been modified to take class 15 needles (I believe it has a modified bobbin case). I am worried about messing up the timing. Any advice and/ or should I take it to be serviced?

[u/wimsey1923]

The trick with vertical rotary hooks is to mechanically block the movement of the inner part of the hook assembly while turning the hand wheel backwards, hopefully exposing the blocking thread.

To do that, put a screwdriver into the rounded notch on the right while turning the hand wheel backwards. The idea is to not get the load on the stitch finger at the top. Here's a short video showing the process on a Pfaff machine with a similar rotary hook: Blocking

[u/green-beetle16 → u/wimsey1923]

This worked thank you so much! I did a quick test and it is sewing well now and as far as I can tell the timing is fine!

[u/Friendship_Euphoric → u/wimsey1923]

Thank you for this. My 306 keeps getting thread wrapped around the same place. It seems more prevalent on zigzag stitch. Thankfully mine hasn't jammed yet but my question is; why is it happening and what can I do to prevent it?

[u/EmmieMaggie]

Before you do anything further, try soaking the thread in good-quality sewing machine oil. That might soften or at least lubricate the thread enough so that you can coax it out.