Consew 225 New Hook Issue

[Uwe]

I installed a new Hirose hook in my Consew 225 and went through the Navy Manual hook adjustment and timing procedure several times just to learn, practice and get as precise as possible. While the hook-to-needle timing seems very accurate and the machine makes a nice stitch something's not quite right. There's a thread popping sound with every stitch. I investigated and found what seems to me like the thread getting pulled a little too tight and too early. The thread gets pulled between the bobbin basket and the race for a brief moment. It almost seems like the pull-up level is a tiny bit ahead of everything else. I've checked my threading several times, too. I'm attaching a little video that will hopefully show what I'm talking about. I'm not sure how to resolve the issue. Perhaps one of you sewing machine whisperers have seen this before and will just know what to do. Any help is appreciated.

Here's the video link:

https://www.youtube.com/watch?v=cOo80Eenvuw

Edited September 7, 2015 by Uwe

[Constabulary]

Seems the curved piece thats is holding the bobbin case is missing the jutting tip. This tip prevents the thread from getting caught between hook and bobbin case.

Edited September 7, 2015 by Constabulary

[Uwe]

Upon further review it turns out my reference manual contained an error and I was adjusting the hook timing very precisely using the wrong information! After adjusting the hook timing using correct information, buttery smoothness ensued.

I had printed out page 12 from the US Navy manual from Keystone Sewing manual some time ago as a reference and never really questioned or cross-referenced the information on it. Alas, it turned out to be a bad reference in one tiny but important aspect. The Keystone manual page states twice that the needle bar should be raised "three sixteenth of an inch" from the bottom when aligning the hook. After doing further research it turns out that just about all other manuals and resources require the bar be raised by exactly half that amount - 3/32" - to set proper hook timing. This made all the difference in the world for my Consew 225 hook timing.

Having a nice, clear PDF manual created for military use seemed like a good idea at the time. Most sewing machine techs probably have that 3/32" number burned into their brains and never refer to a manual for it. Doing it "by the book" tripped me up. Lesson learned: make sure the book you're using is a good one.

Here's a picture of the Keystone manual page in question: