Juki 341 issue

[the deacon]

Hi all,

An issue has cropped up with my 341 and I can't figure it out. It kind of appeared after a month of down time for the machine. Thought it might be a lubrication issue, so I oiled all points to no effect. I don't see the needle striking anything. The seize up seems to happen on the up stroke of the needle, I can "push" through it if I turn the belt pulley.

Any thoughts?

Thanks.

 

[Wizcrafts]

Can you remove the feed dog shaft and see if that frees the action? If so, the clearances have changed due to the weather and the shuttle is hitting the feed dog mounting bracket. It could be either the feed dog bracket and its mounting bar on the bottom, ot the shuttle drive gear or its shaft position under the arm. Those shafts are positioned and tensioned by tapered screws on the ends.

These are not definitive statements. The binding could be internal. It might be weather related, or even due to a loose, backing out screw on a rotating part.

[Uwe]

You need to find out exactly why and where it binds. "Pushing through" on motor power is almost never a good thing on a sewing machine. Disconnect the motor and turn it by hand. It's only way to really feel the bind and debug it. 

I had one 341 class machine that had a set screw on the hook driving cone gear touching the opposing cone gear. Took me hours to figure out. 

[Wizcrafts]

3 minutes ago, Uwe said:

You need to find out exactly why and where it binds. "Pushing through" on motor power is almost never a good thing on a sewing machine. Disconnect the motor and turn it by hand. It's only way to really feel the bind and debug it. 

I had one 341 class machine that had a set screw on the hook driving cone gear touching the opposing cone gear. Took me hours to figure out. 

Exactly what I was thinking at the end of my suggestions. This actually happens more often than we anticipate.

[the deacon]

Thanks Wiz and Uwe,

Just to clarify, I never pushed through on motor power, (actually the motor couldn't push through). I manually turned with the wheel.

I'll pursue your recommendations and let you know what I find!

 

[Wizcrafts]

If you don't find any protruding set screws and the shuttle isn't hitting the feed dog bracket, check for some thread fragments that might be jammed in or under the bobbin basket. Also check for mice under the machine.

[Constabulary]

The first thing I would do is put back on the throat plate and make sure it is correctly installed and then make a Video again. Running the machine w/o throat plate the as you show in the Video will probably cause a binding when the "uncontrolled" bobbin case hits the bobbin case opener.

Make sure the little tab on the bobbin case sits inside the notch of the throat plate and then try again.

 

 

Edited January 10, 2018 by Constabulary

[the deacon]

Constabulary, the exact issue was present with the throat plate attached, i removed for the video it in case it was easier to see and diagnose.

With the feed dog shaft removed the issue persists.

Sadly I don't know what the hook driving cone gear looks like. Does anyone know where to find a parts diagram for this machine? The owners manual doesn't give good diagrams.

[Constabulary]

are you sure the tab was in side the notch? if not try it. Other than that I would also think it a set screw that blocks the hook. Seems gear #48 is not attached with set screws so check set screws #57.

EDIT:

You can downlaod the parts lits here:

Parts List Juki 341

Edited January 10, 2018 by Constabulary

[the deacon]

Thanks Constabulary.

Just looked and the set screws are well set. I did take out the bobbin basket and it caused the binding to go away. So must be something with the bobbin. Could it have been a bobbin case opening lever adjustment issue? Is there a good resource on how to dial it in?