Cylinder arm seiko LSC 8BHC

[Marievee]

Hi guys really need some help. I’ve been offered a seiko LSC 8BHC for £400 with a servo motor. The guy who’s selling it has no idea about sewing machines I have no idea why he bought it. He changed out the clutch for a servo and cleaned the machine. Now the bobbin thread is just bunching up under the fabric. I’ve looked for a manual online but can’t find one. Apparently it’s got a thread trimmer? How does this work?  Could the bobbin thread problem just be a tension problem or could it be more serious?  Really need some advice before I buy this. I’m a bag maker so a cylinder arm would be great. 

[Tejas]

Link to download Instruction Manual

https://www.supsew.com/wpfb-file/seiko-lsc-instruction-manual-pdf/

 

[DonInReno]

#1 rule of thumb:   Any machine that can’t be shown to sew correctly is at most worth half that of a fully functional one.  

#2 rule of thumb:  see #1.

Different machine/fabric/needle/thread combinations rely on hand tensioning thread at the beginning of a stitch to varying degrees.  If thread is held properly then the problem might be a lack of proper upper thread tension - simply pull on the thread near the needle with the presser foot down - if there is no resistance then something is wrong in the thread path or tensioner.

If it’s not operator error and upper thread tension exists then there are issues below in the thread path - how the hook makes a loop and releases thread in advance of the next cycle.

If it’s been messed up for a while, maybe even before he had it, chances are a number of well intentioned people have been turning screws making things worse -literally a dozen things may be completely out of adjustment at this point - not just the original thread issue.

If you hand turn the machine and take a video showing the hook making a thread loop then we can better help you.

Also, look over any used sewing machine carefully with a string flashlight - especially if it’s not working correctly.   Look for cracks, welded parts, anything that looks out of place.  The hook should be rather sharp and smooth.  Tension disks and everything in the thread path shouldn’t have deep wear grooves from thread.  Look for stripped out screws, broken screws, cheep replacement parts, obvious signs of impact inside and out.

Just remember if it was easy to fix he would have already fixed it - he’s given up and is passing his troubles onto you.

Best of luck - hope it all works out well!

[Marievee]

Thanks for that. I think you’re right if it could be fixed he would have fixed it himself but he is a bit clueless. If I buy the machine if there is a problem do you think I could get it repaired? I can’t find the exact model instruction manual and the threading combo loos a bit different 

[oldtimer]

If the thread is bunching up under the material it is the top thread tension that must be tightened

 

[DonInReno]

If you don’t enjoy working on machines yourself then paying someone to sort it out will add up quickly.  Would you buy a car for cheap that doesn’t run hoping to fix it, or have it fixed?  If so, then yes buy the sewing machine and hope for the best.  If it sounds silly to buy a car that is a fixer upper then you won’t be any happier fixing a sewing machine.

 

[Bert51]

If he does not know the machine, I would say it is not threaded correctly, if you download the manual and look at page 7 figure 7 it will show you the correct threading for that machine.

I think that the top tension is causing the problem.

Bert.

 

[Marievee]

Thanks everyone x