Tension issues with Artisan 618

[alex11]

Hello,

I just recently got my first industrial machine -- a used Artisan 618-1SC. I'm just testing it out with leather, and am having problems with the tensions. Specifically, my bobbin tension is as tight as possible, and my upper tension is as loose as possible, and yet I'm still getting the bottom thread showing.

• The bobbin tension is so tight that the thread barely comes out when bounce it like a Yo-Yo (the technique I've seen in a lot of videos as a way to tell the correct bobbin tension)
• The upper tension is so loose that any looser and the knob would come off
• I'm using 5-6oz bridle leather; a Groz-Beckert 135x16TRI size 20 needle; and size 92 polyester thread. See attached photos for the issue
• I went through the machine manual and checked that all recommended adjustments are within spec (they are).
• I believe I've threaded the machine correctly, based on the manual and a youtube video. In particular, the upper thread is correctly going through the thread controller disk, and I threaded the tension disc with the presser foot up (and made sure the thread seated fully in the disc)
• I've removed the bobbin spring and cleaned the area with isopropyl alcohol. I also re-bent the spring so that it applies tension well.
• I've also noticed that when I do a back-tack using the reverse lever, the stitch gets a bit loose

As it is, the tension balance is not terrible -- I could live with it. But it seems wrong that the bobbin tension is at its maximum and the upper tension at its minimum. With this setup, there would be no room for adjustment at all!

Can anyone give some advice about what else to check?

Also, is there a dealer that supplies parts for this machine? I tried emailing Artisan but haven't heard back

Thanks!

Alex

[Sonydaze]

When you fully raise the presser foot, does the top thread pull through fairly easily?

[alex11]

3 minutes ago, Sonydaze said:

When you fully raise the presser foot, does the top thread pull through fairly easily?

Yes -- it doesn't take a lot of effort to pull the thread when the foot is up. When I pull, the needle bends a bit, but not too much.

[RockyAussie]

If the top thread does not seem overly impeded coming through anywhere I would take of the top tension discs and make sure there is no little sharp bits that could be making it drag. A fine sand and polish can help as these discs dont rotate around and the one spot is all it takes.

[alex11]

38 minutes ago, RockyAussie said:

If the top thread does not seem overly impeded coming through anywhere I would take of the top tension discs and make sure there is no little sharp bits that could be making it drag. A fine sand and polish can help as these discs dont rotate around and the one spot is all it takes.

I disassembled the tension discs. They were dirty, so I cleaned them with isopropyl alcohol. However I couldn't feel any burrs anywhere that the thread contacts.

I also disassembled and cleaned the thread controller disc, as much as possible (the two plates can't be separated). I noticed there's a slot where it screws into the machine body, so when I reassembled it I angled it so the thread is closer to the tension controller spring. I also kept the controller knob loose, so the controller spring could move more freely.

This seems to have improved the tension balance a bit. However I still have to have the bobbin tension extremely tight and the upper tension as loose as possible -- which in my naive opinion doesn't seem right.

Edited May 19, 2017 by alex11
clarifying

[RockyAussie]

I can only think to suggest loading a couple of pics of the thread path and close in on the tension discs and spring. Also which direction does the bobbin spin when you pull thread through it?

[alex11]

37 minutes ago, RockyAussie said:

I can only think to suggest loading a couple of pics of the thread path and close in on the tension discs and spring. Also which direction does the bobbin spin when you pull thread through it?

Here are some pictures of the thread path and the bobbin. Click the thumbnail for high-resolution versions.

BTW, thank you both very much for helping!

 

[Sonydaze]

The bobbin appears to be in correctly.  I would try not going through all three holes in the two thread guides, thread them only using two holes.  It is difficult to judge the scale, but the thread looks heavy for 92 poly, I have had a mislabeled cone of thread before.  Perhaps try a larger needle? 

[RockyAussie]

I think Sonydaze is correct about the going through the 3 thread holes being too much.Being so close together they would create a lot of drag without the tension discs and I cant say I have ever needed to run the thread through so many holes before.Bigger needle should not help though as that should only make it easier to pull the knot through even further. In your second picture the thread appears to be behind the disc guide for the thread tension return spring which would play havoc but in the other pics it looks like you may have it back into correct position.Maybe it works now? For what it is worth when the bobbin has that little thread on it it can start to get a little looser as well. Is the bobbin a good fit on its shaft as picture 9 makes the bobbin look like it is loose enough to touch the case edge. Hope there is an answer in there somewhere for you.  Regards Brian

[Wizcrafts]

I keep my long body walking foot machine loaded with #92 bonded thread and a #19 needle. I only use a #20 in webbing, for the bigger hole it pokes. If you can get a pack of #19 needles the tighter hole will help balance the tensions better.

According the this thread and needle chart, the diameter of #92 bonded thread should be .0133" (.337mm). Your thread looks bigger to my eye.

Sometimes, if a machine's timing is too far advanced, there will be extra tension on the top thread as it gets pulled around the bobbin case. This is usually indicated by a snapping sound as it goes around and up. The same thing can happen if the machine is internally belt driven and the belt is off by one cog or link on the bottom.

Another thing I've found that can interfere with the top tension is the tension and travel of the check spring. If the travel is too long, or the tension too high, it adds to the overall top tension. A hopping check spring on the take-up cycle can be an indicator that the hook timing is off.

[alex11]

I think I've got it! Many thanks to everyone!

I did each of these one at a time, and each one seemed to get me a bit closer:

• Rethread the upper using only one of the holes in each thread guide plates
• Wound a new bobbin full with thread, and with much higher tension on the winder (I didn't realize the winder tension disc was very loose before, so the winding was previously not tight or neat)
• Used a #18 needle (I don't have any leather #19 needles)
• Repositioned the thread controller to minimize the distance that the thread controller spring travels

A few other notes:

• Part of the issue may be how sensitive the bobbin tension adjustment is -- I didn't realize how big a difference a small turn makes!
• I measured the thread with a micrometer (the best I could manage -- it's hard to measure without compressing), and it was around 0.33mm -- so it's possible that it's #92 or #138. It is a brand new spool of A&E #92 from threadexchange, so I hope it's not mislabeled!
• The bobbin tension still seems a bit tight, but I can live with this. I'll double-check the timing as Wiz mentioned
• The bobbin is a bit sloppy in the case, but no different than the other various bobbins that came with the machine. I'm not sure how much tolerance is allowed. I'll probably just get a new set of bobbins, bobbin case spring, etc just to be sure