Inconsistent tension- knots visible alternate top/bottom

[PigeonTreeCrafting]

I'm having an issue with my Consew 205rb. Or it may very well be my inexperience with sewing machines in general that is causing the issue.

I understand the concept of tension, and I have read many guides on the subject. If the knots are on the wrong side, increase top tension, if the knots are on the right side, lower top tension etc.

But what if the knots appear both on the top and bottom, sporadically? even when sewing in a straight line? And while I'm asking for help, why does curving the stitch create even more tension issues?

I'm willing to put the time in to learn, but I've been struggling for weeks trying to get my machine to work for me.

I'm using 135x16 size 23 LT needles with 135 top and bottom bonded nylon thread. I had tried running 92 on the bobbin, but it didn't seem to help and I much prefer the look of the thicker thread.

I attached a pic, just one small example of my frustration.

Thanks so much for any assistance!

[Uwe]

All the other stitches look really nice though!

I'd check the basics first, like proper threading and timing. Thread needs to come off the spool vertically, no at an angle to avoid snags. Make sure you can manually pull top and bottom thread very smoothly, without any snags. A poorly wound bobbin may cause uneven knots. Perhaps the thread comes off the spool in jerky fashion for some reason. Some spools are sticky or wound weirdly and cause snags. On a test piece with fingers far away from the needle, sew a stretch watching the thread path instead of needle area. Try some pre-wound bobbins if you can get your hands on some, just to compare to your self-wound bobbins. Listen for any weird noises when the offending knots happen. If something interferes occasionally with the smooth movements of the  machine, odd things start happening.  Does this happen when you stop/start the machine?

[PigeonTreeCrafting]

Thank you so much!

 

I will look over the machine in the ways that you've suggested.

And I am glad you think the stitches look good otherwise- I would agree! I can't wait to get it working properly so I can utilize and appreciate it fully.

It does this all the time. I am winding my own bobbins, so that is definitely a possibility. I'll look into all the things you suggested.

 

When you say there may be a timing issue.. That sounds a little overwhelming. Is timing something that can be adjusted relatively easily? 

 

Thanks again!

[Uwe]

One other possibility is that your foot pressure is a little too light. Your sample shows no foot pressure marks at the top at all - very pretty and usually what people want. Alas, the material must be held down by the presser feet while the knot gets pulled up into the material. Any small variation in leather density may cause trouble if the foot pressure is too light. The material may lift up as the thread take-up lever is trying to pull the knot up into the material and the knot stays at the bottom. The bobbin thread also goes slack a little bit as the material comes down again. The next stitch will have loose bobbin thread, causing the next knot to get pulled to the top on that stitch. At least that's how the sewing machine in my head works 

Your stitch samples shows this kind of knot pattern like ---v^v---- (where "-" means middle, "v" means bottom, "^" means top). Watch the material as you sew to see if lifts up occasionally. 

[Gregspitz]

I always go down one needle size and that has worked well

[Colt W Knight]

I have a 206, and I encounter this problem from time to time. 

1. Leather quality, belly leather is bad to do this.

2. The needle is 1 size too big

[PigeonTreeCrafting]

Thank you everyone! I haven't had time yet to play around with all the suggestions, but the foot pressure sounds like a logical thing to look at.

Regarding the needle size- I had hoped to find size 22 in that style, but 23 was the only thing available. Do you think that could really be the cause?

[Colt W Knight]

I recently tried to get a 22 LR and couldn't find one. 

I wouldnt play with other things till you've done the simplest thing first

[Gregspitz]

whatever you do only change one thing at a time so you know what works..thats what we do in Surgery!!

[spenzher]

Did you ever find out what was going wrong? 

[Gregg From Keystone Sewing]

Are you winding your own metal bobbins, or are you using a pre wound bobbin?  I've seen some pre wound bobbins that were so inconsistent that they would do this.  Wind a metal bobbin and see how it goes, if that's the case.

[Yetibelle]

Since I always forget I have this chart - Yours looks nice really, It can get much worse that that.  Sometimes I find a new needle helps, also let the machine pull the work.  It's very tempting to help it along as you guide it, that's when I find I miss a stitch or bend/break a needle. 

 

 

 

[Singermania]

I agree with the guys, the needle is too big, you've massive hole there.   A  140/22 should be heaps big enough.