What am I doing wrong?

[ruffwerkz]

Hi All,

So I've had the Cowboy CB4500 for more than a week now and I'm pretty happy with it. I've been using the machine everyday on all of my orders. Today while I was using it to stitch some collars I noticed that one of the stitch was raised. Why did this happen? I'm pretty sure it's user error, but I'd like to know what error I made. 

For a background on what I did to the machine. I recently replaced the presser feet spring to a lighter one and I'm using a 25 needle with  #277 top and #277 bottom. I have the top thread tension set to just (2 screw thread showing) which I use when I'm stitching 1/8" thick (4-6 thread showing) when I stitch anything thicker. The bottom thread tension doesn't get adjusted but I do change the loop count depending on how thin the leather I'm stitching. The presser feet tension right now is backed up for a lighter setup so I don't get marks (the lighter spring does help a lot though). Seeing that I'm a novice, I'm quite certain that I'm doing something wrong. 

I looked up skipped stitches but this one doesn't look like it skipped, more like loose to me. Should I increase the tension on the presser feet? Upper thread tension? 

Thanks! 

Jomar

 

[Uwe]

"Stitch happens". Whatever you did when that stitch happened, don't do that.

But seriously, perhaps it was some anomaly/lump in the thread that caused it to be pulled up a little as the needle ascended. Make it happen more than once on some test scrap pieces and whatch/listen for anything unusual and inspect it closely afterward. It's hard to suggest, let alone pinpoint a cause remotely from just one occurrence, when the other stitches look damn near perfect. 

Sew slowly enough to notice this right away and stop, to correct or figure out what was different or what went wrong. 

[ruffwerkz]

Hi Uwe,

Thanks for the reply. I was actually stitching slow (about 660 on the FS-550 servo dial) didn't notice it happening since I was focusing on keeping it in line. I'll follow your advise on some scraps and see if I can recreate it again. I am using a cowboy brand thread and at the moment don't have anything else. 

Jomar

[gottaknow]

Usually when I see this condition I tighten both the needle and bobbin tension, a bit at a time until it stops. It tends to happen more on "sticky" materials. Leather, waxed canvas, Tyvex, cordura, etc. At needle rise, the loop remains a bit too large and results in extra thread. A little stiffer check spring can help as well. If it happens more often, it's usually insufficient feeding due to improper feed dog height and/or foot pressure. This is more prevalent on needle feed machines. 

 

Regards, Eric 

[ruffwerkz]

An update on my loopy situation.  I haven't been able to replicate the "error". I had 5 work orders and did a bunch of scraps as well...slow, semi fast and some fast sewing and could not get it to do the same thing. 

 

Thanks Eric for what I need to look out for, but at the moment I'm going to let it be until it happens frequently (hopefully not). I did tighten the tension on the presser feet a bit more and will just have to compromise on some marks. I'll play with it again when I don't have any orders to finish up since I have it dialed down to how I like it. 

Jomar

[CowboyBob]

Jomar,

 I leaning like Eric towards foot pressure..I think your pressure was just loose enough that the leather lifted as the needle pulled up.These types of machines with walking feet always will mark some & some leathers mark easier than others.If needed the marks can be rubbed out by a spoon.

[ruffwerkz]

Hi Bob, 

 

Thanks and yes I just increased the pressure on the presser feet last night and so far everything is running smoothly. 

Jomar