Cb341 stitching question

[Tommy217xxx]

Hey everyone, I got a cb341 this week from Cowboy bob. I haven’t had much time to use it yet but I have run into a few issues.

The top thread keeps getting caught in the bobbin. It’s not constantly but more than I’d like. I used 2 different color threads so I could see what was going on. When I go to cut the thread, I usually had extra top threads to cut and then they are hard to pull out.

another question, does this sewing machine tie off the first stitch or do I do a few reverse stitches to lock it? 

[Hildebrand]

I can’t help on the thread issue but, yes you have to back stitch to lock the stitches. 

[Wizcrafts]

6 hours ago, Tommy217xxx said:

another question, does this sewing machine tie off the first stitch or do I do a few reverse stitches to lock it?

The machine is a lockstitch machine, meaning that the top and bottom threads are pulled up in a fist-like knot and into the material. The slightest tug on the top or bottom may pull the knots out and cause stitches to unravel. You should either reverse over the starting stitches, or sew all the way around and go over the first 4 or 5 stitches, or set the stitch length lever to the zero motion position and sew up and down in place about 2 or 3 times, then move on with the preset stitch length. Sewing in place requires a little more aggressive top tension to pull the knots up among multiple passes. Sometimes, just two hits is all it takes to keep the knots from coming out.

[Tommy217xxx]

Ok. I think I have the locking stitch figured out. Now I need to figure out the top thread getting in my bobbin.

[CowboyBob]

44 minutes ago, Tommy217xxx said:

Ok. I think I have the locking stitch figured out. Now I need to figure out the top thread getting in my bobbin.

Hey TJ,always remember to stop & start with the takeup lever all the way up,in the pic above it is down & that is why you have extra threads from the bobbin because when you stop with it all the way up it releases it from the hook.

[Tommy217xxx]

45 minutes ago, CowboyBob said:

Hey TJ,always remember to stop & start with the takeup lever all the way up,in the pic above it is down & that is why you have extra threads from the bobbin because when you stop with it all the way up it releases it from the hook.

Thanks bob. I’ll play with it more when I get home. It’s a great machine.

[Tommy217xxx]

Are these skipped stitches or are they loose?  I’m not sure how to fix it.

Edited 16 hours ago by Tommy217xxx

[friquant]

Skipped stitches are when there is a hole in the leather but no knot for that hole. That is, the hook did not catch the top thread and drag it around the bobbin. I don't see any skipped stitches in your photo.

What I do see is the vertical position of the knot varies from stitch to stitch. Needle size, thread size, material composition, stitch length, and thread tension all affect the vertical position of the knots. Usually the goal is to have the knot hidden somewhere in the middle of the material. Doing this reliably seems to be easier when the overall material is thicker, and when there are multiple layers involved. 

To start off your experimentation, get a feel for the range of thread tension offered by the bobbin tension spring---then choose a bobbin tension on the low end of the range. 

From there, experiment with different top tensions. Higher top tension will pull the knots all way to the top of the material. Low top tension will leave the knots all the way at the bottom of the material. Too low of top tension will leave loops of top thread hanging down below the material (sometimes the hook will grab these and your machine will bind.)

 

[Tommy217xxx]

9 minutes ago, friquant said:

Skipped stitches are when there is a hole in the leather but no knot for that hole. That is, the hook did not catch the top thread and drag it around the bobbin. I don't see any skipped stitches in your photo.

What I do see is the vertical position of the knot varies from stitch to stitch. Needle size, thread size, material composition, stitch length, and thread tension all affect the vertical position of the knots. Usually the goal is to have the knot hidden somewhere in the middle of the material. Doing this reliably seems to be easier when the overall material is thicker, and when there are multiple layers involved. 

To start off your experimentation, get a feel for the range of thread tension offered by the bobbin tension spring---then choose a bobbin tension on the low end of the range. 

From there, experiment with different top tensions. Higher top tension will pull the knots all way to the top of the material. Low top tension will leave the knots all the way at the bottom of the material. Too low of top tension will leave loops of top thread hanging down below the material (sometimes the hook will grab these and your machine will bind.)

 

Thank you for the advice. I’m gonna experiment with tensions and see what I get. My girlfriend has 3 long arm quilt machines and we’ve been feeling with tension for years.

[AlZilla]

Loose and inconsistent. Definitely something going on there. I'd do 2 layers to get a better idea how it's stitching.

I merged your 2 threads together since it's the same machine and continuation of the same basic problem.