Not sure what my problem is... any insight appreciated!

[RaptorBravo]

Hello! I’m having an issue when sewing leather with the wrong sides together. The picture is the bobbin side of the sewing. I’m not sure what my problem is exactly. Is it my bobbin tension? Or pressure foot pressure? Any insight would be much appreciated. I tried adjusting both but saw no difference. 

[DJole]

I'm sure our sewing machine experts will be along to take a look, but in the meantime, you could help them out by giving some information:
1) What machine are you using?
2) what kind of leather, and what thickness?
3) What kind of thread, and what thickness?

[Constabulary]

Beside the above mentioned important information my 1st try usually is:

Increase top tension or decrease bottom tension or try a larger needle.

But there are more things that could cause stitches like yours.

[Yetibelle]

here is the chart.

 

 

[Mark842]

Without any other information like machine, needle size, thread size, leather thickness my guess would be not enough tension up top. That being said, wrong size needle and or thread will do the same thing

[Uwe]

The real problem may be that @RaptorBravo doesn't actually say what he or she doesn't like about that bottom stitch line. 

[Wizcrafts]

A lot of newbies to sewing machines, coming out of hand stitching land, are used to the same stitch appearance on the top and bottom. They have trouble Grokking why the bottom looks so different from the top. They are strangers in a strange land until they come to grips with the fact that especially walking foot machines push down hard directly around the needle holes - causing the bottom leather to take the shape of the hole or slot in the feed dog or throat plate.

In order to obtain a top/bottom stitch appearance that almost matches hand stitching requires a needle and awl harness stitcher, like a Union Lockstitch, or Campbell Lockstitch, or Landis 3 machine. These machines have a jumping presser foot and needle or awl feed. There is no inside foot like on a compound feed walking foot machine. The wound from the stabbing top awl tends to heal as the awl comes back up, quickly followed by an ascending barb headed needle. I used to get very nice bottom stitches on the Union Lockstitch machines I owned and let go of. But, nothing I've sewn on beats a Campbell Randall for top/bottom stitch appearance.

[edwelld]

Hi all,

I'm a complete newbie to machine sewing, and I have exactly the same symptoms that RaptorBravo does. On the bottom side of the work the knots are just visible.

I have a highland GC2268 which is rated for 20s (138?). I am using Somabond bonded nylon 20s in both the spool and bobbin.

I have tried increasing the top tension, but can't get rid of the knots. In fact when the tension reaches a certain point, I get an "extra loop" in the bobbin - when I raise the foot and pull the work away from the machine it sticks as there are 3 threads coming from the bobbin. I cut the 3 threads and one is the thread coming straight from the bobbin which pulls freely, the other 2 are different ends of the same short thread - if that makes any sense. 

Not sure if this is a coincidence or is directly related to the increased top tension. I haven't as yet tried to adjust the bottom tension, as frankly I'm a little concerned about over tinkering without knowing what I'm doing!

If I use 40s thread (69?) in the bobbin the problem goes away; however as most of my projects will have both top and bottom visible I'd like to have the same thread (20s) if possible, even accepting that the stitching wont be identical.

Is it possible that certain makes of threads at the 20s thickness will just not behave nicely in the bobbin? The soma bond was advertised as top thread; It didn't occur to me that it might be literal.

hoping that one of you experts can help.

kind regards to all 

David

[kgg]

2 hours ago, edwelld said:

I have tried increasing the top tension, but can't get rid of the knots. In fact when the tension reaches a certain point, I get an "extra loop" in the bobbin - when I raise the foot and pull the work away from the machine it sticks as there are 3 threads coming from the bobbin. I cut the 3 threads and one is the thread coming straight from the bobbin which pulls freely, the other 2 are different ends of the same short thread - if that makes any sense. 

I think all you need to do is make sure the needle is at its highest point and hand wheel it a touch more. With some machines you will hear a slight click of the thread being let go.

2 hours ago, edwelld said:

I haven't as yet tried to adjust the bottom tension, as frankly I'm a little concerned about over tinkering without knowing what I'm doing!

To get the tension right on your bobbin thread in a flatbed machine and I am sure it would probably be similar in a cylinder machine what I do is: with the bobbin in the case but before it is placed in the machine. Pull out about 6 inches and hold the end of the tread and let the bobbin / case rest flat in your other hand. If the bobbin spins easily in the case tighten the thread tension spring screw. If you can lift the bobbin and case off your hand with no thread coming off the bobbin then loosen the thread tension spring screw on the case. I like the bobbin case to stand up and the bobbin spin sightly not spin easily in the case. Also only thread the bobbin to about 80 percent and make sure it is inserted in the case so the thread comes off the bobbin in the right direction.

kgg

[JLSleather]

2 hours ago, edwelld said:

I have tried increasing the top tension, but can't get rid of the knots.

Have you tried one size bigger needle?  Sounds like you gittin' "stuck" at the hole on the bottom side.

 

[Matt S]

Hi David,

Have you tried reducing your bobbin tension? This would be my next course of action if adjusting the top tension didn't get what I wanted. Just a quarter or eighth of a turn anticlockwise at first. Then sew a few inches of scrap leather similar to what you'll be sewing "for real" and take a look. You may have to tweak your top tension a little again at this point to get it right. If that doesn't work, back the bottom tension off a little more and try again. You may be able to find a "happy medium" which tensions TKT20 and TKT40 thread are tensioned properly but there's an equal chance that you'll have to tweak the bottom tension a little each time you change thread size.

Next action, if that doesn't solve it, would be to go up one needle size, as JLS says.

Yes some brands of thread behave differently, and even some colours within the same brand. Black is notorious for being awkward as it is sometimes made by redyeing brighter colours, which can leave it... crunchier? Harder? Stiffer? Don't know what the right word is but essentially it is more reluctant to bend, which means it can cause problems in some machines, especially when forming a loop. I've got a few king spools of black nylon that's been sitting at the back of my thread shelf now, while I have never had a problem with Coats Nylbond in any colour. (It might help that I only buy it from sources that I know have a fast turnover -- nylon thread is apparently freshware. Saving a few quid buying "bargain" old stock or random-brand thread is often a false economy.) Somac makes good thread and it looks like they only started making Somabond 2 years ago so I wouldn't think it's a thread problem per se in your case.

[catskin]

7 hours ago, Matt S said:

Hi David,

Have you tried reducing your bobbin tension? This would be my next course of action if adjusting the top tension didn't get what I wanted. Just a quarter or eighth of a turn anticlockwise at first. Then sew a few inches of scrap leather similar to what you'll be sewing "for real" and take a look. You may have to tweak your top tension a little again at this point to get it right. If that doesn't work, back the bottom tension off a little more and try again. You may be able to find a "happy medium" which tensions TKT20 and TKT40 thread are tensioned properly but there's an equal chance that you'll have to tweak the bottom tension a little each time you change thread size.

Next action, if that doesn't solve it, would be to go up one needle size, as JLS says.

Yes some brands of thread behave differently, and even some colours within the same brand. Black is notorious for being awkward as it is sometimes made by redyeing brighter colours, which can leave it... crunchier? Harder? Stiffer? Don't know what the right word is but essentially it is more reluctant to bend, which means it can cause problems in some machines, especially when forming a loop. I've got a few king spools of black nylon that's been sitting at the back of my thread shelf now, while I have never had a problem with Coats Nylbond in any colour. (It might help that I only buy it from sources that I know have a fast turnover -- nylon thread is apparently freshware. Saving a few quid buying "bargain" old stock or random-brand thread is often a false economy.) Somac makes good thread and it looks like they only started making Somabond 2 years ago so I wouldn't think it's a thread problem per se in your case.

My solution for thread ( black for instance ) that doesn't do well on top is to use it on the bottom ( bobbin )  it has worked for me.

[dikman]

edwelld, what kgg said. I often get that same thing with what appears to be multiple threads coming up from the bobbin area, all I do is handwheel the pulley back and forth a little which releases the thread and it then just pulls out normally.

[edwelld]

Thanks all for the helpful responses.

Needle height was the issue with the "extra threads" - thanks very much.

I was using size 140 needles, I've order some 160s and I'll try the bobbin tension test suggested by Kgg.

Matt as you are UK based, I'm interested to know which thread you use and where you buy it from.

very kind of you all to take the trouble to help me out

kindest regards

David

[CowboyBob]

12 hours ago, dikman said:

edwelld, what kgg said. I often get that same thing with what appears to be multiple threads coming up from the bobbin area, all I do is handwheel the pulley back and forth a little which releases the thread and it then just pulls out normally.

If you stop with the take-up lever all the way @ the highest position it releases the thread from the hook.