Cobra class 4 Stitching issues

[Wykoni]

Recently purchase a cobra class 4, using 207 thread I am having a problem on front vs back.  Front is acceptable(light thread) but back is not(dark thread). Any help would be appreciated.

[Wykoni]

Just bought a new class 4 sewing machine and of course I am having issues.  The problem is stitching in the back, the darker thread.  The front seems to be ok, lighter thread.  Maybe I can get some help.  As you can see, the leather looks a little puckering up from stitch.  Any help would be appreciated.  

[RockyAussie]

The top picture is too small to make out the problem very well. Are you using a slotted needle plate without the feed dog? Or are you seeing loops of the top thread and your top tension needs tightening?

[Wizcrafts]

My first impression is the the thread is too large for the thickness of the leather. You can verify this by telling us what sizes the thread and needle are, plus the combined thickness of the leather being sewn.

When a new Cobra or Cowboy heavy stitcher is delivered to the customer, there should be a stack of leather 3/4 inch thick under the feet, or attached by trailing thread, sewn on that machine with #277 thread and a #25 leather point needle. It is your proof that the machine was properly setup and adjusted for thick work and thick thread.

Aside from the needle and thread possibly being too big for that thickness, another explanation could be excessive foot pressure for that leather thickness. When you got the machine from the warehouse, the pressure screw would be screwed way down, far enough to hold down a 3/4 inch stack of leather sewn with a loaded #25 needle. If your two pieces are only 12 to 16 ounces, the pressure screw needs to be backed out considerably. It only needs to apply enough pressure to prevent the leather from lifting as the loaded needle ascends, which would cause skipped stitches. Any pressure beyond that will needlessly force the bottom leather to be impressed into the elongated slot in the feed dog. It also causes unnecessary foot tracks to happen on the top grain. The "pressure screw" is on top of the head, directly over the bar to which the outside presser foot is attached. It is known as the "presser bar."

[Wykoni]

21 minutes ago, Wizcrafts said:

My first impression is the the thread is too large for the thickness of the leather. You can verify this by telling us what sizes the thread and needle are, plus the combined thickness of the leather being sewn.

When a new Cobra or Cowboy heavy stitcher is delivered to the customer, there should be a stack of leather 3/4 inch thick under the feet, or attached by trailing thread, sewn on that machine with #277 thread and a #25 leather point needle. It is your proof that the machine was properly setup and adjusted for thick work and thick thread.

Aside from the needle and thread possibly being too big for that thickness, another explanation could be excessive foot pressure for that leather thickness. When you got the machine from the warehouse, the pressure screw would be screwed way down, far enough to hold down a 3/4 inch stack of leather sewn with a loaded #25 needle. If your two pieces are only 12 to 16 ounces, the pressure screw needs to be backed out considerably. It only needs to apply enough pressure to prevent the leather from lifting as the loaded needle ascends, which would cause skipped stitches. Any pressure beyond that will needlessly force the bottom leather to be impressed into the elongated slot in the feed dog. It also causes unnecessary foot tracks to happen on the top grain. The "pressure screw" is on top of the head, directly over the bar to which the outside presser foot is attached. It is known as the "presser bar."

I am using 207 thread.  I do have some 277, the two PCs of leather are about 8oz together.  

[Wizcrafts]

2 minutes ago, Wykoni said:

I am using 207 thread.  I do have some 277, the two PCs of leather are about 8oz together.  

Your thread is too large for that thickness. Move down to #138 thread and a #23 needle. And, back off the foot pressure screw.

[Wykoni]

6 minutes ago, Wizcrafts said:

Your thread is too large for that thickness. Move down to #138 thread and a #23 needle. And, back off the foot pressure screw.

Will order some, let me ask you a question, I will be making holsters, the doubled thickness will be about 16 oz will the 207 be ok for that?

[dikman]

17 minutes ago, Wykoni said:

Will order some, let me ask you a question, I will be making holsters, the doubled thickness will be about 16 oz will the 207 be ok for that?

For holsters you should consider 277 to be the minimum thickness thread.

[DrmCa]

Are you using leatherpoint needle?

Is your machine new or used and where did you source it?

Please also post the picture of your needle plate and feed dog.

[toxo]

16 hours ago, Wykoni said:

Recently purchase a cobra class 4, using 207 thread I am having a problem on front vs back.  Front is acceptable(light thread) but back is not(dark thread). Any help would be appreciated.

Well done on making the leap to a machine Phil.

Hope to see mucho productivity from here on in.

[Wizcrafts]

15 hours ago, Wykoni said:

Will order some, let me ask you a question, I will be making holsters, the doubled thickness will be about 16 oz will the 207 be ok for that?

Number 207 thread is a fairly strong thread. I use it to sew suede lined rifle slings and guitar straps that total about 9 to 12 ounces. It can sew 8 ounces but it is a little tricky to hide the knots. These items don't place much strain on the thread; it just holds the layers together.

Handgun holsters are a different matter. The edge stitching isn't just holding layers together. It has to hold the shaped or unshaped product together under the stress of drawing and holstering a steel weapon. You want the strongest thread holding it together. I use #277 to hold holsters together. It is possible to bury the knots in 1/4 inch of veg-tan if you play with the top and bottom tensions. I assume you are making pancake holsters if they are only 1/4 inch thick. Most of our holsters run between 3/8 and 3/4 inch thick at the outer edge. There is a filler between the layers that positions the weapon. This filler can vary from 1/4 inch to 1/2 inch. Your Cobra Class 4 is fully capable of sewing 3/4 inch thick holsters!

[Wykoni]

1 hour ago, toxo said:

Well done on making the leap to a machine Phil.

Hope to see mucho productivity from here on in.

Thanks, hope your doing well, now just pulling what little hair out I have in adjusting this thing lol

[toxo]

2 hours ago, Wykoni said:

Thanks, hope your doing well, now just pulling what little hair out I have in adjusting this thing lol

It'll come. Just remember to not pull your hair out until you've got all the ducks in a row. Getting one thing right without the others being right will have you pulling your hair out. even that little spring thingy has an important job.

[JLSleather]

18 hours ago, Wykoni said:

Will order some, let me ask you a question, I will be making holsters, the doubled thickness will be about 16 oz will the 207 be ok for that?

Yes.  I often use 277 on holsters because the LOOK of the heavier thread is popular.  But I sew a good bit of holsters (and other 'stuff') with 207.  Lots o' folk say that 207 breaks too easily, to which I say - show me

That said, looking at your example I do not like HOLES that large.  This is another reason for using 277 thread, with a #24 needle ... I would prefer to use a #23 needle when sewing with 207, but for some reason #23 needles are tough to find for these machines.

 

[Wykoni]

On 11/9/2021 at 3:33 PM, toxo said:

It'll come. Just remember to not pull your hair out until you've got all the ducks in a row. Getting one thing right without the others being right will have you pulling your hair out. even that little spring thingy has an important job.

I can hand sew it or carve it but this sewing machine stuff is totally alien to me, your much knowledgeable about it.