Need Help With Cobra Class 4 ... Stiching Issue

[RoosterShooter]

I have a 2 month old Cobra Class 4 that is skipping stitches every 30" to 31" on any material, any project, and every single time.  I can be using cowhide, horsehide, Chromexel, etc .... It doesn't matter.

I noticed the problem yesterday when I started sewing continuous stitches, whereas before I have always sewn 8" runs on holsters or small wallets. 

It does this every single time regardless of the material I am using.  Every 30" to 31" it skips a stitch. 

 

[DSloop]

Could the needle be getting hot and making the thread stick to it instead of being caught by the bobbin hook?

[Constabulary]

I don´t have a cobra but sometimes needle bars start rising a little bit. If it was me I´d check the NB height and maybe would try to lower the NB a little bit - maybe 0.5 -1mm.  Just to start with...

[Wizcrafts]

Have you tried a new needle? Is the needle inserted all the way up in its mount? It it aligned with the rib on the left and scarf on the right?

Do you have sufficient foot pressure to completely hold down the leather as the needle ascends? Lifting leather causes skipped stitches.

Timing  problem

The hook timing may have moved from thread drag, or the needle bar may have raised up due to impacts and loosened screws.

Power off before proceeding

1. Remove the top thread beyond the wax pot or top post.
2. Unscrew and remove the faceplate and set it aside.
3. Remove the bobbin and shuttle cover plate.
4. Set the stitch lever to the zero forward/backward motion position (rotate the hand wheel until it becomes zero feed).
5. Use the hand wheel to move the needle all the way down to BDC.
6. Continue wheeling slowly until the needle raises between 1/8 and 3/16 of an inch.
7. Shine a light inside and see if the tip of the hook intersects the center of the needle above the top of the eye, inside the scarf area.
8. If the hook and needle aren't intersecting above the eye at this point, determine if the needle is too high for the hook when the hook meets the needle position.
9. If the hook is under the eye of the needle, loosen the 2 screws securing the needle bar, lower the needle bar until the eye is about 3/16" below the tip of the hook and lock down the screws.
10. If the hook is arriving too late, it needs to be rotated clockwise to intersect the needle above the eye. If it is too soon, it needs to be rotated counterclockwise (looking at it) That is a matter for another reply and is fraught with room for serious error. It could affect the warranty.

Did you get a manual with the machine? Have you called or contacted Cobra about this problem? This would be a good time to do so.

[Bert51]

If all the above checks out okay,  check that your thread is coming off the spool smoothly and it's not getting caught any where.

That has caught me before, all my thread stands are extra tall.

Bert.

[RoosterShooter]

1 hour ago, Wizcrafts said:

Have you tried a new needle? Is the needle inserted all the way up in its mount? It it aligned with the rib on the left and scarf on the right?

Do you have sufficient foot pressure to completely hold down the leather as the needle ascends? Lifting leather causes skipped stitches.

Timing  problem

The hook timing may have moved from thread drag, or the needle bar may have raised up due to impacts and loosened screws.

Power off before proceeding

1. Remove the top thread beyond the wax pot or top post.
2. Unscrew and remove the faceplate and set it aside.
3. Remove the bobbin and shuttle cover plate.
4. Set the stitch lever to the zero forward/backward motion position (rotate the hand wheel until it becomes zero feed).
5. Use the hand wheel to move the needle all the way down to BDC.
6. Continue wheeling slowly until the needle raises between 1/8 and 3/16 of an inch.
7. Shine a light inside and see if the tip of the hook intersects the center of the needle above the top of the eye, inside the scarf area.
8. If the hook and needle aren't intersecting above the eye at this point, determine if the needle is too high for the hook when the hook meets the needle position.
9. If the hook is under the eye of the needle, loosen the 2 screws securing the needle bar, lower the needle bar until the eye is about 3/16" below the tip of the hook and lock down the screws.
10. If the hook is arriving too late, it needs to be rotated clockwise to intersect the needle above the eye. If it is too soon, it needs to be rotated counterclockwise (looking at it) That is a matter for another reply and is fraught with room for serious error. It could affect the warranty.

Did you get a manual with the machine? Have you called or contacted Cobra about this problem? This would be a good time to do so.

I'll try that this evening, and get back in the AM. 

 

Thanks for giving me multiple things to check out.  I'll update once I go through this list. 

 

Thanks again.

[RockyAussie]

That also would be my best guess. Getting snagged at the bottom on a large spool would be about that sort of measurement I would think. Note that the knot shows its coming up higher as it comes to the missed stitches which also indicates a varying tension somewhere. Crooked sitting cone?

[RoosterShooter]

On 4/3/2020 at 4:59 PM, Wizcrafts said:

Have you tried a new needle? Is the needle inserted all the way up in its mount? It it aligned with the rib on the left and scarf on the right?

Do you have sufficient foot pressure to completely hold down the leather as the needle ascends? Lifting leather causes skipped stitches.

Timing  problem

The hook timing may have moved from thread drag, or the needle bar may have raised up due to impacts and loosened screws.

Power off before proceeding

1. Remove the top thread beyond the wax pot or top post.
2. Unscrew and remove the faceplate and set it aside.
3. Remove the bobbin and shuttle cover plate.
4. Set the stitch lever to the zero forward/backward motion position (rotate the hand wheel until it becomes zero feed).
5. Use the hand wheel to move the needle all the way down to BDC.
6. Continue wheeling slowly until the needle raises between 1/8 and 3/16 of an inch.
7. Shine a light inside and see if the tip of the hook intersects the center of the needle above the top of the eye, inside the scarf area.
8. If the hook and needle aren't intersecting above the eye at this point, determine if the needle is too high for the hook when the hook meets the needle position.
9. If the hook is under the eye of the needle, loosen the 2 screws securing the needle bar, lower the needle bar until the eye is about 3/16" below the tip of the hook and lock down the screws.
10. If the hook is arriving too late, it needs to be rotated clockwise to intersect the needle above the eye. If it is too soon, it needs to be rotated counterclockwise (looking at it) That is a matter for another reply and is fraught with room for serious error. It could affect the warranty.

Did you get a manual with the machine? Have you called or contacted Cobra about this problem? This would be a good time to do so.

 

 

OK. I followed Al Bane's video online about checking the timing, and the machine is timed correctly. 

 

Now, for some unknown reason the machine is 'knocking' inside the Lower arm of the machine when I sew! 

 

This is getting frustrating.  I don't recall having these issues with my Cowboy 3200 "Out of the Box".  I'm getting to my wits end here.  

 

Edited April 5, 2020 by RoosterShooter

[RockyAussie]

Check that the screw that gets undone first when adjusting the bobbin tension has not worked its way out and hitting the race occasionally. Check there is no threads stuck down in the race. If they are not the problem..... to quote a very wise Wizcrafts...

2 hours ago, RoosterShooter said:

Did you get a manual with the machine? Have you called or contacted Cobra about this problem? This would be a good time to do so.

 

[Bert51]

If  I was to look for a noise in a machine, I would take off the drive belt and slowly turn it by hand until I find the noise, then I would start looking for where it is coming from.

It could be like Brian said, a screw worked loose or a piece of lost thread that's found a new home or even the hook hitting the needle.

But take your time and work your way through Wizcrafts list.

Bert.

Edited April 6, 2020 by Bert51
spelling

[Wizcrafts]

3 hours ago, RoosterShooter said:

Now, for some unknown reason the machine is 'knocking' inside the Lower arm of the machine when I sew! 

Did this happen on its own, without any new user action, or as a consequence of another adjustment? If an adjustment, what was it?

[RoosterShooter]

15 hours ago, Wizcrafts said:

Did this happen on its own, without any new user action, or as a consequence of another adjustment? If an adjustment, what was it?

This happened on it's own.

I was sewing 2 pieces of leather, back to back, on a 20" run, made the turn, and was heading back the other way when it started knocking really loudly.  I can feel the vibration in my foot on the pedal.

 

I spoke to Springfield Leather this morning, and they can't figure out what's going on with it either.  This particular machine has less than 2 hours on it at this time, and we're beginning to wonder if I didn't get a lemon. 

 

If I had more hours on the machine, I would think something was out of adjustment from use, but this is a brand new machine that I just recently switched to after selling my cowboy.

 

 

Edited April 6, 2020 by RoosterShooter

[Northmount]

Sounds like a screw has loosened up.

Tom

 

[RoosterShooter]

22 minutes ago, Northmount said:

Sounds like a screw has loosened up.

Tom

 

I checked all of the screws with Springfield this morning on the phone.  It's not a loose screw.  I'm sending it back to them.

[Kcstott]

On 4/6/2020 at 9:48 AM, RoosterShooter said:

I checked all of the screws with Springfield this morning on the phone.  It's not a loose screw.  I'm sending it back to them.

You were advised to call Cobra. As in the Leather machine co. In Ontario California. 
talk to Steve they will ask questions and walk you through the problem over the phone. 

Edited April 8, 2020 by Kcstott

[RoosterShooter]

On 4/7/2020 at 7:25 PM, Kcstott said:

You were advised to call Cobra. As in the Leather machine co. In Ontario California. 
talk to Steve they will ask questions and walk you through the problem over the phone. 

I had already spoken to them, and they couldn't figure it out! 

 

I have a new machine now.  Hopefully it's dialed in. 

Edited April 15, 2020 by RoosterShooter