Stitching issues on a 3200 with 5-6 oz veg tan

[BDAZ]

One of my product lines, a pouch, uses 5-6oz drum dyed leather. I use either 138 bonded nylon with a 23 needle or 207 with a 24. (Pictures are 207/24)

I purchased a spool of white bonded nylon for this job as all my tread inventory is either black or natural. 

I get perfect stitches when stitching two 5-6 oz pieces but when I reach the flap I end up with knots on the top or if I loosen the top tension the knots move below the surface but the thread appears to bunch on the down stroke and the needle punches through the tread as shown in the pics. Both look like crap!

Any suggestions will be most welcome! I am backed up and I need to solve this issue, whether by changing thread/needles or adjusting the tension or possibly working with the catch spring ASAP.

Thanks!

Bob

[SolarLeatherMachines]

it would help to see pictures of the actual product and views of the stitching about 8" away from the surface. 

[BDAZ]

[Gymnast]

I am not that expierienced here. But I like you to check the operation of your check spring. For my machine - if the check spring is not operating, the top thread may not be tight when the needle hit the fabric.

[Wizcrafts]

I would agree that the likely culprit is your check spring. The spring must hold the top thread taut until the needle pierces the material. If it lets go before that the tip of the needle will pierce the thread.

[BDAZ]

Thanks both for your help!  I have been working on the check spring tension and position of the stop. Bobby from Toledo suggested to move the stop so the hole in the spring is even with the post on the lower tension. Didn't seem to help.This is what happens during a stitch when tension is low enough to move the knot below the surface of a single layer of 5-6 oz.

 

Bob

Edited July 19, 2019 by BDAZ

[BDAZ]

I watched Alexanders video on removing and resetting the check spring. I did pull it apart and all seems normal did make sure the neck of the check spring was engaged in the hook of the check spring tension spring but it made absolutely no difference. I checking Ryan's video of threading the 3200, he demonstrates the action of the check spring but on my setup, upper tension is not enough to move the check spring at all.

 

Bob

[Gymnast]

I did also look at the youtube video

https://youtu.be/MHQBvaNkcRM

I think the upper tension should be high enough to move the check spring at any time. So to me it means the upper thread tension is too low. Perhaps the lower thread tension is too low as well. Do you have any Means of measuring the thread tension?

The Picture you have above, is that from before or after the stop on the check spring was changed? I would like the stop be lower than on the Picture to make Space for more movement of the check spring.

[BDAZ]

I did move the check spring stop back to the middle position and vertical and now the thread runs straight across from the post through the opening in the check spring but it made absolutely no difference. The current tension is the maximum tension I can use and not present knots on the top. The bobbin is set to almost maximum.

[Gymnast]

When I look at your Picture AND the video I refered to above, it seems to me that the thread is not put between the tension discs of the tensioner. I take that from the direction of the thread from the pretensioner. The thread rides on the top. It should be pulled in between these discs.