Help! Presser foot not moving, needle foot going wrong direction, Techsew 4100

[RockyAussie]

5 hours ago, YinTx said:

I did have to do some more timing adjustments after all that, and in general it will catch the thread on backstitching now.  It does still miss occasionally, maybe something I am doing wrong as an operator?  I am using a 794 needle, size 23, with a 207 thread in this latest run.  Brand new, just got the package this week in the mail.  The other needle as far as I know was new, but was a size 25 and if I recall correctly, was using a 277 thread.

 

I did not see the back plates opening at all when stitching heavy leather.  I'll see what happens when I lift it with my thumbs next time I'm working with it.  Currently, the presser foot does not raise very much, if I adjust the feet to allow this, it results in binding.  I still have to take the presser foot spring and grind it flat, we'll see how that goes.  Meanwhile, I did manage to successfully stitch this bible cover with it!

YinTx

Good looking job @YinTx Happy to see you have it nearly all working now.

[YinTx]

So, I left the large needle in there, and stepped the thread down to 138 top 90 bottom.  Stitched the next bible cover, and lo, knots akimbo.  Thread path is fine, coming off the spool fine, nothing that should have been interfering with the tension that I could find, but there it is.  Every other stitch the knot is on the bottom.  And aren't these ginormous holes for the thread?

What am I doing wrong this time, lol?

 

 

[kgg]

7 minutes ago, YinTx said:

What am I doing wrong this time, lol?

What I would try in a small sample is backing off the bottom thread tension slightly first then if that didn't work increase the top thread tension slightly. I still think the #23 needle maybe creating a too small of a hole in the that particular leather. There might also be some thread related issues like thread consistency, size of thread spool (8oz vs 16 oz), brand name thread versus cheap china stuff, thread type (bonded nylon vs bonded nylon). The reason I mention thread is I am also seeing thread strand twisting and separation on some of the stitches. Which maybe a result of the distance from the top of the thread spool to the first guide in the thread spool stand being to small as it needs to be 2.5 times the height of the thread spool to help remove twisting of the thread or thread backlash or a bad spool of thread.

kgg

[RockyAussie]

14 hours ago, YinTx said:

So, I left the large needle in there, and stepped the thread down to 138 top 90 bottom.

It looks to me like you have used the 25 needle with that 138/90 thread mix.(Bad choice) Particularly in firmer veg type leather when you use an oversize hole you give the knots very little resistance to set in a predictable way. I would recommend using the 23 needle with 138 top and bottom as a starting point. If there is still inconsistencies then check that the bobbin shaft has no threads or burs that stop the thread pulling out smoothly. After that pull the top thread down by hand and watch the primary tension plates for even movement. There should be a couple of felt washers in there on either side of the centre piece and some times it can help to dissemble them and check for any catching burs and the like then give them a few drops of oil before reassembling them.