Issues Sewing Corners with 2750 Pro

[JoshR]

Hello, having some tension issues when seeing corners or making 90° turns. I’ve re-threaded so many times, changed the bobbin, changed needles, tried smaller thread and needles, cleaned the tension discs and bobbin area, and seemed to have done just about everything I can find online to remedy this. 
 

The tension looks great when sewing a straight line. No loops on the top or bottom and it looks like thread is meeting in the middle. The only issues happen when sewing anything other than a straight line. 
 

I’m using size #138 thread and a 136x16RTW needle size 23. 

Any ideas?

 

Edited Monday at 05:39 AM by JoshR
Forgot some info.

[JoshR]

[AlZilla]

If I recall, the size range for v138 is 19 to 22, so maybe a smaller needle.

The process for turning a corner is

• stop at the corner with the presser foot all the way down
• raise the needle about 1/4" from bottom
• raise the presser foot
• turn the workpiece
• drop the presser foot
• keep going

Actual experts will be along after they have their coffee.

[kgg]

5 hours ago, JoshR said:

No loops on the top or bottom and it looks like thread is meeting in the middle. The only issues happen when sewing anything other than a straight line. 

Just to add to @AlZilla comments.

when you stop to do a 90 degree turn:

i) bury the needle to the bottom and then raise the needle about 1/4"

ii) raise the presser foot up slight to take the tension off the material and the turn the leather.

iii) drop the presser foot back down and continue.

Some of your problems are probably being cause by not holding the threads for the first three stitches and then back stitching to your starting stitch that will lock the so the threads don't get pulled.

5 hours ago, JoshR said:

I’m using size #138 thread and a 136x16RTW needle size 23. 

I am going to assume you meant 135 x 16 needle not 136 x 16. For V138 thread the range is #22 to 24 depending on the thickness and type of leather. Veg tan I find grabs the thread more then chrome tan.  Here is a link to a good thread size vs needle size chart ( https://www.tolindsewmach.com/thread-chart.html )

Looking at your photos the leather looks very thin which means there is very little thickness to constantly bury / hide the bottom knot in. 

I would suggest:

i) you try again with either thicker leather or a few layers of thin leather to give the needed space to burying the knot.

ii) you lock the starting stitches.

kgg

[Wizcrafts]

10 hours ago, JoshR said:

The tension looks great when sewing a straight line. No loops on the top or bottom and it looks like thread is meeting in the middle. The only issues happen when sewing anything other than a straight line.

Aside from, or in addition to trying a smaller #22 needle, you can tighten both the top and bottom tensions and re-balance the knots. Tighter thread tension can sometimes offset knot placement problems caused by the machine or the leather.

[ljk]

Needle timing and tension release.  Just because it sews in a straight line doesn't mean it will turn a corner.  A little up and down on the needle may help.  Also look where in the lift cycle when the thread releases, should be near the top.  Your picture indicate that may be the problem.

[RockyAussie]

I notice that the knot mostly shows when doing a tight 90 degree corner. This means that the the needle is too large for that size thread you are running in the bobbin. Go to a 22 needle first. If it still shows up a bit then when you are about to enter the corner hole just allow the tip of the needle to just touch into the leather enough to turn it before allowing the needle to go into the leather. This will stop the hole from becoming too open when you spin it which then forces the knot to have to pull the knot into the leather the same as the other holes. You will notice at present that the knot does not come to the top so much when you turn the job when turning one way as against the other way in the corners due to the shape the needle tip gives when making the hole. Last suggestion, make sure the bobbin thread is not more than 1 size smaller than the top thread.