# Thread and bobbin tension - offset to 1 side



## kalkake65 (Feb 2, 2019)

Just bought a new to us tajima tehx-c1501. Got some new needles, thread and getting it all setup. We are new to embroidery, so bare with us.

Using the tension gauge upper tension is 120-130 using polyneon 40. When running the maderia tension test the back bobbin is offset to one side. I think if it was centered the tension looks good, but open to opinions from experienced users. 

Thanks 
Jason


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## kalkake65 (Feb 2, 2019)

Added Photo


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## binki (Jul 16, 2006)

Hook timing maybe.


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## kalkake65 (Feb 2, 2019)

That's what I am thinking... I am going to call Hirsch tomorrow to see what they say and verify the correct timing for this model.


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## ElitePromo (Aug 21, 2018)

Might look into positioning finger on hook/bobbin. It should be set so that the pigtail on top of the bobbin is straight up and level. If not, loosen the screw(s) on the finger and adjust. Re-tighten and run your tension test again. "HOX" test is a little more accurate for tension. It moves the frame in every direction (side to side, top to bottom, and diagonal). Hope this helps


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## Muldo (Oct 18, 2017)

I wouldn't spend too much time chasing this down, I'd run it as is...but considering it's consistent across the colors I'd suggest hook timing is just a touch out. Not much...just enough to move the interaction.

It's also possible your needles aren't exactly straight. They need to be installed with the eye perfectly straight front/back. However, since the offest looks consistent across colors I'd say it's tough for you to have them all off a degree or two equally.


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## kalkake65 (Feb 2, 2019)

Thanks for the replys


I did check the locating bar and it is straight up and down. I did, to test move it all the way to the left and ran a test and again all the way to the right, no change in the bobbin location on the back.

I then played with bobbin and upper tensions tightening, loosening etc etc... Again no change. 

Needles are loaded straight in as far as I can see... I did try and rotate to the right. No change left gave me thread breaks. 


Going to call the tech again tomorrow... But any other suggestions?


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## kalkake65 (Feb 2, 2019)

Little update.

Hirsch tech said to make sure the locating bar on the front of the hook was centered. I verified tonight it is centered. Just to test I pushed it all the way to the left and ran a test, then again to the right to run a test. There is no change to the bobbin placement.

I then played with bobbin and upper tensions. Tighten loosen etc etc. Again no change. 

Going to call the tech back again tomorrow and get timing specs and procedure. Looks like this one is set at 197 deg. I will see if that is in spec or not. 

Any other suggestions?


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## LTPEMB (Jul 10, 2015)

Muldo said:


> I wouldn't spend too much time chasing this down, I'd run it as is...but considering it's consistent across the colors I'd suggest hook timing is just a touch out. Not much...just enough to move the interaction.
> 
> It's also possible your needles aren't exactly straight. They need to be installed with the eye perfectly straight front/back. However, since the offest looks consistent across colors I'd say it's tough for you to have them all off a degree or two equally.



You are correct its timing. I had commented on this on another forum but Its important enough to copy and paste over. leaving it alone you might be able to have it run okay but more often than not it causes way more confusing issues down the line. bobbin show on thinner satin, loops on top stitch, incomplete stitches when sewing in a specific direction. you end up chasing all sorts of answers when its simply "adjust the hook"

Text from other forum:
"Actually if you get strait even but offset lines like that more often then not when you go to do smaller details/text you end up having bobbin show on top.

I have run into and solved for this problem before. Usually its a timing issue of being too Early for optimal loop off the needle catching. 

The loop that is formed between the needle down position and the hook point position has an optimal catch point where the forces/physics involved creates the least amount of instantaneous tension on the top thread. 
Generally its when the loop is fully formed at its largest before the needle starts pulling the thread loop back out/up where the needle no longer manipulating the thread. 
That is when you want the hook to make contact with the thread as it hands off the point of tension from the needle to the hook. 

If the hook makes contact early you get a weird jolt in the top tension that pulls a small bit of excess thread gets pulled into the material. Because the release time of the rotary hook and the timing of the thread take up happen at the same time as pantograph movement you get directionally biased stitch tensions because the release always happens on the left side of the of a counter clock-ways rotating rotary hook, you end up with a looser top tension going one way because the slack in the thread tension you get a looser side, and a tighter tension going the otherway because instead of the take up lever being what pulls and forms the bottom stitch the pantograph movement is what forms the bottom stitch after the take up lever has fully pulled up the remaining slack... (Thats what I think happens at least I need an ultra high speed camera to confirm the hypothosis) 
But in practice changing the rotary hook timing solves the issue (and allows you to lower tensions to reduce puckering issues.) 

Whenever I buy up a used machine I always go through lots of testing and adjustments and fine tune the machine far beyond the original from the factory adjustments or even what a technician would adjust for."


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