Thread Tensions On Multiple Machines

[piddler]

For the life of me, I can not get decent looking stitches out of the machines I have. I have read all the topics here, and even went so far as to ship my Techsew 4100 all the way back to Canada for Mike and Ron to adjust for me. When they sent it back it was great for one material and lining, but anytime I chose to sew something else with a different thread, needle, etc it would never be the same. I have good quality thread so that's not the issue, but especially black seems to be the worst. My machines are the above stated Techsew 4100, and a Bogle import like the Techsew 2700.

On the 4100, I am using a #4 braided thread on the top, and 277 in the bobbin sewing with a 7x230 chisel point needle.

And this is through 2 layers of 8-9

Lets deal with the 4100 issues, and then I'll seek y'alls help on the 2700. Thanks in advance. I am a long time leatherworker, but new to machines above a Singer class 15.

[TXAG]

Your tension will need to be adjusted any time you change thread type and/or the thickness of what you're sewing...

[piddler]

Small adjustments are fine, but not this.

I went back and oiled the machine again, and upped the needle to a 250. That seemed to help a lot, but watching the Cobra Class 4 videos they rarely make over a turn difference in tension no matter what they are sewing and that's where I need to get to with this. Thanks for the reply TXAG. Does that mean you are in Texas?

[piddler]

31 views and no other comments?

[piddler]

Ok, here is a picture of the next machine, and a few of what it continues to do to me. I've got a lot of projects to sew but cant afford to mess them up with improper sewing:

[Itch]

It sure looks to me that you do not have enough tension on the thread.I would start from the beginning and make sure that the thread is threaded through the machine properly.If you continue to have trouble I would try and find someone local to help you or to look at the machine..It is a little difficult to explain things over the internet some times..

[GerryR]

I would also check / increase the tension on the presser foot. If it is too low, then all the thread tension in the world isn't going to help, because the foot will be allowing the work to rise against the thread tension instead of allowing the thread to pull into the work. I found this to be true, especially on lighter-weight and supple leathers.

[Northmount]

Also make sure you hang onto the top and bottom thread when starting to stitch. Tension is more even on the starting stitches and prevents bird's nest under the bobbin.

Also, do test runs and reset the tension as required each time you change leather, thickness, thread and needle size. Use the same materials in the same configuration for your test/setup runs.

Tom

Edited October 13, 2013 by northmount

[Wizcrafts]

Sometimes you get a spool of black thread that has been double-dipped and it is almost like a coil spring. This thread tends to twist a lot on its way off the spool and on down the line. I have even watched springy black thread lift right out of the upper tension disks! Thread like this needs to be stabilized, even if that means feeding it through an inverted funnel sitting on top of the spool. Then, go through a hole in the top post (if exists) and around the post, then through a second hole, if one exists. Do whatever it takes to keep your thread from coiling on the way to the needle.

When knots move around a lot, up and down, something intermittent is changing the tension. Knots on top are caused by either too much top tension, too little bobbin tension, too large of a needle, or too large thread for the thickness being sewn. Knots on the bottom are caused by too little top tension, too much bobbin tension, or too small of a needle. Try to balance your top tension for a smooth pull with the foot lifted and top disks partially separated. Take the thread out of the eye of the needle. Pull out a few feet and if you feel the tension changing, look to see where it is happening. Maybe the thread is dropping under the spool or spool support. Maybe it is looping around the top guide in the thread stand? Springy thread can even twist inline and form a knot!

Next, pull out a few feet of bobbin thread and test for a consistent, even pull. If you feel a hesitation once per revolution of the bobbin, pull it out and clip the little starting thread stub off at the hole in the bobbin. A starting thread stub on the inside will tend to get caught in the anti-backlash/bobbin ejector beehive shaped spring inside the bobbin case of 441 type machines. This increases the bobbin tension at that point in rotation and lowers the knot a bit. An out-of-round bobbin can cause the same problem. Improperly wound bobbins, with loose windings, can cause the thread to unwind against the inside of the bobbin case and even pop out of the tension spring on the case. Poof, no bobbin tension!

As for needle sizes, you say you are using #277 in the bobbin, with #4 braided thread on top. I am not familiar with that thread at all. If it has the same diameter as #277, a #25 (200 metric) needle should suffice. If it has the diameter of #346 bonded nylon thread, a #26 needle should be big enough. If your needle is much larger than the diameter of the knots being formed by the top and bottom thread, vertical placement will be hard to control. It would require unchanging top and bottom tensions.

If the work is thinner than 8 ounces, move down to #207 thread, with a #24 needle. The knots will be easier to control.

One more thought: I sew a lot of different projects, some of which have areas that don't make full contact with each other all the way through, or on the bottom. The knots tend to move when one encounters these open areas. Sometimes they form under the work, other times, nearer the top. More pressure on the foot may help to compress the layers and force the bottom all the way down.

[piddler]

I will try some other thread as soon as it comes in. The thing is, white seems to always work better, and while I prefer contrast stitching some of my customers don't. I have chased down all the guidepath potential issues, thread comes off the spool cleanly, machine is clean and freshly oiled. I'm beginning to think that I have had these projects sitting around too long before sewing and the leather has dried out. (possible????) I really like the braided thread (we use it in boot making at Justin and Tony Lama) but I think I'll quit using it and just go with the 277 for holsters. No more time to experiment this weekend, but everyone please keep the suggestions coming. Thanks Wiz, you were really the one I hoped had time to respond.

[piddler]

I seem to have the issues semi worked out on the 441 clone. I've uploaded a couple more pics. Does it look to you like the needle is still too big for what I am sewing? It's 277 thread with a 200 metric needle (if I can see it well enough)

Here is where I need your advise. You know I have the big 441 and the 2700 machine. In the first pictures I posted all that was sewn with the 2700 as it was just single layers of 8-9oz with the ostrich and pig lining. Now I'm going to be sewing it all together and that requires the bigger machine. In the future should I try to set up the 441 to sew all of it, or just use the 2 different machines? I have the stitch length pretty well matched but I can tell 2 different machines sewed it. What do y'all do?

[dirtclod]

The back side looks like you have the wrong type of needle or it's really dull to me. Are you using a leather point needle ? I use a 200 needle and 277 thread on top and 207 on the bottom and don't ever remember having the backside look like that all pouched out unless a needle was really dull.

[Red Cent]

Have you tried adjusting the stitches per inch? Seems awfully long. And the pictures show really long stitches in the corner. That usually happens if you turn the corner incorrectly.

On the 441, I would suggest turning the top tension (only) disc 1/4 turn tight. At a time then test.The thread has not enough tension to overcome the bobbin thread.

I use 277 poly on top and 207 poly on bottom with a 25 needle. I have almost no tension on either disc. Light bobbin tension.

Have you read the post from Massive on how to adjust the bobbin tension?

[piddler]

Ok, the good news is I finally seem to have gotten the tensions worked out on the 4100. Here are a few pics to show it:

But now, my old nemesis of the presser foot marking the leather is back. As you can see there is no adjustment left either on the top, or the banana slide adjustment at the rear of the machine. Any suggestions?

[Wizcrafts]

Take the feet to a machinist who has an industrial buffer and have him/her buff the bottom edges of the feet.

[piddler]

Thanks so much for the reply Wiz. Am I looking to just polish the bottom of the feet, or are you suggesting I actually remove a bit of the metal? These are the feet I am using:

[zoomer56]

How thick in inches is the work in your last picture? How much lift is available for the feet? I wonder, if it can not be adjusted anymore if you could fabricate something to allow more adjustment. I bet Wiz will have an answer.

[piddler]

That is just 2 layers of 9-10oz. I can get lots of height when lifting the feet, it's just while sewing that the feet don't rise very far. I have read all the Cobra, Techsew, tutorials but cant find anything that will allow further adjustment.

[piddler]

Heres a couple things done with the 4100...

[zoomer56]

Piddler . . . have you figured out how to sew without leaving foot tracks?

[piddler]

Replaced tension spring with a lighter one, ground the bottom of the presser foot down just a hair in the corners of the bottom in front and back, and polished it all with a dremel and jewelers rouge. Its still not perfect, but wayyyy better than it was.

[Wizcrafts]

The amount of lift in the alternating feet is adjusted on the back of the head, via the sliding crank arm sticking out the back, that moves up and down inside a curved slot. Loosen the screw that locks the position and move the arm down for more lift during operation. When you get the amount of lift you want, lock the screw back down.

There is also an adjustment for the moment that the inside foot hits the throat plate. It is done via the large hex head screw on the crank on the left end of the same assembly that sets the lift. You can fine tune the lift of either foot, in relation to the other, using that crank.

Note: the moment that the inside foot makes contact with the material, relative to the needle, is important and may affect the reverse stitch length.

[piddler]

Thanks Wiz, but if you look earlier in this post we already did all that. Hopefully it will help others tho.