coats 207 top and bottom in my Juki 441`

[esantoro]

I mostly use coats 207 top and bottom in my Juki 441` clone without any problems. I'd like to starting to experiment with using 277 in the top and 207 in the bottom with a 25 needle . The thread seems to be fraying and the stitches do not look as neat as with a 24 needle and 207 coats poly top and bottom.

At first I thought the tension, both top and bottom, were too tight. I experimented with several adjustments and am sure that I've got good tension settings. I've also used a new Organ diamond point needle (#25). No change. Now I'm wondering if I should go up to #26 needle. Does this sound right for 277 thread top and bottom. All my references tell me a #25 is sufficient.

I also lengthened the stitch per inch setting, one click longer than setting 4. That seemed to help a bit. I am stitching on two layers of 5/6 oz chrome tan, and realize maybe this leather is too thin for 277 top thread, but I still don't see why the thread should be fraying.

I'm also thinking that maybe I need to use a lube pot with 277 thread. I'll try thicker leather and an even longer stitch per inch setting.

Thanks for any help you can offer.

Ed

[esantoro]

Well.,.. I've been playing around a bit. I can get nice stitches on four layers of 5/6 chrome tan (and probably three layers, too). Does this mean that it will be impossible to use 277 poly on two layers 0f 5/6 chrome tan, or must I simply fiddle around more with tension adjustments?

It still doesn't make much sense to me why thread was fraying on two layers of 5/6 but not on four layers. If thread is fraying and appropriately sized needle is new, is the reason for the fraying always top tension being too tight (as compensation for bobbin tension also being too tight)?

Has anyone here ever used 277 on two layers of 5/6 oz?

Ed

[Art]

Hi Ed,

You'd have to have the tension pretty darned tight. Fraying:

Needle or thread path has a burr on it make sure hook is smooth,

Bobbin tension too high causing overcompensation on top tension,

Machine not threaded properly,

Secondary tension set too tight (there should be minimal or no tension here),

Needle too small (for 277 a 200/230 25/26 should work).

There are other things, but they would give you trouble all the time not sporadically.

Chrome tan is different than veg, veg is stiffer and self stabilizing whereas chrome tan is less stable and will tend to move around when it is going through the machine. Gluing layers together will give more stability and especially for only two layers. More layers will have more mass and will be more stable and easier to stitch. Sometimes a more aggressive bottom feed will get the material through better, like on the 618 or 797. Chrome tan and fabrics (not webbing because that is pretty stiff) are usually problems with big stitchers, however a blanket foot with a big set of feed dogs and needle plate to match can solve much of that problem. I use that setup on the 4000P to do custom elevator blankets. Most chrome tan (within thickness limitations) I sew on the 618.

Art

Well.,.. I've been playing around a bit. I can get nice stitches on four layers of 5/6 chrome tan (and probably three layers, too). Does this mean that it will be impossible to use 277 poly on two layers 0f 5/6 chrome tan, or must I simply fiddle around more with tension adjustments?

It still doesn't make much sense to me why thread was fraying on two layers of 5/6 but not on four layers. If thread is fraying and appropriately sized needle is new, is the reason for the fraying always top tension being too tight (as compensation for bobbin tension also being too tight)?

Has anyone here ever used 277 on two layers of 5/6 oz?

Ed

[esantoro]

When going from 207 thread to 277 is it normal to tend to back off quite a bit on both top and lower tension, as the larger thread is already going to provide more tension of its own, more friction throughout the thread path and through the leather? I'll play around a bit more. One thing I have noticed is that with my shuttle hook, if I back off on the bobbin tension too much, the flang of the bobbin tension spring stands up too much and catches the top thread when it comes around the bobbin case.

Art, your tips are very helpful. I now need to try a 26 needle and back way off on the secondary tension.

Thanks for your help.

Ed

[Art]

Hi Ed,

I don't have many problems from 207 to 346 and anywhere in between; maybe a little tweak on the top tension but no more than a turn. The secondary tension is the one on the head cover at the bottom of the head and that doesn't need much tension if any, a couple of wraps around it with the thread is all I have ever needed. You do need some tension in the bobbin but it should not be more than a pound or two of resistance. If anything you need less tension with chrome tan or softer leathers as they have considerable give and don't need to be pulled as tight. Tensions for Veg tan need to be a bit tighter, but not strung up like a banjo. I lube everything I sew on the big stitcher except the bobbin which I run dry. After you sew for a while, you can get the speed cranked up kinda high and even with a sharp needle the temp can get up there and maybe cause a skipped stitch, the lube keeps the needle cool and the thread doesn't stick to it. I don't think lube is your problem right now though, I just mentioned it because you did.

Art

When going from 207 thread to 277 is it normal to tend to back off quite a bit on both top and lower tension, as the larger thread is already going to provide more tension of its own, more friction throughout the thread path and through the leather? I'll play around a bit more. One thing I have noticed is that with my shuttle hook, if I back off on the bobbin tension too much, the flang of the bobbin tension spring stands up too much and catches the top thread when it comes around the bobbin case.

Art, your tips are very helpful. I now need to try a 26 needle and back way off on the secondary tension.

Thanks for your help.

Ed

[esantoro]

For the longest time I had thought that the tension discs closest to the lube pot were the primary tension adjuster, the one that must be adjusted most frequently. I understood the tension wheel (not discs but the wheel that turns) where the thread wraps around 1.5 times before going through the take-up arm and then down to the needle was the secondary tension adjuster, which didn't require frequent adjustments.

With the above understanding, I was experiencing difficulties getting the correct tension. Then I had either read something or talked to someone and was made to realize that my understanding above had everything reversed, that the the primary tension adjuster is the tension "wheel" closest to the needle, and that this wheel is the tension adjuster that should be adjusted the most frequently. This understanding had been serving me well with 207 to 138 thread.

Art, from your last reply, I'm beginning to think that my original understanding is the correct one. I'll revert back to that original understanding and see how things work out.

Thanks,

Ed

[esantoro]

aha, I found the culprit.

Here is a page from the Toro 4000 manual that must have been the thing that informed me to view the bottom tension wheel as the primary/main tension adjuster and the top "discs" as the secondary/auxiliary adjuster.

Ed

toro4000tension.pdf

toro4000tension.pdf

[Art]

Ed,

The one up near the lube pot is the one to adjust, why they call it the Aux is beyond me, I call it primary because that is the one you use the most and has the presser foot release on it, the other one I don't use a lot. Them damned Chinese manuals.

Art

aha, I found the culprit.

Here is a page from the Toro 4000 manual that must have been the thing that informed me to view the bottom tension wheel as the primary/main tension adjuster and the top "discs" as the secondary/auxiliary adjuster.

Ed

[esantoro]

I'm at wits end. I've been experimenting all day.

I backed off the tension to a point wehre I know that tension is not the problem.

I took a good look at the top thread in its travels around the shuttle hook. It seems that 277 thread is being held too tightly against the hook, which is where the thread is beginning to fray. I don't have this problem with 207 thread.

ed

[Art]

Ed,

New needle and even a size larger. Check the whole thread path for burrs and rough spots, also pull the shuttle out and check for a burr or rough spot on it. Is it fraying the top thread or the bobbin?

Art