Help Seamsters! Why???

[Ramblinrev]

its the tension is too loose

If that's all that is going on it would react the same whether sewing fast or slow. That's certainly a part of it but not the whole problem.

[hppyfngy]

Well I haven't made any revelations but I did get a notion from Knotty, who has the same machine I think.

He has had some similar problems when sewing very thin material like the 1.1 I'm using now and thought the problem seemed to be as if the fabric were getting pushed into the throat.

This is consistent with what I'm observing as well. If a stitch doesn't penetrate the fabric for whatever reason; slack or slippery material, dogs not holding, dull needle, I think you would get the result I'm getting. A buildup of bobbin thread below the throat. If I provide extra tension to the fabric as it exits the dogs, you can see that I am not allowing the fabric to go slack.

I don't think it's tension of the thread. I think I've checked that and just seeing the stitches makes me believe it's fine.

I have more testing to do but at the moment I'm just thinking this Brother just doesn't grip the fabric effectively enough to move this thin slippery stuff through the dogs at a high rate of speed.

Why that is, I'm not sure.

HFG

[DemostiX]

What you've written is entirely plausible: You don't get, except maybe if you know how to tweak, all the performance from a basic lightweight machine that you might expect of one that was built of cast iron and was expected to hold tolerances running full throttle. (And even then might have problems with fabric as slippery as sil.) Those feed dogs are not only doing a lot of work, the grab, pull, and release all have to just right.

On a sewing forum, a buyer of ancient iron expressed surprise that her new (to her) machine did not include the couple or few feed-dog height settings she was used to seeing on ordinary sm's. (eg silk, normal, none (feed dogs lowered). On a really prime old Singer or Pfaff or Sears, she just got all or nothing. It occurred to me that in-between settings were no doubt nice to have, but tens of millions of sms had been built for a hundred years without that marketable feature, with sewists expected to acquire skill in matching presser-foot tension to job requirements instead. Or the orbital action of the feed dogs built-in was such that skill of that kind wasn't so much required.

So, the thrill of letting 'er rip at full speed may have to be deferred until you are working with different fabric.

Or, a different type of needle may let you sew faster, which would be important in a production environment. Maybe, for example a sharper microtech needle from Schmetz would work better at high speed than the more parabolic-pointed "universal" needle that dominates the market. http://www.schmetzneedles.com/learni...dle-primer.htm. Here (or elsewhere) there are sewists who can't abide universal needles. I presume it is at speed that the compromise in that design shows up.

[hppyfngy]

Right. And there is also no way of adjusting the presser-foot pressure. It's automatic.

This is a very smart machine, and I'm not going to complain about it. I think I've just found a limitation.

I don't need to hurry, in fact I don't believe in it. But I do like things to work as they should. Maybe this is just how this sm works.

Thanks all, it's been a learning experience. I'll report back if I discover any new information.

Cheers,
HFG

[Ramblinrev]

See if you can find a "straight stitch" throat plate for that machine either from a dealer or after market. It has a small single hole in the plate which makes it much harder for the fabric to push down in.

Now to throw in a wrinkle... many of those older machines were able to sew china silk which is every bit as sheer and lightweight as 1.1 nylon if not more so. Check you needle to see if you are using "ballpoint" instead of universal or sharps. If possible, use only sharps for those very lightweight fabrics.

[gargoyle]

I did this once when I had a similar prob..
Stick a small piece (2"x2" approx.) of blue painters tape under the foot on the plate. Spin the machine a few times to pre-punch the hole. The tape will support the fabric (at least it did my experience) and it still allowed the stitch to travel thru. Trim the tape so the dogs are clear.
And the tape increases the foot pressure, so to speak, by decreasing the gap some.

I know you cleaned it once before, but check for some debri under the stitch plate where the dogs travel. Some fluff can make it hard for the dogs to travel properly.

[Pag]

I was guessing at fabric deflection and that's why I asked to set needle all the way to the right (putting the needle close to the needle hole edge on the throat plate). Sometimes having the fabric supported by 3/4 of the sides makes the difference.

[SnrMoment]

Lurk'n & learn'n. Appreciate the info provided as I make a few things with my "new" 1967 Emdeco machine. My collection of needles seems to have been growing as has my thread inventory.

[hppyfngy]

I was guessing at fabric deflection and that's why I asked to set needle all the way to the right (putting the needle close to the needle hole edge on the throat plate). Sometimes having the fabric supported by 3/4 of the sides makes the difference.

I was sewing with the needle all the way to the left, providing the support you describe. I feel certain after some more experiments with other fabric, other needles and several cleanings that this is a limitation of this machine. You just can't haul a$$ with it, especially with very slippery thin fabric.

I'm resigned to live with that.

[DemostiX]

I was sewing with the needle all the way to the left, providing the support you describe. I feel certain after some more experiments with other fabric, other needles and several cleanings that this is a limitation of this machine. You just can't haul a$$ with it, especially with very slippery thin fabric.

I'm resigned to live with that.

Same topic just came up in one of the yahoo sewing groups. Besides the tape afixed to the zig-zag plate, one of the commenting sewists said that he / she sometimes affixed slippery tape to the underside of the presser foot. It's up to you, of course to carefully cut and trim the smallest holes in the tapes for the needle.

Necchi used to think this could matter with silk. A straight stitch model with a rotateable circular faceplate includes two straight-stitch holes, one of them smaller than the other to minimize fabric deflection by the needle.

On needle position (left, right, or center): Left may be different from right in performance on some sms that don't have the bobbin case and hook move left and right with the needle.