Horrible topstitching - Mayday

[toileandtrouble]

Trying to shorten a pair of trousers.  Well, they are shortened, but the topstitch is impossible. It seems to be a sort of cotton canvas with elastane.  I have top stitch thread in the size 16 topstitch needle and ordinary thread in the bobbin. I am using a Pfaff QE4.0 and it has jammed and broken one needle.  Now it stalls after one stitch and says the motor is overloaded.
Is there a magic needle/ trick/spell to make this go right?  Can anyone help?

[arrow]

I always max out on needle size for top stitch thread and go for #18 right away. I even keep #19 and a few #22 in my drawer. Upping the size works; sturdier and more rigid needle prevents it from bending and hitting the throat plate. The larger groove along the side helps the thread passing through too. Too small needles can give tension problems; like you never get enough uppper tension.  Some machine don't behave well with extra strength or top stitch thread  weights what ever you do, especially if the bobbin tension isnt easily adjusted. A Pfaff QE. 4 should in theory be capable enough though. Do you have another machine for back-up?

[StitchinTime]

If you are struggling with top stitch thread, using two strands of normal thread sometimes looks OK.

Wind some thread onto a spare bobbin and rethread the machine using the strands from the reel and spare bobbin as one. It is worthwhile sticking with the larger needle as it makes threading it with the two strands much easier.

[arrow]

Second thought; trouser fabric these days isn't very heavy, especially with extra stretch they tend to be rather light weight. Sewing over a double felled seam can be challenging, but the rest should be easy work. Have you checked for thread or something caught the bobbin - feed dog area? Maybe the thread are caught or looped in the threading path some where.

If it's the top stitch thread weight acting up, keep a second machine for heavier theads and fabrics. If the machine stitches the seam with regular sew-all weight thread and doesn't complain, I would assume it's the thread.

[toileandtrouble]

Thanks folks, will try for an 18, might just be one lurking somewhere.  No bits of thread around, it works beautifully on everything else.  This fabric is extremely closewoven.
Well, no 18s, but got some on order now.

[Morgan]

If the fabric has elastane try a size 14 or 16 Stretch Needle.
Hand crank over thicker layers.

[arrow]

Could be worth trying a stretch needle, but I think Gütermann recommends size #16-#19 (I looked it up) for top stitch thread weights. As mentioned it is the combination of densely woven fabrics and top stitch thread that call for max size needle. I have sewn in woven and jersey with elastane and spandex, but I can hardly notice any difference between stretch, microtex and sharp point. The only time microtext turned out to be better was for a very flimsy jersey where the stitching tore the fabric with a regular needle. I guess there might be differences between machines too.

[toileandtrouble]

 I couldn't get the Pfaff to go through with the hand wheel and decided I couldn't wait for the needles to  be delivered, so dug out the lovely old Bernina and the special jeans foot I bought for it. The Bernina galloped through with the 16 needle. (And I'd forgotten how lovely and quiet it is)
 I can really recommend that foot, it doesn't baulk at the thick seams on the hems.   

[arrow]

Most machines should do it, the old Berninas are tough enough. It might be safe guards in the most fancy computerised machines, to prevent overload. Hemming jeans is what a basic machine must handle though.  I am a bit surprised at the Pfaff 4.0 haulting at three layers of basic trouser material? If it's one of the old mechanical Berninas, give all the oil points a drop or two and run the machine a bit, under the top of the freearm too.

[toileandtrouble]

Most of the hem is 3 layers, at the seams it is 6.  The real problem was the material, I think. 

[arrow]

You are probably right, I have had machines act up with densely woven duck, a bit rough and thick, twill weave canvas, corduroy. Scuba (the diving stuff) is like stitching trough eraser rubber. Some machines just keep on stitching through most work. The double felled seams are 4x3 layers in a hem, many will tweak their machines to stitch through the mumpy seams.

[dolcevita]

I recently made a shirt for OH from Liberty tana lawn and although fine, it's incredibly close woven.  I also use a Pfaff QE 4.0 and found that a microtex needle went through the layers quite well.  It wasn't so much about the thickness and strength of the needle as the sharpness of the point.