When to stop and turn the material

[brmax]

Kinda splitting hairs here but I think when the hook is a hair past tdc and enough to retain any available slack in the loop its ok.

A or one reason is the needle is not pulling a lot of tension as going up but maybe another parts function in time " wow" I'm done.

Have a good Friday everybody

Floyd

 

[CowboyBob]

The best time & to be sure you don't get a skipped stitch is to stop & turn after the thread is caught on the hook ,so this is on the upstroke (approx. 1/4")

[gottaknow]

Ok. You guys are over complicating this issue. On machines with needle positioning, the needle should stop down after the hook has picked up the loop. If your check spring is set correctly, it will take care of any slight variations in needle thread slack while making the turn. Wiz is always stressing how important the check spring travel and tension are. The heavier the leather and thread, the more important. When sewing commences, your next subsequent loop will be formed no matter how much twisting and repositioning of the work while turning. It also important not to move the handwheel during the turning process. On machines without needle positioning, turn the needle all the way down and then up far enough to accomplish loop formation and the hook picking up the loop. I train operators to note the position of the take up lever rather than the position of the needle since it's easier to visually see it. Horizontal and vertical hook orientation makes no difference.

Regards, Eric

 

[Uwe]

I made a video some time ago that shows the underside of a loop-pickup on a vertical axis hook machine. It may help visualize what's going on down there.

 

[graywolf]

Very nice Uwe, it also show why SPM are 1/2 of RPM, which seems to confuse some folks.

[graywolf]

3 hours ago, gottaknow said:

Ok. You guys are over complicating this issue. On machines with needle positioning, the needle should stop down after the hook has picked up the loop. If your check spring is set correctly, it will take care of any slight variations in needle thread slack while making the turn. Wiz is always stressing how important the check spring travel and tension are. The heavier the leather and thread, the more important. When sewing commences, your next subsequent loop will be formed no matter how much twisting and repositioning of the work while turning. It also important not to move the handwheel during the turning process. On machines without needle positioning, turn the needle all the way down and then up far enough to accomplish loop formation and the hook picking up the loop. I train operators to note the position of the take up lever rather than the position of the needle since it's easier to visually see it. Horizontal and vertical hook orientation makes no difference.

Regards, Eric

 

I am going to have to give way to Eric's experience, since he has worked on, maybe, a million more sewing machines than I have. That said, I think I will stick to what works for me in my own sewing

[gottaknow]

2 minutes ago, graywolf said:

I am going to have to give way to Eric's experience, since he has worked on, maybe, a million more sewing machines than I have. That said, I think I will stick to what works for me in my own sewing

There's only one thing I know to be fact in sewing, and that is there are no absolutes, but lots of grey areas. I do tend to paint with a very broad brush when I describe things on the forum here. The reason is because I've been head mechanic in factories with 350 operators where I had 4 mechanics working for me and I had to keep them all on the same page. Because factories sew at high speed, things have to be set very precise. I've seen machines in upholstery shops set so poorly I was amazed they worked. My adjustment techniques and troubleshooting methods are time tested for the masses. I know that if all my machines are set to position after the loop has been picked up. I have less problems. If I were perfect, and my machines were perfect, I wouldn't have a job. There are so many variables with industrial machines, I change opinions on things all the time. About the time I think I have something figured out, it proves me wrong. I've been a mechanic for 36 years and there are days in a factory I feel like it's my first day. I am always in learning mode and have learned a ton here on the forum. Back in the days of big factories, I would adjust/repair about 75 machines a day. No wonder I have grey hair.

Regards, Eric

[dikman]

You still have hair? So it sounds like the optimum time to turn material is just before the needle exits on the upstroke? (But while the needle is still below the needle plate so that the needle is still supported and won't bend/break). That will ensure that the loop has formed, I guess. Looks like I'll have to experiment with my machine to see what it's happiest with.

 

Thanks for starting this, Uwe, lots of good info has come out of it.

[dikman]

I did some experimenting, using the Singer 166 with #69 and #138 thread, and stopping at the bottom of the stroke, part-way down and with the needle just through the leather. All worked fine with no dropped stitches. So, feeling confidant, I stitched a dress belt that I promised a club member (I'd been putting it off due to dropped stitches on the last one I did for him). Got a dropped stitch at the turning point on the belt tongue () and some thread got caught up at another turning point on the pattern ().

AAAAARRRRGGGGHHHHHH!!!!!!

[Uwe]

So that's what it was - I thought I had felt a disturbance in the Force.

Edited June 25, 2016 by Uwe