nejcek74

There is a screw beside the hook assembly that after untightening allows you to set relative rotation of the hook assembly and proper function of that finger.

Love the Germans 😁 so pedantic and systematic, but they still fail to be on point. In the part list of n291 tha part has name Greiferspitze, but this must be a mistake and your source is right, hook point is hook point and the counter hook point cannot have the name. Yes, I meant the throw of the check spring. Btw watching your video, your bobbin case opener/thread release finger is not moving, you need to reposition the hook a little bit. The finger in that opening should open to let the thread through and close after to make the opening on the other side. There are videos about this somewhere around but I cannot find that atm.

This is explanation from Cerliani: which follows what your experience is and what Constabulary said, that with thicker threads the full gib is not always used. On my Pfaffs I have some hook variants with short and long gib for the same machine. They are variants for either A/B and C/D thickness classes and different gib goes with different hook. Of course you can try and take this part away, but I am not sure exactly why. You wrote: "My problem is, that the thread is pulled hard by the take-up lever on this Gegenspitze before the thread finally is pulled off the end of the tip." Does it cause any real problem, like skipped stitches, broken thread or similar? Maybe you just need to make a little bit longer throw of the spring before the take-up lever? Have you compared hooks for different subclasses? Find if the differences is only in the gib or also in the other parts. This is for DA N291, gib looks always long. Durkopp also names it "Greiferspitze"

Threads used for authentic denim construction are either a cotton and polyester blend or pure cotton. You may need to use a larger needle. While the L-twist seems the most likely cause, you should also check that the distance from the hook to the left and right needles is consistent.

In trouser-making, there is a lot of chain stitching, which has all the necessary construction properties. Examples include the belt and the main seams of the trouser leg. Chain stitching is more resilient under constant stress and stretching, and unravelling is not usually a big problem. Does anyone have any experience of jeans unravelling? I haven't heard of it yet. I have a few old Union Special chain stitch machines at home and, except for one, they were all used for trouser production. The odd one is an off-the-arm machine that was used for knitted fabrics, but hopefully I will be able to adapt it for canvas. As most new machines use lock stitching, I guess there were historical mechanical and material problems with that. Perhaps also with using cotton threads, etc. Similar to awl and a needle machines, which you rarely see these days. Modern production is moving towards standardisation, so many special machines are being phased out, construction is simplified etc, everything in order to lower production costs.

it's about speed and strength. Don't forget that jeans is the grandfather of apparel mass production. Chain stitched seams are stronger and I think also faster to make. And you don't need the bobbin.

It's very much a question of garment construction. Jeans trousers and jackets can mean crossing flat felled seam with 16 layers of heavy denim. That's a lot. Classic approach was a chain stitch machine with a heavy puller. A triple feed machine works well, albeit a little bit slower. But people manage to do it also with old tailor's sewing machines, a hammer and careful construction, i.e. avoiding crossing flat felled seams. My leather garments were always kind of basic so I had less problems with them than with denim trousers.

I guess that's the one Looks kind of normal screw, you can always but another one. It's the big rocker that is holding the needle bar, this screw is used just to tighten it. The only problem with is a screw could be un-tightening during the use, that you can probably solve with Loctite. I would be careful not to damage the thread inside the rocker. That is for sure much more expensive to change.

You have skipped stiches and a nest bellow? Have you checked the timing of the machine? here is one document, check the added text at the end https://docs.uwe.net/Pfaff-145-545.pdf you can also check different pfaff 1245 Service manuals which have nice graphics. It is much newer machine but certain things are same / similar etc

As it is an old home sewing machine, do you know this forum: https://www.victoriansweatshop.com/ they have some knowledge there

I use the second pedal for reverse, but I really don't see a reason why wouldn't you use it for a foot lift. Just connect the pedal and the lifting rod either with a chain or a wire.

Great project, Beefy! I really like elevated DIY projects, and I hope you succeed. I find the needle positioner extremely useful. What are your plans for the controller — will you use an Arduino or something else that can be programmed? In my opinion, you describe the basic functions well. What I would find useful is: - the ability to check and auto-apply signals from different types of needle positioner, as you already described. - the ability to easily define the up and down positions by turning the wheel by hand and pressing a button. Currently, on my controller, I can do this either by typing numbers into the controller or by moving the three metal discs inside the positioner mechanically. I always spend too much time fiddling with that. A more advanced function would be to perform automatic backtacking ((three forwards, three backwards, three forwards, or something programmable) as you are describing, that would be great.!!!!!

most of my machines have additional small pedal for reverse as I have simple setups with cheap servos or old clutch motors without control. Reverse is anyway the sewing machine function and it is just chain/rod connecting to the reverse lever. That's number 4 on the image.

my solution for low speeds is a needle positioner, going from up to down and back up with as much time in between as you want. No problems with low speed/power ration and the needle always finish the cycle (locks). For a cheap servo is usually also a cheap needle positioner, sometimes they come included. All you need is half an hour to instal it, even if you get the instructions they are often just for something else :)))))

Aren't that those the parts?