friquant

Once you get your allen wrench in the screw circled in red, rock it both ways. That is, attempt clockwise, then attempt counterclockwise, then clockwise, then counterclockwise. Make sure you have the correct sized allen wrench. Also make sure you are NOT using the ball end of the allen wrench (if your wrenches have that), as the ball end only provides a small contact patch.

Do you have anything stronger? Are you saying it's a hex type, like allen wrench? Is there a lock screw holding it in place, by any chance? Can you send a photo?

I would love to have a cowboy cb3200, but it's too big to work gracefully on thinner projects like wallets. From the specs page it says the needle system is 7x3 or 794. These are very long needles, and you cannot buy thin needles in this system that have a leather point. Furthermore, when you run a thin needle with that length, they are prone to bending. Note @Wizcrafts does suggest the cb3200 in his blog on dumbing down a 441. But in general, for stitching thin to medium materials (1/8" to 1/2" total) I recommend getting a machine that takes the most common needle size, 135x16. Only in part because the needles are easy to come by in different sizes and tip shapes, but largely because the 135x16 is short enough that it does not bend easily like the system 190 or especially the system 7x3 / 7x4 / 794. Here is a photo to show the two needle systems. On top is a system 7x3, size 180Nm. On bottom is a system 135x17, size 135Nm. By the way: 135x16 is the leather-point version of the 135x17 7x4 aka 794 is the leather-point version of the 7x3

A couple drops of diesel fuel, left to sit a couple hours. That's what I use. And make sure you have a screwdriver that is a good fit for the screw. I've been using this "sewing machine" set made by Chapman. It comes with several different sized hollow-ground (paralled-sided) bits and a mini ratchet to give extra torque. Here's the amazon link where I purchased for $55.

Which direction is your bobbin inserted? Here is a screenshot of the pfaff 335 manual showing the correct orientation. If inserted the opposite direction, the thread can slide out of the bobbin tensioner, which is bad.

Does it jump to the middle when going in reverse? After it jumps to the middle, does it ever revert to its former position? When the lower thread is in the middle, does it interfere with the top thread clearing the bobbin case latch?

Are you having trouble getting the machine to stitch properly, or are you asking about the fundamentals of how a sewing machine forms stitches? If the former, I suggest making a close-up video with the bobbin cover removed, while you turn the hand wheel VERY slowly and smoothly. Here is a great example of such a video:

I would look at cylinder arm machines. The cylinder arm gives the versatility to sew 3-dimensional shapes, including the gussets on purses and bags. We're talking machines like the Juki 246, Juki (1)341, the Pfaff 335, or one of several clones of any of these machines. In terms of needle systems, I would target a machine that uses the most common needle system, which is 135x16.

I was wrong about this. I didn't realize that the 211G does not actually have a stock handwheel screw. I assume that piece with the triangle is actually the arm shaft.

What are the remaining questions on this topic? Have you made progress? Are you still waiting on a part before proceeding?

You'll need to decide what thread size you want, and then get needles big enough for the thread and material. See AlZilla's links:

I haven't found many parts on a sewing machine that bend. That is, most parts on my sewing machines seem to be a very hard material that is likely to have fracture as its failure mechanism, not plastic deformation.

An internet search for juki 243 parts manual led to this: https://www.jukisewingmachines.co.uk/pub/media/productfileupload/j/u/juki_tnu243_parts_book.pdf On pages 11 and 12 shows the hook driving shaft (part #10), the left end of which is the shuttle driver.

Maybe 3D print