Wizcrafts

Try listening as you handwheel the machine. It kind of sounds like gears are grinding from being too close together. I might also be the opener arm pulling the shuttle all the way back with a hard stop. There must be a little clearance when the arm pulls the tab back.

This topic, although interesting from a technical and argumentative position, has been thoroughly discussed to no end. The facts are what they are and arguing about them doesn't change them. Bobbins are required in lockstitch machines; period. If anybody has a better idea that will keep a bottom thread in play without a self-contained bobbin inside a shuttle, they should patent that technology and try to market it to the major companies that build sewing machines. We will be happy to promote your invention! Thus, as much as this has been interesting, it is pointless. I am locking the topic.

You're missing the main point of how the bobbin functions in a lockstitch machine. In order to overlock two threads to sew things together firmly, you need to cause the top thread to wrap around the source of the bottom thread. It surrounds the bobbin case/shuttle completely. This precludes having the bottom thread coming from anywhere except from a self-contained bobbin that resides inside the shuttle case. Any external thread would jam the machine as the loop goes around the shuttle. If that thread was feeding through a hole on the middle of the shuttle, the top thread would get snagged by it as it tried to work around the top and bottom of the shuttle. You see, the normal position where the bobbin/bottom thread gets pulled up is after the tension spring and under the throat plate. The top thread, having surrounded the shuttle, with its bobbin, pulls up with the captured bobbin thread in the middle of its shrinking loop. If you can get a hold of a home sewing machine you can watch how it functions to form stitches. Then you'll understand why your system fails to pass muster.

Yes, that's what I'm saying. I wish it wasn't so. If anybody was able to figure out a way to replace bobbins in a lockstitch machine with a spool of thread, they would have by now. The only workable solution to using bobbins is a chainstitch system. Redwing boot uppers are sewn on triple needle chainstitch machines that were designed in the late 1800s and early 1900s. The company that made these obsolete machines was named Puritan. They only use thread that is on top; one spool per needle. The chain is formed under the throat plate by a so-called "looper" mechanism. The top stitches are almost always perfect. The bottom stitches have loops showing where they are wrapped around the thread that got pulled under the work.

In addition to proper scarf alignment, make sure that the needle is the correct system for the machine, and is all the way up in the hole in the needle bar before being tightened in place. When aligning the sides, make sure that the eye hole is perfectly inline left and right on your machine, and that the rib side faces away from the hook, and the cutout scarf faces the hook. If the new needle is inserted correctly and the machine still won't pickup the bobbin thread, either the shuttle/hook assembly was knocked out of time, or the needle bar was force up a little, putting it out of position for the hook to catch the top thread loop. Remove any cover over the shuttle so you can watch it in action and hand wheel the machine while you watch the needle reach bottom dead center, then ascend about 3/16 inch. At this point the tip of the hook should be intersecting the thread loop that was formed when the needle ascended. If the hook has already passed by the needle, the needle bar may have been knocked out of time by the impact. Set the hook inline with the needle, loosen the screw(s) on the needle bar, then pull it down until the eye is about 1/8 inch below the tip of the hook. Lock down the screws and see if it now sews. Make sure you do this as the needle is moving up from BDC as this is when the loop is formed by the upward motion.

Wrong! When the needle, which contains just the top thread, reaches BDC, then begins to ascend, it forms a loop on the side where the hook resides. At a certain position of motion, the hook picks up the top thread, above the eye of the needle, and carries it around the bobbin case. The bobbin thread is surrounded and captured by the top thread on its way out and back up. That loop of top thread surrounds the bobbin case as the hook rotates or oscillates back and forth. As the top thread is pulled around the shuttle by its hook, at about the halfway point, the take-up lever pulls the top thread the rest of the way around the shuttle, then up into the material, forming stitches with overlocked knots of the top and bottom threads. The hook is merely a sharp point connected to the shuttle. Some shuttles are rotary and others oscillate back and forth. The top thread that was pulled off of the needle totally surrounds the shuttle on its way back out. The lockstitch process requires that the bottom thread be in a self-contained structure, not fed from an external spool. The top thread surrounding the shuttle would get snagged by an externally fed bottom thread that wasn't contained inside the shuttle. Maybe, someday, somebody will figure out a way to form lock stitches from two spools of thread, one on the top and one on the bottom, without the use of a self-contained bobbin in a shuttle. If that person obtains a patent and produces a working machine, they could become a dad gum gozillionair!

I can't see the pictures. Only Apple computers or phones will display that file format, unless the user has installed a file converter app..

@Brad denham I can't see your photos because I use a Windows computer. Can you save them as .jpg files and repost them?

Sometimes, it's the way the thread comes off the spool. SOme thread is twisty. Some is bonded too much or too little, some windings may have crossed over or under other windings, some windings fall down and get caught under the spool. I've had knots suddenly appear on top after laying perfectly in the center. Sometimes, I discover that the top thread has twisted itself around the thread stand and is jammed tight. Even the bobbin thread can jump out of its position under the tension spring. Or, it could get caught under the bobbin.

Fascinating!

Smooth bottom presser and alternating feet are standard on the Juki 1541. It is unusual to find feet with teeth on that model. serrated feet are normally used on dual feed machines that have a bottom feed dog and top presser foot that pull the work back in sync. These machines are made to sew heavy vinyl and upholstery fabrics through the machine. Your Juki 1541 is a triple feed machines meant to sew leather. The only reason for there being serrated feet is that the previous owner had to sew some heavy weight or slick material that would slip under the smooth feet.

I use a special inline foot set on my Cowboy cb4500. The width is about 1/4 inch, or a little less. The presser foot sits behind the alternating inside foot and sews inline on narrow flanges. If your machine is a 441 or clone, you can get these feet from Toledo Industrial Sewing Machines, who are advertisers here.

The 5/8" is when the feet are lifted up by the foot lift pedal or knee lever. The needle must be fully up at TDC in order to lift that high. This high lift is so that thick seams and fur linings can clear the feet and needle when you position the work on the machine. Once the foot pedal/knee lever is lowered, the feet will alternate about 3/16ths of an inch up and down as you sew. The alternating action maxes out at about 3/8 inch with System 135x16/17 needles. Trying to sew thicker stacks may cause the bottom of the needle bar to hit the top of the inside foot, or even the outside foot if they are a narrow set. This limits the useful sewing height despite the specs referring to a higher lift number. I experimented and found this to be the case.

The 289 is still an upholstery class machine. As such, it can handle #138 thread with a #23 needle, or possibly #207 thread with a #24 needle. The maximum thickness would be the same 3/8 of an inch of soft to medium temper leather. I might be able to sew two 8 ounce pieces of bridle leather, but not hard veg-tan or latigo. I own a similar machine made by Singer. I use it to sew patches onto vests and hats. When I first got it I tried running #207 thread in it. The machine struggled and tended to jam up. It has no trouble with #138 thread. But, it didn't like hard veg.

Did you try searching our forum? I did and got this first hit: