friquant

Yes, do post videos. Have you done timing on your RB5?

In practice, yes. What I really mean by this distinction is whether they have a minimum speed or not, and the ones with a digital display seem to have a minimum speed. They're either not moving at all, or they are moving at least at their minimum speed. And by analog, I mean you can ease into the gas pedal and start out at a crawl. What is the minimum speed of the servo motor on your consew? It's easy to find a "digital" servo motor with a minimum speed as low as 200 rpm, which with a 45mm motor pulley gave me 111 stitches per minute with an 80mm hand wheel pulley. Your setup may be slower if your handwheel is larger than 80mm. If you want slower than that, they you either need a speed reducer, or an "analog" servo, or both. I don't work with thick leather, so I will let others chime in regarding whether you will need a speed reducer in order to stitch the thick materials you are targeting.

Found a solution for the slack thread not jumping through the latch. That is, set the thread check spring to begin adding tension at that point in the stitch cycle. Still do not have a fix for the thread being off the shoulder.

What materials do you anticipate sewing, and how thick? With your other sewing machines, which would you rather have: A. Slow gentle startup, or B. The convenience of a needle positioner? It seems that there are two camps of servo motors. With an analog servo motor you supposedly get slow gentle startup, but not necessarily support for needle positioners. With a digital servo motor you get decent support for needle positioners but you get a jerky startup. Some have reported that their needle positioners did not work when they added a speed reducer. If your servo motor has a standard 15mm cylindrical shaft with a woodruff key in it, you can buy an aftermarket 45mm pulley (75mm is standard) for about $10 to get some speed reduction.

My digital servo motor has the same problem...the foot pedal is still hot for about ten seconds after turning off the power. I'm thinking on how to bring it to full off sooner. So far my best approach is: Turn off power Grab hand wheel with two hands so it can't move Press the gas pedal and let the motor pulley spin to scrub off the energy I imagine with a clutch pedal one could take a gentler approach...hold the hand wheel with one hand and press gently on the clutch to scrub off the energy.

Having never seen one in person, I underestimated the amount of distraction it can be when in motion. needle-guard-small.mp4

Rereading, you asked for a list of potential pitfalls: Unplug the machine before you begin When you pull the hook out, make sure the pin for the bobbin case opener (under the hook) stays more or less in place. (you don't want to lose it) If the hook is stuck, reach for penetrating oil and a hot air gun. (I broke a hook once prying it out) Make sure the hook is properly settled into place before you screw it down. On my 341 clone it's fiddly to get the hook to drop into the hole because the bobbin case opener has to also align. When you insert the hook, it can go in two different ways 180 degrees apart. One works and the other will not pick up the thread Make sure the tang on the bobbin goes into the slot on the needle plate. Be very careful turning the handwheel if the bobbin is installed but the needle plate is not Magnetize your screwdriver for getting the hook gib screws out. These screws are tiny and easy to drop Use a new needle for timing and clearance adjustments (to make sure it is not bent) Set hook-to-needle distance before setting timing. When setting the timing, note the manual specifies the stitch length you should be set to. (Easy to miss) When setting the timing, make sure the timing gear is gently pressed against the other gear. When setting the timing, note there is a little play in the hook, so make sure the timing is checked during forward rotation of handwheel. Sometimes I use one finger on the hook to apply some reverse pressure to it. Make sure you readjust the bobbin case opener so the thread can jump through the latch, and so the bobbin case opener does not bind. Set timing according to the book. After you set it, verify that it catches the thread with forward and reverse feed, with both short and long stitches. Make sure everything moves smoothly and does what you expect before you run under power afterwards. Find out how your hook broke. Did it collide with the side of the feed dog support? (You can file some material off to give more clearance where it is likely to hit) Did it collide with the needle? (You can/should adjust the needle guard to prevent this)

Found two more videos relevant to this project: Uwe's Consew 225 hook timing video. (Different machine but useful for timing basics. Especially useful are putting black marker at the middle of the needle scarf (easier than measuring your needle bar height). And using a clamp on the needle bar to set your reference position. ) https://www.youtube.com/watch?v=1wNBPX8i524 Uwe's Needle Guard Adjustment video. (Different machine, but same concept applies) https://www.youtube.com/watch?v=9EWODLVlOxo

You can do this! Setting the timing is no harder than removing/installing the hook. You'll want to remove the feed dog so you can see the needle-to-hook relationship better. Do you have already the service manual? Here is a link: https://leatherworker.net/forum/applications/core/interface/file/attachment.php?id=139088 The service manual explains what the adjustment dimensions are, but does not actually go into the details of how to remove the hook. This video by Uwe will show you how to remove. (Different machine, but the removal of hook is similar.) https://www.youtube.com/watch?v=CfkGrz3OugA

Wow, congratulations! I've got a table coming to me this weekend with an old singer knee lift on it. Now I know what it will look like 😀 On my pfaff 545 I learned to grease the sliding plate that releases the tension discs when the feet are up...the knee lifter moved much easier after that.

I even drop tools onto the pedal and the machine says giddy-up. Not fair I say! Like @AlZilla, I intend to turn the machine off (and wait for the digital servo LCD to go off) before I thread the needle or touch the bobbin. If I'm doing more than that, I often unplug it from the wall.

How to buy or make a finger guard for a Juki 341 clone? I occasionally see photos of triple feed machines with finger guards, but the feet I bought do not have extra mounting holes for guards.

I've decided to give up on this quest for now. Putting the machine back together and time to get to building something. 🚶‍♀️

Is this to drive the machine or to lift the presser foot? I thought you were going to use the kick drum lever to tell a separate servo to raise the presser foot.

Ooooohhh... Can you post links to the servo you're using for this?

Beautiful table! A foot lift is activated by pressing down with your foot, a knee lift is activated by pressing to the right with your right knee. My Jiang Long came with both, but I had to ask how to install the knee lift. Here is the install video they sent me...the chain actuator reminded me of your singer. 937adbfd78d59f2d56efebcd9d6f1892.mp4

I'm in search of the perfect hundred-dollar servo motor. I've had two motors, both of them good but neither perfect. Here are some requirements that would make me happy: Distance in degrees between needle-up and needle-down should be configurable Motor should use standard 15mm cylindrical shaft with key hole, since a range of aftermarket pulleys are available for this shaft size There should be a long range of travel in the foot pedal between slow and fast The maximum speed should be configurable When the maximum speed is set to something slow such as "900 rpm", the range of pedal travel should be spread across the entire usable range. Meaning you should have to push the pedal all the way to get to 900rpm if 900 rpm is your max. Slow start, ideally, would be a gradual transition up from 0 rpm into some minimum speed. (The slow start I have used before still immediately jumped from 0rpm to 200 rpm, which was not gradual at all) When you tap the gas pedal to ask for one stitch, you should ALWAYS ALWAYS ALWAYS get exactly one stitch. If you give two stitches instead of one now there's an extra hole in the leather that I hadn't planned on. Also, giving more stitches than asked seems like a safety issue. When you heel-tap to ask for the needle to come up, the needle should come up. It must not do a full turn and then come up. That also puts unwanted holes in the leather and seems like a safety issue. The power switch must be in easy reach of the operator The power switch should light up so we can see when it's powered on When the power switch is turned off, the motor should immediately stop. (Safety) Pressing the gas pedal after the power switch has been turned off should have no effect. (Safety) Instructions for operating the manual should be provided in clear language. (I'd be happy to help you write the instruction manual) Ideally one could limit the amount of torque through the control settings There should be no settings visible in the menus that don't do anything. The settings in the menu should be numbered incrementally. No skipping numbers, as this is confusing. Ideally, needle position sensor would stop within one degree each time. Five degrees may be acceptable, but one would be better. If the gas pedal is pressed down while the power button is turned on, the motor should not start. (Safety) Rather, the motor should wait until the gas pedal is released and then pressed anew before motor starting. Ideally, the minimum speed would be 30rpm. This would alleviate the need for a gear reducer for many people. Though if small pulleys are available, 60rpm may be fine. The factory default maximum speed should be something medium slow like 1000rpm. Let the user increase it through the menu if they need it faster. If the belt slips such that the motor has to turn farther than it expected for the needle position sensor to register one complete cycle, the motor should stay in needle detection mode. Ideally, the needle position sensor should have an LED that lights up when the positioner is in the needle-down position. (Makes for easier setup) Assuming this unit comes with a needle position sensor, the controller should have needle positioning enabled by default.

Attaching pages 12 and 13 of the juki 1541 manual. After you adjust section 9 (horizontal feed cam timing), you will have adjusted it so that in a certain position, you can rock the reverse lever back and forth and the feed dog does not move. This is the position you will want to initiate your reverse stitches from. On a machine with a needle position sensor, you can set the position sensor to always stop at approximately that position. Needle positioner or not, I find it useful to have some clear markings on the machine and handwheel showing you when you are in this "reverse magic" position. Here's a picture of my alignment marks in blue tape.

Here is the geometry of the throat plate.

Repositioned the throat plate so that it aligns better with the overall shape of the cylinder bed, and adjusted the feed dog and needle positions to match. The thread now enters the latch cleanly about 60% of the time (Reverse, max stitch length), but the thread is no longer riding in the shoulder. (So many compromises!) The camera angle is different this time. I tried to get a directly top-down view (as close to orthographic as possible) to show the relative angles of things. The bobbin case is not square with the throat plate. I'm not sure if this is how it should be. I'm thinking on how I can test with different throat plate geometry to see if I can get the best of both worlds (thread riding in shoulder, with clean thread entry into latch) attempt-2__small.mp4

When I was learning to drive an industrial sewing machine, my favorite thing to practice on was actually corrugated cardboard. Ubiquitous, cheap, thick, stiff. You can cut two pieces and stitch them together. Or you can just stitch on one and make a pattern. At one point I was drawing curvy lines (with some tight corners and some loose corners) on the cardboard first, then seeing how well I could follow the line of ink. For practice, I enjoy having a different color top thread than bobbin thread. That makes it easy to see tension discrepancies.

Sounds frustrating. Here are some things to try: Does the machine turn over freely when bobbin and bobbin case cap are removed? (Can turn handwheel a couple revolutions to check no binding) With bobbin case cap in your hand, and the bobbin loaded into it, does pulling on the thread show smooth, even tension? With bobbin case and bobbin installed in machine, but no fabric under presser foot, does pulling on the bobbin thread show smooth, even tension?

Appreciate you chiming in to confirm. 😀 The edge of this shoulder is sharp, so it makes that we want the thread nestled inside the shoulder groove instead of dragging across its sharp edge. Originally (when I took the photos for the beginning of this thread), the feed dog movement was nicely centered in the opening front to back. Shifting it to the rear (away from the user) seems to make it so the thread almost always rides inside the shoulder groove. It's still very clunky though stitching in reverse at 4mm or longer stitch lengths. I'll do my best.. (Hats off to the videographers of the world that make it look easy!) Hopefully this will help to debug. I do love the sound and feel of a machine when it sews smoothly, and it seems I'll never get back to stitching until I unravel this mystery. hook-1-overall-export__small.mp4

In my original post, I reported that after setting the hook-to-needle distance to factory spec it was stitching fine in reverse. Well it's true that the hook is no longer bisecting thread. But it is quite clunky-sounding in reverse with long stitches. Here is a video that shows where it's still hanging up. 😢 This is stitching in reverse at max stitch length. 19-options-36.mp4

@MML Glad to hear the needle positioner is working for others too! I added a reply to the manual that shows how to access the hidden menus. The most useful piece so far is being able to set the upper bound on max speed. 🐎😀