Members dmar836 Posted December 2, 2012 Members Report Posted December 2, 2012 So oiled everything and retarded the timing a tad. This time it took off with the motor just fine as usual. When I restarted by hand I felt it get bound so I flipped it up and the top thread was getting UNDER the hook and broke as the hook tries to take it around the second time. Hmmmm So I'm wondering, can the timing be 180 out? Since the hook spins twice for each needle bar cycle, could there be any advantage to retiming everything to have the hook meet the needle on the currently "wasted" rotation? Just spit balling, Dave Quote
Members dmar836 Posted December 2, 2012 Members Report Posted December 2, 2012 Just did it again using a larger needle I have determined that when this happens it is always after I have moved the material( in this case leather) a bit between stitches. So with the needle in the material I lift the foot a bit and turn the material maybe 90 degrees, maybe 180, maybe just a few degrees. It is when I then restart(usually manually) that I feel the hangup and the break occurs about the 2nd or 3rd stitch. I guess what I need to find is why is the slight twisting of thread around the needle is causing such a change with the hook action? Hmmmm Dave Quote
Members gottaknow Posted December 3, 2012 Members Report Posted December 3, 2012 (edited) You need to back up some Dave and set your hook timing back to what I call neutral. When the needle bar has risen 3/32", the point of the hook should be centered on the needle. I usually set the hook centered into the "scarf" of the needle, the very center of the dreppression. If your machine was 180 degrees out it wouldn't sew. Once you get your timing back to neutral, double check your latch opener. Remember, you want it to pull the basket just far enough open to allow the thread to pass the little tab without pinching. The felt for the bobbin runs up the center of the hook shaft. Don't worry too much about because you still have to oil the basket each time you use the machine of if it's been sitting for a while. Oh, and if your throat plate is worn out, the tab of the basket will jump out. Also, turn your material with your needle all the way down. Remember way back in this thread when I said to always keep in mind what your loop is doing. When your needle is all the way down, there is no loop. You turn your fabric, the needle bar starts to rise, forming the loop for the hook. If your needle bar has already began to rise, you can move your loop sideways, twist it around the needle, have the needle descend through the loop, breaking your thread and so on. Regards, Eric Edited December 3, 2012 by gottaknow Quote
Members dmar836 Posted December 3, 2012 Members Report Posted December 3, 2012 Awesome. I'll take another look at it ASAP. It also occurred to me that the thread could be less than ideal. I have been using 16/4 "button thread" which I have used with success on other machines. Perhaps that is another issue. Thanks a bunch! Dave Quote
Members dmar836 Posted December 3, 2012 Members Report Posted December 3, 2012 Retimed and played a bit after work this am. I can not, for the life of me, tell what would make the top thread drop down around the outside of the hook. The pointed tip clearly guides the thread into the recess of the hook but then somehow the thread occasionally, after manipulation from turning the material (even with the needle all the way down), ends up falling down to the base of the hook and around the hard cut edges on the bottom of the hook body. Of course it can't form a knot as it can not slip out of there. By the time the point of the hook is back around to the needle, the thread is stretched around that much longer path and snaps as the take-up lever ascends. I sure bet you are all tired of my posts and apparent takover of the is thread. I would seek local help but I'm beginning to think I'm about the best bet this day and age! Still suspecting the thread too so I'll need to experiment. Dave Quote
Members gottaknow Posted December 4, 2012 Members Report Posted December 4, 2012 Color me crazy, but in my experience, when your needle thread is slack or tight at the wrong time, your top and bottom shaft timing could be off 1 tooth. Even different thread shouldn't produce what I understand you're saying is happening. If I get time at work tommorow, I'll take a video of the relationship between the take up lever, the path of the thread, the latch opener etc. Having apprenticed several mechanics over the years, they all hit a wall (or several) on a machine. I would always tell them that "The machine you're looking at has the ability to sew correctly. It's like a puzzle. If you have a piece in the wrong place, even though it seems to fit at the time, when you get to the end of putting the puzzle together, it won't fit." You can have certain things off a bit, and the machine will sew somewhat. It won't be consistent however and will be "touchy". On an industrial machine in a factory, a machine like I've described gets taken out of service and replaced with a back-up until the correct adjustments are made. You've made a tremendous amount of progress in your knowledge of the machine. If you were my apprentice, I'd sit you in the shop with the machine and have you start from the beginning, Everytime you take a machine apart, you learn something. I still do. The bottom line is this Dave. If you can't get your machine working to your satisfaction, you can ship it to me, paying the freight both ways. I'll take it to my shop, put it in a table and set the entire machine. I will take pictures and videos as I go and make them available to this forum. I won't charge anything for my time as it will help kick off my project of providing training material. The freight both ways will likely be less than if you take it to be repaired somewhere. Just throwing the offer out there. As for hijacking this thread, I think there are so many 111 and 211 clones out there that your trials are well worth the bandwidth and may help others. Regards, Eric Quote
Members dmar836 Posted December 4, 2012 Members Report Posted December 4, 2012 I had thought as I laid down to bed that I was likely barking up the wrong tree with all the adjusting, testing, and readjusting the same parts. I did retime the shafts back earlier in this thread - moved it a tooth or two. Prior to that I don't remember anything more adverse than what's happening now. I need to spend the time to watch each area and understand exactly what is happening in relation to other areas. I also need to start at the beginning. I'm about to take my private pilot check ride and have been not only distracted but unwilling to dedicate unbroken time to the machine and related projects. Your offer is quite generous and I truly appreciate it but as with my cars, bikes, motorcycles, etc. I am all but unwilling to give up and let others do it. It's a hard head and pride thing. I'll get this figures out yet! Dave Quote
Members TSquared Posted December 4, 2012 Author Members Report Posted December 4, 2012 Eric, I couldn't agree more with your assessment of Dave's situation. I have the same philosophy as you, it is a machine and as such it has the ability of performing the job it was designed for. The only thing missing in Dave and my case is experience. I also agree with Dave about the pride thing. We both have the mechanical ability but lack the experience that you have. Your knowledge and patience has been so helpful over the past few weeks that I couldn't begin to thank you enough. The old phrase of "teach a man to fish..." is certainly appropriate. I have learned a lot from the help you have given to Dave, I just haven't commented because I am sneaking my Internet time at work. I have made a couple of small items this past week with some success. The cover for my Kawasaki zn1300 came out nice but the stitch lenght varies depending on the speed of the machine. It seems the faster speed produces a longer stitch. I am sewing two layers of Sunbrella and it seems like I don't have enough presser foot pressure to move the material. I would have thought the needle would advance the material in a uniform manner. The knob for spring pressure is turned all the way down so I am assuming I missed an adjustment somewhere. The video you mentioned would be extremely helpful to me. Since I have no experience with this machine, I don't know the relationship between the different parts. As to Dave's issue with broken thread, could this be caused by using the wrong size needle? While I did not break any thread, I could not get consistent sewing without getting thread wrapped around the bobben until I changed the needle size. I was using a needle about two sizes too small (I went from a 20 to a 23). The tip in this forum on how to test needle size to thread size put me on track. Gotta go, thanks again for your help. Tom Quote
Members dmar836 Posted December 4, 2012 Members Report Posted December 4, 2012 Tom, glad to hear you are sewing! I added some shims to the pressor spring on my Juki DDL - 552 and that helped but a "relaxed" spring may not be the issue with these. Interested to hear Erics ideas on that. Well, I feel I have the problem figured out. Did a cursory recheck of the shaft timing and all seamed okay. Did some fabric manipulation around the descended needle and could do nothing to replicate the problem or get the loop creation to fail. BUT I finally figured out why the issue occurs only when hand turning the wheel. BACKLASH. By hand turning the machine I am also unconsciously "throwing" the wheel a bit with the momentum. The hook stops first, then the balance wheel which unloads the whole thing. The play between the hook drive gears allow about 1/16" backlash which, in the middle of a stitch, allows the top thread to somehow drop further down the hook body and onto the seedy underbelly notchy parts of the hook body. I watched it happen and was able to replicate it. I am now convinced that whether the top thread is falling too far down the hook or getting hung up while trying to pull free of the bobbin itself, it is because of a moment of backlash. It is no less detrimental than a small snag somewhere. This makes sense considering how well it sews under constant motor power. The incident has been sporatic as only constant forward pressure on the wheel will ensure things don't temporarily slacken. Even sudden stops of the motor can allow the backlash to occur so restarting causes a snag. So, what to do? The gears themselves do not appear to have been abused and I can't see a way to adjust them to have a tighter mesh. Is there a washer, felt or otherwise, that fits on the casting just above the hook shaft bushing to somewhat dampen the hook movement? If so, mine is gone. I have to think that besides new gears, some form of felt friction washer under the hook will hinder it's easy backward motion without stressing its normal rotation. Then again, perhaps these gears are known to fail frequently and need to be replaced. I am now fairly sure this is what has been happening so that alone is getting me closer to the answer! Dave Quote
Members gottaknow Posted December 4, 2012 Members Report Posted December 4, 2012 A worn timing belt will create play in the hook. Regards, Eric Quote
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