dmar836

I wish I could help. He will have to chime in on this one. So is the needle centered in the vibrating foot? After you mentioned the needle bare hitting it, I wonder if something got bent somewhere? Dave

Hmmm, Is the needle not centered? Maybe Erin knows differently but I didn't think the feed dog was adjustable side to side. I would look first for a bent needle as that's easiest. Looking underneath at the fork that runs the feed dog and the associated shaft above, I see no adjustments but could be wrong - perhaps the screw on the end of that shaft is an eccentrc. I suppose the needle bar or needle bar frame could be bent from a hard stoppage? How far to the side of the hole is the needle? Dave

I wondered what could make it want to roll back a bit when I stopped sewing only when in certain places in the sewing cycle. I thought first the drive belt being old and stiff. Of course it dropped the loop around the hook even without the belt. I then thought it could be something spring loaded. Everything we have discussed was timed and working but the feed mech always sounded violent. You guessed it, the feed pressure was so great that when the pressor foot hit the material, it was so over clamping that the spring pressure was acting as a resistance to the following cycle - the ascending needle. The early hit, with its high spring pressure, gave enough resistance to "get past" that, unless I was constantly on it, would cause a slight relaxation backward. This was just at the stage where the point of the hook had reached maybe 90 degrees past catching the top thread when then backing off allowed the thread to partially fall - frequently getting under the hook. Now, with no excess back pressure, the hook stops cold and the top thread stays planted on the hook point regardless of location. I also centered the needle in the feed dog and spaced the needle bar from the pressor bar according to spec as well. I still have concerns with adjusting pressor foot height. Both are now lower than before. I adjusted the gib so that they are more equal. Is there just one overall height adjustment for both feet and then just the one gib screw to balance the pressor and walking feet heights relative to each other? All the help has been phenomenal! Dave

Got it!

I played with timing and retarding helps a bit. I watched this am as I hand turned the wheel and it is happening at about 1/4 turn of the hook after it has picked up the top threaad. When I let go of the wheel the entire mechanism - hook to handwheel backtracks a bit. That is allowing the top thread on the hook to become slack and the bottom of the loop to fall down under the hook body. The to of the loop on the hook is picked back up and continues as it should. This ends up with the top thread around and under the hook body. Now I have to find what is physically making the machine spring sightly into reverse when forward pressure is relieved. I'm getting there!

You've mentioned it for sure and you'd be a great mentor. It is something subtle going on. The shaft timing is good. The hook and needle bar I have adjusted numerous times. This eve I reset the gears one at a time to see if shifting the set screws on the groove in the shafts helped. I did move the hook gear once before to allow extra adjustment but never strayed from the groove. Tonight I jjust changed which set screw lined up with the groove(and swapped screws) so that was probably 5 teeth. The needle bar couldn't be adjust to get it timed right so back the way it was. Really it sews fine, makes good stitches, and responds to thread tension adjustments appropriately. So I think it is subtle. I may have inadvertently jumped teeth when I had the hook out so I might mess with that too. I know I can get it! Dave

That took about 2 minutes and removed much of the slack. I still have play at the hook and it is stitching well except for the stop-start thing even without turning the material. I was going slowly and then doing some hand turning of the wheel and felt/heard a slip. Flipped it up and the top thread was under the hook body. It couldn't slip off to form the knot as it was actually around the bottom of the hook. I can watch it stitch fine into air when I go slowly and keep tension on the loose thread ends. Any other reasons why the hook would be allowing the top thread, while pulling it around, to drop the bottom half of the loop under the hook body? There appears to be a need for some additional resistance from the top thread so that it stays longer at the end of the hook point. The take up arm is still moving down when the hook has turned more than half a rotaion. Seams like the take up arm moving up slightly earlier would provide the needed tension and help set the stitch earlier. Could I readjust the needle bar height and appropriate hook timing to allow for this? My needle bar had no mark so I'm wondering if the PO or I have that way off. Or maybe I'm beginning to show my ignorance of these machines again? Dave

Great stuff. Weather kept me from the check ride but got the oral exam out of the way. Tonight I'll adjust the clutch and see what paly is left in the hook. Dave

Wow! Awesome video. It's exactly what I needed. This will isolate the play to the hook gears so I can really assess hook timing and that backlash. Maybe that alone will keep the top thread from slipping up or down. I watched a 70 or so part series about rebuilding a Maytag washing machine engine and wonders how cool it would be to have an ongoing series like this about working on these machines. Tall order for sure but you are very informed with a dying skill. Gotta love vintage engineering! Thanks, Dave

Well, cramming for my checkride has begun. I won't be available to play with it until Friday eve. Dave

Took a look and I can see and feel no play at all in the belt which is quite tight - not that under load it couldn't drift if the teeth were worn. Where I can definately see and feel play is a slight amount at the clutch mechanism but most easily at the hook drive gear interface. Looks like maybe I should drop some cash on gears and belt. Not sure if that will completely eliminate the gear play but I see no other way to adjust the lash. Is there a way to address the clutch play? All I remember reading is "don't mess with it as it is set at the factory." Dave

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

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

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

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

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

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

Yeah I tried that. There is no "felt strip" anywhere on my bobbin as shown in the various manuals. I'll look at the timing again as we'll but that's where the breakage is occurring just as the take up arm is rising and the top thread is hanging up somehow when that slot is exposed by the groove in the hook. It all gets very tight just before the break.

Mine is now sewing and I have run it a decent bit BUT I notice that it is starting to break top threads again as the thread slips out of the slot in base of the bobbin to form the knot. It appears to hang in the slot and just keeps traveling back into the groove in the hook about parallel to the needle. It is supposed to end up down in the small slot in the bottom of the bobbin isn't it? It appears that the hook takes the thread at the needle and passes it into that small bobbin slot and that it comes out of that slot about the time the slot is back around at the needle. No amount of opener adjustment seams to change it. I do admit need a new plate with a better defined notch on the bottom. Interesting thing is this happens only when I hand turn the machine as in around a curve or when restarting by hand. If I just take off with the motor it won't do it. I sanded on the bobbin "slots" last week when I discovered that is where it was breaking theads andit began behaving. It is doing it again now and I wonder if the slot(which acts somewhat like a hook) is grooved at the base and holding the top thread too long. It this a common sign of a worn out bobbin or am I confused about where the top thread is supposed to track? Dave Wow, I can't type!

Well I polished the hook and retarded the timing. My advice to anyone is to check and recheck timing, etc. as there is accumulated slack in everything. On a new or rebuilt machine, maybe not so much. I did some stitching with one tread breakage but after dropping the needle bar again and retarding the timing a tad it's working. One issue is that there appears to be a double row of stitching underneath my first project stitch - a leather hat visor. It is the first time I got through it without any thread breaking but there is the occasional extra loose stitch visible on too and a complete "follower" thread underneath the entire length of stitching. Any ideas? It's getting there! Happy Thanksgiving to all, Dave

So I adjusted the opener, the needle bar again, the tension, and the hook timing in about 3 more settings. Polished the underside of the throat plate as well. Still breaking a loop but only when I am hand feeding the wheel or transitioning back and forth from motor to hand-wheeling slowly. When I felt it tighten a bit I flipped the machine up and watched on two occasions. I see exactly what is happening. The top thread loop is almost formed around the hook body and just before it can slip off the hook into a knot, it pops apart. As it breaks I can just see the needle again penetrating the bottom of the fabric for the next stitch! What is breaking is the prior stitch that has not yet formed a knot underneath. My question is how can it stitch well when going full bore or even at a controllable steady speed but then when really slow or when fed by hand the stitch hook hasn't eenough time to get fully around before the needle is coming down through the fabric again? I wonder if it is catching on the back edge of the needle guard or some other slight protrusion only when slow as when faster the thread is whipped around it without snagging? I notice it does "bump" over the bobbin bail slightly when going slow and noticed the same of the needle guard a while back. I just never see it as it happens. Otherwise It sure is odd that only one stitch in 50 to 150 stitches suddenly appears retarded. NOw it's getting interesting. Dave

Have I officially hijacked Tom's thread yet? I was using the same thread with different colors while testing. I switched the top thread to a matching color and now I'm breaking top threads again. I watched and I am occasionally leaving a loop of top thread under the plate and when the hook comes around it snags it. This happens after about 7" of good stitching. Could it be the thread controller? It appears to be the hook cutting it and not the needle. In fact the needle isn't in the plate when The thread snaps. I have played with most of its adjustments on the thread controller but They don't appear to change anything. Dave

Thanks a bunch! Dave

Eric, What are your thoughts on replacement parts for these older machines? My feed dog and throat plate are certainly worn and the underside of the plate is smooth but kinda chewed looking(as you suggested might be the case). It all works but I want to tighten it all up a bit. I fear the plentiful inexpensive parts out there are junk that either have poor tolerances and don't fit well or will wear out quickly. Are the Simanco parts unobtanium or are the cheap replacement parts okay? Dave

Well, know it is appreciated and this info lives on and will undoubtedly help others in the future as these machines resurface. For me I prefer to see these tools utilized rather than running out to buy the latest plastic covered beast made in China. Good as they may be for a modern factory, there is something about these vintage machines that, who knows, may have been used to assemble flight jackets, military clothing, sails, etc. the mechanical workings - often visible - are ingenious and like art to me. The parts appear to wear so well that there is no reason not to keep them running. You mentioned in that video making another with adjustment info. That would sure be a boon to know there is info out there that reinforces the sequence of adjustments as I have seen the order is as important as the adjustment. Dave