Uwe

Just turn it over by hand to make stitches until you figure out what's going on. When I make major changes or adjustments I always check everything out first with hand-turned stitches before I even attempt to run it under power. A lot of bad things can happen under motor power that won't happen if you first turn the wheel by hand and observe, listen and feel how the machine works.

Does the Twilight Zone Theme play while this is all happening? That exact double stitch length in reverse is just too freaky. Make a video of that. The only real explanation of that would be a stitch length mechanism that's WAY out of adjustment. Is your feed dog movement correct after re-installing the cam? Check feed dog movements without any material and verify they make sense, both forward and reverse. Test sew a piece with NO thread, forward and reverse. If stitch length still changes it's clearly not the thread that's causing it. Does the material slip a little when the needle is above the material? That's the only time it really can slip. Perhaps the outer presser foot is not holding the material down with enough force to keep it from slipping. Thread tension does play into this to some degree. If thread tension is too high it may yank the material towards the needle a little as it's pulling the knot tight and pulls more thread from the spool. If the material is not slipping, perhaps the transport mechanism or linkage is slipping when the going gets tough or reverses. Make sure all the screws and bolts involved in the stitch length mechanism are tight. Does the stitch length lever move when this happens? That level should stay wherever you put it and it should not move as you sew.

Something like this Yamata FY5318 setup on CL might be a good candidate in your area. Nice looking garment class machine, table and a servo motor. You should be able to swap heads without major modifications (other than removing the Yamato's oil sump pan, which often just sits in the opening).

To make a complete setup, you'll need a tabletop with a suitable cut-out, K-legs with a pedal, a motor, and a belt. Most people who consider buying just a machine head already have a few machines and want to upgrade, or they've built or mixed/matched a few heads and tables and are not intimidated by the task. I wouldn't recommend going that route if it's your first machine. It's not that hard if you're handy and once you've done it a few times, but I can imagine it being very frustrating starting from scratch without a reference point. On the plus side, the industrial tables and motors are interchangeable to a large degree. The whole system is designed for the factory where if a machine fails, the tech stops by and quickly swaps machine heads to keep the worker productive, while the tech works on the faulty head in the shop. Motors are compact and easy to ship, they run about $130-$150 shipped for simple, good servo motors like the FSM-550 series available from the banner vendors. K-legs (or H-legs) are also easy to ship when they're in pieces inside a carton, like an erector set. Those run perhaps $80-$100 shipped. The table tops nowadays are cheap laminated particleboard affairs, but they're big,heavy, awkward and relatively expensive to ship. You're looking at $100-$120 shipped. Make sure you tell the vendor what sewing machine it's for so they know what cutout you need. The belt can come from your local hardware store or automotive parts store. Just about any "3L" type V-Belt will do as long as it's about the right length within a 2"-3" range. Getting the right length can be tricky and you won't know for sure what length you need until you have the table set up, the motor installed and the machine sits in the table. Lucky for me my local non-chain hardware store has a large selection of cheap ($6-$9) belts in 1" increments from under 20" to over 50" in length. I bought one belt at an automotive store and the poor clerk was utterly confounded after I couldn't provide a year and model of my car, and "I need a 3L V-belt between 40-42 inches long" did not compute with him. The total table+motor setup new from scratch runs about $300-$400 shipped. Not exactly cheap if bought separately. Package deals from vendors usually lower that cost to some degree, since everything gets shipped on one pallet. If you have a local-ish industrial sewing machine dealer, you can save a lot on shipping costs and probably get a complete table/motor setup for $200-$250. You can also scan local craigslist for a complete, cheap setup ( I saw a vintage $150 Singer, and a new-ish $350 Yamato with servo motor in your area listings) and then swap out the head and sell the original head again on CL ("Works! Sews everything!") I bought one machine simply because the table was beautiful and the whole setup was only $150. Again, I wouldn't recommend going that route if it's your first machine.

That Pfaff 467 is a strange design and you may have a very hard time finding parts for it. The Juki 563 and Adler 167 are very common with lots of parts available, both are very good designs with nearly identical capabilities and comparable quality. My advice would be to avoid the Pfaff and toss a coin between the Adler and the Juki (if they're in similar condition).

The common naming of the two springs adds to or creates much of the confusion, I think. My topic title doesn't help either, come to think of it. The springs and corresponding adjustment screw really should be referred to as big/major/rough adjustment for the big leaf spring in the back and small/minor/fine/incremental adjustment for the small coil spring because both springs affect foot pressure for both feet. The big beefy leaf spring in the back of the machine provides the big/major/rough pressure. It changes pressure for BOTH feet by about 4 lbs (~2kg) of pressure with each full turn of the adjustment screw on my machine as measured by the scale. The comparatively small and weak coil spring inside the head provides small/minor/fine/incremental adjustments for fine-tuning. It changes pressure for BOTH feet by about 4 oz (~100 g) with each full turn of the adjustment screw. So if either of the feet leave marks, you need to adjust the pressure of the big leaf spring before fiddling with the small adjustment spring. The generally smaller inner foot will show marks before the outer foot mainly because the inner generates a higher pounds per square inch pressure due to the smaller contact surface. Most people can probably safely ignore the fine tuning spring adjustment knob entirely.

I posted this on another topic in the Sewing Leather sub-forum, but I think it also belongs here since it relates to sewing machines and applies to most walking foot sewing machines. Also to open it up to discussion without hijacking the other topic. Here's my original post (with minor edits): Geek alert! I've been giving this some thought because that foot pressure business has baffled me for a while and the inner foot spring setting never had any noticeable effect no matter how I adjusted it. I've concluded that the inner presser foot spring has only little, incremental effect on how hard the inner presser foot presses down on the leather during the stitch cycle. Changing the spring or cutting a bit off will also have minimal effect. This sounds weird and counterintuitive but the OUTER presser foot spring ALSO determines how hard the INNER foot presses down when outer foot lifts up. The pressure of outer and inner foot are NOT independent of each other, in fact they're closely and quite literally linked. This is because the outer foot actually uses the inner foot as leverage via linkages to lift up, against the spring that controls outer foot pressure. If you remove the inner foot entirely, the outer foot will not lift up at all because it needs the inner foot as leverage to press against the material in order to lift up. I believe the main purpose of the inner presser foot spring is to ADD incremental pressure to the inner foot on top of what the outer foot spring already provides. Adjusting the inner spring will never allow you to lower the inner foot pressure below what the outer spring dictates. I just now did a little experiment to back up my claim with some proof. I put a kitchen scale under my presser feet bars and moved the needle bar up so as not to interfere. I dialed the outer pressure foot spring low enough to get below the 10 lbs weight limit of my scale. I removed the inner presser foot spring adjustment knob entirely, so the inner spring was not pressing down at all. With this setup and the inner foot spring totally out of play the outer foot bar pressed down registering 7.2 lbs: and after turning the wheel a little the inner foot bar pressed down with 5.5 lbs: The difference is likely due to linkage angle and lever lengths, but the two are proportional. If I dial up the outer foot spring pressure, so increases the inner foot pressure (all WITHOUT the inner foot spring involved at all) Adding the inner foot spring control knob and cranking it all the way down for max inner foot spring pressure increased the inner foot pressure an additional 2.5 lbs over the initial value. This is the max the inner spring can ADD to outer spring. The inner foot is also more likely to leave a mark because it has a much smaller footprint than the outer foot and exerts higher force per square inch with the same spring pressure (the skinny high heel of a shoe is more likely to leave a mark than the bigger front of the shoe, but your weight does not change as you walk.) So the small inner foot even at 5.5 lbs is much more likely to leave a mark than the bigger outer foot at 7.2lbs I'd try dialing back the outer foot presser spring until it just barely holds on to the material when you tug on it and see if it makes a difference. Help guide the material with your hands as you sew to allow the machine to move the material easily and consistently with minimal foot pressure. Don't push or pull as it sews, just allow the machine to do the work with minimal force. Sorry about the long and geeky post, but I hope it adds some clarity to this confounding foot pressure business.

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Geek alert! I've been giving this some thought because that foot pressure business has baffled me for a while and the inner foot spring setting never had any noticeable effect no matter how I adjusted it. I've concluded that the inner presser foot spring shown in your picture has only little, incremental effect on how hard the inner presser foot presses down on the leather during the stitch cycle. Changing the spring or cutting a bit off will also have minimal effect. This sounds weird and counterintuitive but the OUTER presser foot spring ALSO determines how hard the INNER foot presses down when outer foot lifts up. The pressure of outer and inner foot are NOT independent of each other, in fact they're closely and quite literally linked. This is because the outer foot actually uses the inner foot as leverage via linkages to lift up, against the spring that controls outer foot pressure. If you remove the inner foot entirely, the outer foot will not lift up at all because it needs the inner foot as leverage to press against the material in order to lift up. I believe the main purpose of the inner presser foot spring is to ADD incremental pressure to the inner foot on top of what the outer foot spring already provides. Adjusting the inner spring will never allow you to lower the inner foot pressure below what the outer spring dictates. I just now did a little experiment to back up my claim with some proof. I put a kitchen scale under my presser feet bars and moved the needle bar up so as not to interfere. I dialed the outer pressure foot spring low enough to get below the 10 lbs weight limit of my scale. I removed the inner presser foot spring adjustment knob entirely, so the inner spring was not pressing down at all. With this setup and the inner foot spring totally out of play the outer foot bar pressed down registering 7.2 lbs: and after turning the wheel a little the inner foot bar pressed down with 5.5 lbs: The difference is likely due to linkage angle and lever lengths, but the two are proportional. If I dial up the outer foot spring pressure, so increases the inner foot pressure (all WITHOUT the inner foot spring involved at all) Adding the inner foot spring control knob (the one in your picture) and cranking it all the way down for max inner foot spring pressure increased the inner foot pressure an additional 2.5 lbs over the initial value. This is the max the inner spring can ADD to outer spring. The inner foot is also more likely to leave a mark because it has a much smaller footprint than the outer foot and exerts higher force per square inch with the same spring pressure (the skinny high heel of a shoe is more likely to leave a mark than the bigger front of the shoe, but your weight does not change as you walk.) So the small inner foot even at 5.5 lbs is much more likely to leave a mark than the bigger outer foot at 7.2lbs I'd try dialing back the outer foot presser spring until it just barely holds on to the material when you tug on it and see if it makes a difference. Help guide the material with your hands as you sew to allow the machine to move the material easily and consistently with minimal foot pressure. Don't push or pull as it sews, just allow the machine to do the work with minimal force. Sorry about the long and geeky post, but I hope it adds some clarity to this confounding foot pressure business.

That thread ZAP 2 thing looks neat! A soldering iron with an adjustable heat setting may work, too. I find a lighter hard to control, especially when I try to melt thread in a tight inside corner. With the lighter flame method, my white polyester thread occasionally turns an unsightly brown as it melts/burns, and my leather got burn marks on occasion as well. Polyester thread melts at around 450ºF (230ºC). Most soldering irons are designed to melt soldering tin at 700º or more and leather will get burn marks at that temperature, too. I bought this adjustable soldering iron to test with because it can be adjusted LOW enough to just melt but not burn polyester, but I haven't really had a chance to try it yet:

My sofa has french style seams and the arm rests almost look like a tote design with a gusset to give it some useful depth. All the corners are rounded to make the french seam practical:

The straight seams are easy enough it seems, it's the corners that get you. I'm having a hard time picturing how this seam would work on a 90 degree corner like your tote bag. If you're using a flatbed machine you'll be wrestling that material pretty well to make it lay flat as you move along the seams near the corner. Cutting the bottom "corner" with a radius rather that a sharp 90 degree corner may be a feasible solution. Then you can sew the entire seam in one relatively smooth line with soft curves rather than sharp corners. I did a test piece for a french seam recently. It's just a flat T-seam, but at least it shows the concept of this style seam:

I still have it and my confidence is waning that the original buyer is in the position to follow through on the purchase.

Yup, belts are a different story. A 441 class machine would be a great, well supported and capable choice. The 441 class of machines is based on the Juki TSC-441, which is still available new for around $6K. Copies include Cobra 4, Cowboy 3200/3500/4500, TechSew 5100, Weaver Master Lockstitch, and a few others. The copies run about $1,600 to $4,000 depending on brand and accessories. Pick the best tool for the job. Your hands are the best tool for those shields. The 441 is among the best tools for the belts.

All better now. I took the timing belt off one more time and advanced the bottom hook drive shaft one notch. Then I re-timed the hook for the seventh time today - I'm getting the hang of it. Here she is sewing as well as I had hoped for: I'm gonna give her (and me) a rest before I tackle that confounding reverse mechanism to balance forward and reverse stitch length.

I certainly do enjoy blundering around in the dark, especially if the person I'm blundering with has great timing and knows how to adjust tension just so. @TinkerTailor: it sure looks like a rubber O-ring but it's actually metal and part of the threaded post. Not sure if it's a manufacturing or a design issue. I suppose I could just use a dremel and grind down the bulging ring: @ Gregg: Thanks for that suggestion. I checked that guide gib part on my machine and it appears to be doing exactly what it's supposed to. I actually made a good deal of progress this morning. I decided to put things together but leave out the broken thread release part. It's not exactly a vital organ and I can't see any reason why the machine should not function properly without it in place. I'll deal with the foot-up thread release manually, not a big deal. As I was putting things back together, I adjusted foot lift, timing of the inner presser foot (so it arrives at the material at the same time as the needle - it was way early before), re-timed the hook about four times with different top-bottom timing belt settings. Once I have it all figured out and can reproduce it reliably, I may make a little video showing how I made these adjustments. The machine actually makes a very nice, even stitch now, so I' think I'm about 90% there. The one thing that's still bothering me is that the thread seems tight wrapping around the bobbin and it snaps a little as it's being released from the thread cast-off nib on the hook (i cleaned and polished the nib, no burrs or anything). So it seems to me that I'm still just a little off on the timing to reach the buttery smoothness nirvana, but I'm not quite sure which adjustment will get me there. Should I advance hook timing a little or is this still due to an imperfect top-bottom timing belt position? I can't be far off. Here's a little video that hopefully shows what I'm talking about:

We'll get it worked out. I have the full Adobe Acrobat software to optimize and otherwise tweak PDF files for best possible quality at the smallest possible size.

The administrators of this site REALLY need to work on a mechanism that allows us to upload larger files for manuals and other special cases so we can share them with all users. Who owns this place?

Nice work on your hand sewing! I'm not sure using a machine will help you all that much - it may cause more trouble than help for your particular project. If each stitch line is only a few dozen stitches long and the stitches have to be as precise and pretty as your hand stitched ones, you *may* save a few minutes trying to use a machine but you'll almost certainly add and mountain of frustration over ruined badges/shields, messed up stitch lines and marked leather. You'll still have to finish the stitch lines by hand to get even close to your hand-stitched look. It seems like you put a LOT of effort into carving and otherwise preparing those leather badges and shields. I'd hate to see all that effort ruined by some machine at the very end. A machine that does very slow manual stitch placement like the Tippmann Boss line may indeed be one of the few workable options. I'd be tempted to make the hand stitching process easier or faster by creating some templates for stitch placement, or things along those lines.

Is this the machine that you broke two needles on yesterday? Maybe your safety clutch popped and timing slipped a little, or is still slipping as soon as the going gets tough? On my Tacsew, which was (and still is) having major timing problems, I noticed one setting where it made stitched, but the hook would occasionally catch the loop AGAIN after it had be pulled around the bobbin. If timing is off, no amount of thread tension adjustment will fix it. I'd flip the machine back and turn the stitches slowly by hand to make sure everything is happening exactly as it's supposed to on the underside.

Some progress and a little detour. I installed the machine in a new tabletop, installed the new thread tension unit today and added a servo motor. A normal person would have started to sew, but my foot lift tension release was not working properly and next thing you know: But I did confirm that one suspect part was indeed broken: The little finger that sticks up to align things had broken off. This is what the part is supposed to look like: The new part is on order and I hope it arrives before I forget how to put things back together. Here are a few shots of the two different replacement thread tension units I had ordered. The one with the grey plastic knob on the right is a little better than the one on the left, but not because of the bigger knob: What irritated me about the first one received was the significant offset between the two sets of discs. Ideally the two disc sets would align to let the thread go from one to the other smoothly. This design had a really big ball of sorts to attach the tension disc post to the plate. It pushes the tension discs away from the base plate and makes for a large offset. On the original tension units the discs are basically right against the plate (but it was totally broken, so it did me no good). The second unit I got was a little better in that respect: I'm dismayed that there is no service manual available for this particular machine. I suspect it's a LU-563N copy. The LU563N was the successor to the LU-563, and it was a transitional design that incorporated some design elements that would also show up in the next big overhaul, the LU-1508. I found a parts diagram for the Juki LU-563N which is indeed closest to my Tacsew T1563 clone. Unfortunately, I'm striking out finding a copy of the service/engineer manual for the Juki LU-563N. The problem is that key adjustment procedures like timing belt synchronization, hook timing details, presser foot timing, etc. for the LU-563 and the LU-1508 are totally different, and I'm left to guess and trial/error my way to what actually works on my machine. The adventure continues . . .

Not quite yet. I got side-tracked making that binding video on my Adler 205-370. I just carved a beautiful new white laminated plywood table top for her today and my replacement-replacement thread tension unit should arrive tomorrow. I'll have her mounted in the new table with a new servo motor on Thursday and then I'll check where I stand adjustment-wise.

There's also a version of the Engineer manual for the Juki LU-1508 (not "N" or "NH"). I'm not sure what the difference really is to N or NH version, or if they matter for your particular issue, but it's always nice to have good quality manuals for your exact machine. Juki has a really good online presence with high quality service manuals - gotta give them props for that.

Thanks guys. My machines are unnaturally clean because I spend way more time oiling and cleaning them than actually sewing with them. I'm working on that. I'm using the KHF-205 binder setup made by Kwok Hing in the videos. Overall a nicely engineered and manufactured set of parts, with two small flaws (I had to file the feed dog a tiny bit to make it fit the feed dog holder and the three-fingered tape guide touches the arm at full stitch length).

The hook part number is identical for Juki LU-563 and LU-1508 (B1830-563-0A0), so the hook oiling mechanism is likely the same. The bottom of the hook shaft/bushing dips into the oil bath and sucks up oil via the grooves in the hook shaft. It lubricates the hook and flings the excess oils sideways against splash shields surrounding the hook area, from where the oils drips back down into the oil bath pan. The felt pad or sponge in the pan is supposed to keep the oil from sloshing around in the oil pan and also acts as a filter to catch bits of thread and fabric that may fall down to keep them from getting sucked into the hook shaft. Whether this actually works at slow leather sewing speeds is another questions. It's designed to work running a full speed, I suspect. The little oil bottle that screws to the bottom of the big drip pan that covers the entire bottom is just collecting excess oil that may drip down from oiling all the other spots that need lubrication on the machine (other than the hook).