Bugstruck

Well that's what three glasses of wine will do. Wiz is correct, my idea won't let the stitch form as the upper thread won't loop the core thread (bobbin). Hey, I was brilliant for about 30 seconds, in my mind only. LMAO now, at myselt.

Unless I'm completely missing something that 301 lockstitch and continuous bobbin feed thread path is fully achievable. Blows my mind nobody has figured it out yet. Not really a challenge compared to all the other machinery technology hurdles that have been long been cleared. Push the bobbin on a horizontal hook to the floor, then engineer the path. Barely difficult. Drive the hook from the side is the easy solution. With a gear under the hook and bobbin (as they all are now) it is rather more problematic but also achievable. Thread has to run the hook gear centerline in that instance, so a fight but surmountable.

135x17 is the same as DpX17 as I recall.

Found this. May be some help on the needle type. Start there. May have the right needle in it now and may not. Need the right needle to calibrate it. https://www.industrialsewing.co.uk/industrial-sewing-machines/needle-feed/necchi-840-136-industrial-cylinder-arm-needle-feed-machine

I really don't even know what say to that level of artistic ability. Yes sir, I am at a loss for words that are adequate.

Well you are reading info from the right guy. Wiz is a wealth of knowledge and good advice. If I come across as wise it is fully attributable to all the sharp tacks around here and the contributing machine vendors and real Leatherworkers who really know their stuff. Very helpful group of people and I'm thankful for what they contributed to my knowledge base. Always learning something new.

Luke, I would not part with that machine without giving it some serious thought. I had and still have old Singer home-type iron (cut my teeth working on and restoring them), then as my need to sew heavier products materialized, I got the Adler walking foot, then when heavier leather got in my blood the Cowboy 4500. Then I needed something less robust than either of them for wallet interiors and lighter work. Yep, needed a third machine and still looking. Believe me, they all fill a capability niche. Your machine and a heavy leather stitcher are a pretty good combo. Plenty the heavy stitcher is not well or at all suited for, even in leather. Certainly use it awhile before you unload it. You need a light to medium machine before you need any other, My experience anyhow. I'd learn and use that machine well before I got a heavy stitcher. Learning curve is fairly quick but what you learn on it will go a long way with other machines that are less set it and forget it oriented. Love my 4500 (Cobra would be the same) but even with all the prior knowledge I'd gained it took some getting use to. They throw a very wide range of thread and will handle a wide range of materials, very capable, so they take more time to learn what they like. Having good experience on yours will make that upgrade easier. Either way though, good luck in your endeavors.

Agreed with one caveat. Not all clutch motors feather well. One on my Adler just wouldn't, tried several things to fix that. The clutch on my 78-3 though is a dream to operate. A servo has nothing on it.

Your bobbin winder was for a leather belt setup I'd think. Haven't tried the new round belts, can't bring myself to it on vintage (leather belt) machines. Only appearance related here (others may like that look), they likely work fine and no doubt run cleaner than leather. I am not certain a needle position setup works with a speed reducer (I don't run any), ask Bob if nobody answers that. Speed reducer is best with a servo for speed control and penetration power as you know. However, my old Adler 67 flatbed with a small servo motor pulley, that setup works well enough for what I throw at it. Gets up to 1/4" vegtan on occasion but usually on the Cowboy at that thickness or more as it taps out at over 138 thread. The Adler wouldn't suffice for most pros in a volume setting for a couple of reasons but beyond okay for a hobbyist (me) with that small pulley setup. Something to consider. You could always add a reducer later and I don't see it as necessary until you are sewing thicker material and over 138 thread. Grab a few v-belt sizes if you are mounting a new motor and changing pulleys, I never seem to nail the belt length right the first time on a new setup. I'd also vote for less automation (needle position) if you are coming from hand sewing. Forces you to get familiar faster with the hand wheel and brake release. If you are like me you will not be a fan of a brake on any machine at the speeds we typically sew. Just an annoyance IMO but it does keep the needle parked, safety, maybe? I don't even buy the safety thing on an exposed belt. Perhaps of some actual use sewing fast on thin materials. I'd much rather hand break any machine.

Well that is a bit of a test for a that machine's ability to climb. I had that problem on a flat bed walking foot that was related to the feet not being balanced for lift so check that first. Inner and outer should lift the same distance or very nearly so. If that checks good your machine (others will be more familiar) may have an adjustment on the back linkage that will modify the range of lift. Solar will know. A mockup with scrap and a video of it sewing through the problem zone may help them diagnose. Rarely, I have to slow down and hand wheel through problem transitions, even on a well calibrated machine, giving it an assist and working methodically. Not sure if you sewed right to left but climbing that folded portion as the feet drop into that one ply ditch is closing in on the zone that give some machines more challenge than they want. The assist in that condition is to manually flatten that fold as the feet approach. Sometimes you can insert something narrow temporarily just before a step up and remove it as you work slowly through a tough spot. Give the leading edge of the feet a temporary (usually just one stitch) bridge to thicker material. I could get a machine less capable than yours, and otherwise incapable, over that jump usually. Someone else here always knows something I don't too. Good luck and expect a learning curve.

I recall a year or two ago coming across a German geotextile sewing machine, looking for something else. Was the size of a high ceiling room. All CNC programmable. Was circle sewing maybe 8 or 10 foot diameter tubing. Wish I would have saved the link. Most impressive I've seen online. Knowing CNC industrial equipment costs in wood processing, I would be surprised if that machine was less than $250K. The travel range or that sewing head was about unfathomable. Robotics. Most impressive I saw in person was as a teenager. Emblem looms at Lions Brothers. The sound was as impressive as the many bolts of fabric they had spooled up. Fabric was on the vertical plane. If I recall correctly one side had a low catwalk. I do remember a tech fixing a broken thread on the fly and my Uncle explaining it saved that emblem. I doubt those big machines are still in operation, all seems to be sewn on multi heads with the fabric horizontal now. The newer emblem machines, even the 24 head are much smaller footprint than they had there at that time. Was quite the operation. Around 1973.

Others who commented know this machine or variant, I do not. At say $650.00 though, based on the video and your comments, I would own it. You are correct. It is not close to a Cobra or my machine but where it works, it works. Just know what Gregg said is reality. The others have offered good advice too.

Is that 546 a double needle machine? Walking foot? This is probably not your problem but I'll toss it out as it may help someone. When feeding your problem fabrics, with plenty of material both sides of the presser foot, does the material self feed straight or does it want to sew and an arc? Doing close to edge sewing can sometimes be problematic. Bringing nylon into the equation doesn't help. Sometimes that is a stitch formation issue, not so much feed rate, although the nylon can impact feed rate somewhat, slippery. It should not be doing that to the degree you describe. What does occur sometimes, is that one paw of the presser foot sometimes contacts the feed dog plate before the other paw. This is usually more noticeable in thin material. Geometry is a little off on the outer presser casting (or feed dog plate a little bent) creating uneven paw contact and unbalanced pressure and drag favoring one side of the needle. Usually all it does is make the material want to turn instead of feeding straight and you can usually overcome that with how you control the fabric. When you have material under only one side/paw of the outer presser, you create a somewhat similar condition. I don not think that your feed rate variance issue is what I just described though. I'd guess you MIGHT have a small calibration issue between the walking foot center and outer presser that shows itself as the material thins up. Thicker material could mask that. My guess (if that were occuring) is the outer is cycling/lifting late. Before I'd go get into those weeds I'd play with presser tension first. Could be just that simple.

I don't think they carry Techsew parts. Been awhile since I've been active here but I believe Techsew or one of their dealers sponsors this site, used to. I'd certainly start there and if by some odd chance they can't get what you want you could PM me. You look to be a regular here, I think if one of the authorized vendors here sees your post, they would be inclined to assist. Someone here will know where to steer you rather quicker than I am presumably.

Call Bob, he may not have seen your reply.