kgg

I figured I would mention the noise part as a lot of people live, sort of, in apartments and the noise / vibration of a compressor might make for unhappy neighbors. That should be interesting, you will become very conscious about all your electrical loads. If being off grid is going to be a new installation you will be better off, electrical wise, of over sizing your solar panels or generation. kgg

The price in France is really expensive as compared to what they are going for in Canada. The price for a used Juki LS-1341 in France at 2000 euro plus the cost of a compressor or $2930 CAD is a lot higher then what they can be had at a dealer in Ontario at $1650 CAD plus 13 percent sales tax for a total of about $1865 or about 1270 EUR. The one in the example comes complete with table and servo motor. Example: https://dixietailoringsupply.com/product/juki-ls-1341-used/ I would definitely ask to have the pneumatic system removed for three reasons i) expense of the compressor / hoses ii) more items to maintain / replace iii) noise and vibration of the compressor particularly if you are in an apartment which sort of defeats the quietness of having a servo motor. I forgot to ask how thick including overlapping seams that you will be sewing and with what size of thread? kgg

You may want to try putting the item under the presser foot so you are say about 3 stitches from the end and instead of sewing forward along the direction of your intended stitch line sew the item towards what would be the normal starting point, lift the presser foot turn the item and then sew back through those stitches in the direction you want to go. Doing that will lock the stitches and you will only have two layers of thread as compared to doing what a lot of people do when they a machine with reverse. Example with a machine having reverse: Typical way: Start the line of stitching, go three stitches forward then reverse to lock stitches then forward again to continue on doing the stitch line. Those first three stitches will have three layers of thread, 1 forward, 1 reverse and 1 one forward again. A method to reduce the number of layers of thread in those first three stitch holes is to start in 3 stitches on the intended stitch line, reverse stitch 3 stitches and then forward again too do the seam. So you get 1 layer of thread in the reverse direction of stitches and 1 layer of overlapping stitches in the forward direction to lock the stitches. kgg

How true. Depending on how the pneumatic presser foot lift was installed you probably could remove it and revert back to the standard mechanical operated foot lift. The Juki 1341 / 1342 came with both the front mounted knee lift and a foot pedal operated mechanical lift. What is the going price in France for a used Juki LS-1341 / 1342 machine? kgg

My take on the Juki LS-1341 / 1342. i) newer updated version of the Juki LS-341. A lot of the clones that are labeled LS-1341 are actually clones of the older Juki LS-341. Both the 1341 and 1342 have: The Same i) size cylinder bed 72mm (2.84 inch) diameter, ii) length of cylinder arm 255mm (10 inch) iii) large capacity bobbin iv) thread size capacity, rated for V138 v) needle system 135 x 16 or 135x 17 up to a 180 needle (#24 needle) vi) weight the same at 37.5 kg Their Difference i) Max sewing speed of the LS-1342 can sew 500 sti/min faster then the LS-1341 ii) LS-1342 has an optional smaller needle plate iii) The main difference is you can change the stroke of the presser foot and walking foot by a knob on the top of the machine for getting over multi layers Note: The Juki machines rate their machines for what thread it will sew with for both the top thread and in the bobbin not what size of thread you can stuff through the max size needle you can put in the needle bar. A 180 (#24) needle will take V207 thread and will handle it in the bobbin in thinner materials. This information is for the Juki LS-1340 series machines can be found on the Juki website: https://www.juki.co.jp/industrial_e/download_e/catalog_e/ls1340.pdf The information on the nameplate being scratched off is worrisome. Why?? The machine is missing a couple of things that I see i) Knee Lift probably because the machine is installed on some aftermarket or homemade table top ii) the bobbin slide cover is missing iii) bottom cylinder cover appears to be missing but it is hard to tell from the photo iv) Top thread post guide pin missing v) No thread stand for the top or bobbin threads You might want to check the main drive belt for wear as I see the bottom cover on the cylinder arm isn't seating quite right and may have been removed to do repairs. No kgg

A couple of more manuals for your machine: i) https://www.manualslib.com/products/Sunstar-Km-380bl-3906793.html ii) https://www.manualslib.com/manual/970676/Sunstar-Km-380bl.html kgg

Take your belt and go to either a sewing machine dealer, Canadian Tire or Homepot and either get a the proper 3V belt or a 3L general purpose belt. If you choose to go the measurement route add about 1 1/2 inch (37mm) extra to your measurement as the length on the belt is the outside diameter so you have to allow for the thickness of the belt. kgg

It often it depends a lot on where you are located, private or dealer sale and the operating condition of the machine. In Ontario, Canada you often see the Singer 211's go for about $500 CAD ($370 USD) and sometimes just the head for about $300 CAD ($200 USD). kgg

I agree with what @Wizcrafts said. Also you might try: i) Remove the wicks at the oil reserve end from the oil reserve and just oil those wicks manually. ii) Make up put a absorbent soaker pad (cotton / felt) to put in the pan. My LS-1341 clone didn't come with a catch pan so the oil drops would seep out under the frame onto the table top and leave an oily mess. The soaker pad works as long as I remember to clean / change the pad. kgg

The problem with the 335 machines they basically have a difficult time handling threads that are over V92 (T90, Tkt30) and some will not handle above V69 (T70, Tkt40). On this side of the pond, parts and accessories are expensive and not as popular as the Juki / Juki clone machines. I would on first blush pass and find a Class 1341 machine. kgg

What size of thread are you planning on using? Looking at the spec of the Cobra Class 26: i) it " sews up to 7/16 " and the thickness of 2 layers of 13 oz would be about 13 /32 which would only give you maybe 1/32 of freedom. Depending on the type of leather you are basically at the max abilities of the Cobra 26. ii) the Cobra 26 uses system 135 needles. With smaller thread and needle sizes you may wind up with needle deflection problems when sewing at the max thickness. I am not saying the Cobra 26 will not sew your items but if you are planning on sewing at the max capabilities of the machine regularly I would suggest moving to a Class 441 machine which would use the thicker 794 needles and wouldn't be struggling with handling the thickness of leather for your dog harness. The downside to that is for doing patches the hole size and feeding of the material maybe too aggressive on a Class 441 machine if it can be done. Since you are at both ends of the sewing spectrum I would suggest you look at two machines, one for putting patches on hats probably a 29k type or a post bed machine and a Class 441 machine for doing the thick leather. No one machine will do everything. I would also suggest taking a sample of the items you are planning to sew and visit a dealer. kgg

A good way to check what to expect in speed change by replacing the size of motor pulley. i) Checkout this site and just plug in the values at the top of the page. Imperial Values: https://www.blocklayer.com/pulley-belteng Metric Values: https://www.blocklayer.com/pulley-belt ii) If you need / want a speed reducer pulley setup just go farther down the page. Example: Change size of motor pulley 1. Motor speed 100 rpm, hand-wheel pulley size 4", motor pulley 3". The hand-wheel pulley will turn at 75 rpm's Change motor pulley down to a 2" and the hand-wheel will turn at 50 rpm's So you get a 1/3 reduction in speed. Install a speed reducer pulley: Motor speed 100 rpm, hand-wheel pulley size 4", motor pulley 3". The hand-wheel pulley speed at 75 rpm's Speed reducer pulley setup is either a single 6 " pulley and a single 2" pulley mounted a shaft or a 6" 2 step pulley that has a large 6" pulley and 2" pulley molded as one. 1. Leaving the original 3" motor pulley and the hand-wheel will turn at 25 rpm's So you get a 70 percent reduction in speed by just installing a speed reducer pulley arrangement. 2. If you also change the size of the motor pulley down to a 2" the speed will be further reducer so the hand-wheel will turn at 17 rpm's. The main question should be what is really a practical reduction in speed. I would be interested in knowing what the class 441 machines with a dealer supplied speed reducer installed actually get. kgg

A couple of things come to mind since your bobbin isn't rotating. Simple: 1) Safety clutch tripped due to overload on bobbin shaft. 2) bobbin case has slipped out of place. Did you reset the safety clutch on the sewing machine bed? Time consuming and expensive: 2) Drive / timing belt worn-out or broken. Tilt the machine head backwards and have a look underneath at the condition of the machines drive / timing belt. kgg

Might have been something for sewing heat resistant items similar to: 1) Para Aramid Sewing Thread https://www.textiletechnologies.co.uk/products/para-aramid-sewing-thread 2) Kevlar Stainless Steel Wire Sewing Thread https://www.eas-fiberglass.net/product/kevlar-stainless-steel-wire-sewing-thread.html kgg

I have no idea what this type of thread is normally used for. kgg

You should be pleased with the Cobra Class 26 which I think is a class 341 / 1341 machine. With a table attachment you should get the flexibility to be able to do most items. I think we all have bought a machine at some point that really didn't or wasn't capable of doing what we had hoped for. kgg

I maybe mistaken but the Tysew ( www.tysew.com) Wimsew W246 is a clone of the Juki DSC-246. I would make contact with them and see what the conversion cost would be. kgg

Personally like the A&E Anefil Thread which is a Bonded Nylon. I have never had problems A&E threads, their threads are made in both the Canada and the US and you can, at least in Canada, buy direct from them. The Sunstop from Sailrite is also an A&E thread a Bonded Polyester. Bonded Nylon is ever so slightly thicker then bonded polyester so the breaking strength of bonded nylon is slightly higher. Bonded Polyester handles UV and bleach exposure better then Bonded Nylon. My experience is the price difference between Brand name threads and the unbranded stuff can be substantial. The main problem is the consistency and quality of the no name threads typically Chinese stuff can be all over the board. Avoid the frustration and spend the extra for a brand name thread. The thread and needle are the inexpensive parts of completing any of your projects so it's better to start off with good quality. kgg

Before you go fiddling around with the machine change your needle to match the thread. The needle should be a #24 or in thick / tough material a #25. A good reference chart for thread and needle combination : https://www.tolindsewmach.com/thread-chart.html kgg

In your very first photo their is blurred image of your main spool which appears to have some form of thread banding around the cone in the center in the center of the spool. Could you please post a photo of the main thread spool and how you have threaded the thread through the thread post guide. Is this a recent problem that started to happen when you changed spools of thread. The thread appears to be a Chinese brand of thread which I have found to create weird problems caused by poor manufacturing. I would also. i) Check all surfaces where the thread passes through or around for sharp edges or grooves and ensure the needle isn't slightly twisted towards the front or back of the machine. ii) Change the needle to a #21 as the thread maybe sized different then what it is labeled as. iii) Change to a Schmetz brand of needle. I have had better success with their needles iv) Change spools of thread as it maybe a bad spool. v) Remove the banding around the center of the spool of thread as this maybe causing inconsistent thread tension. vi) Make sure you have a distance from the top of the spool of thread to the thread stand guide hole that is twice the height of the spool thread kgg

I have never seen a data base that lists the model with a cross reference to the year of manufacture for the Juki machines. kgg

Just to add to what MtlBiker said. What size and type of needle are you using. Should be a #19 or #20 with a 135 x16 needle. Is the machine threaded correctly for the top thread path and the direction the bobbin spins in the bobbin case as it unwinds from the bobbin? Is the needle threaded correctly, the needle insert all the way and in the correct direction? Did you do a drop test on the bobbin and bobbin case to get the bobbin thread tension set correctly? A few photo's would help of how you have threaded the machine from the thread spool to the eye of the needle. kgg

Just to add to the confusion. i) V138: Bonded Nylon has an average manufactured thickness of 0.41 mm while Bonded Polyester has an average manufactured thickness of 0.38 mm ii) V138: Bonded Nylon has an average manufactured strength of 22 lbs while Bonded Polyester has an average manufactured strength of 21 lbs iii) Bonded Polyester handles UV and bleach exposure better then Bonded Nylon. kgg

The upholstery grade machines have about 1/2" presser foot lift but you have to subtract about 1/8" from that for sewing purposes. This means you should be able to sew about 3/8" of material depending upon such things as how tough, how sticky the material is, needle thread combination, etc. Yes there is a large price jump once you go above the capability of sewing consistently greater then 3/8". Yes Juki does have medium duty machines that are rated for 3/8" like the compound feed Juki DNU-1541"S" flatbed and the compound feed Juki LS-1341 cylinder bed but once again if you are consistently sewing in the 1/2" or greater you are probably going to run into the similar problems. The compound feed on those machines (needle. feed dog and presser foot) will help to move the material along much better then the ordinary walking foot machines. The price of those machines: Juki DNU-1541"S" about $1800 USD and the Juki LS-1341 about $5500 USD. If you can figure a way around reducing the seam thickness like skiving by hand or by machine to be around 3/8" or under then i) price of a new machine becomes reasonable ii) you may not have to replace your existing machine. kgg

I would first suggest taking a sample of the thickest, including seams, of material or leather to a machine dealer and test drive a few machines. I would in a flatbed suggest looking at compound sewing machines that have the minimum sewing capacity of the Juki 1508 NH but you maybe once again be at their rated sewing limit. Once you get into needing too sew 1/2" thickness you are really, I think, needing a Class 441 machine. That would in a flatbed probably put you into a Juki TNU-243U or a Juki TSC- 441 cylinder bed with a flat top attachment. Both machines are grossly expensive probably north of $10,000. For most the cost is prohibitive so I would suggest looking at machines similar to the Cowboy CB 243 flatbed or in a cylinder bed the CB4500 with a flat top attachment. The cost of those machines are probably in the $3000 to $3500 range. I would stay with Juki or clones as accessories, replacement parts are cheaper and more readily available then say PFAFF and Alder. kgg