Wizcrafts

If the presser foot is not going all the way down, lower the presser bar. There is either one or two screws securing it to the crank shafts that activate its up and down motion.

I'd hold out for a triple feed walking foot machine.

Do you have a user's manual and/or parts list. Have you watched it in slow motion while hand-wheeling it? Loosen the needles and reset them all the way up into their mounting brackets. If that doesn't fix it, one of the loopers may be bent, or pulled out of alignment. Also, make sure that it's threaded correctly and all the tensioners are set right. Sometimes, it helps to rethread these a-hole machines to get things working again. For me, it's a love/hate thing with sergers.

What material, thickness and diameter is the piping? Are you using a properly matched piping foot set? If it's thin leather, try rubbing Carnauba Creme on the area that's going to make the sharp turn before it gets to the feet. Or, apply it to the entire length in advance. Carnauba Creme softens and preserves leather and can be polished with a piece of wool fur. The added flexibility may help get rid of the corner wrinkles. If the wrinkles persist, try skiving it down a little thinner. If it's cloth or vinyl, check on upholstery forums, like https://www.theupholsteryforum.com/.

I have the 211g156 with reverse. The 211s are tough machines, but have small pulleys for high speed sewing of upholstery, boat/truck covers, tarps, tents and banners. My machine is at my shop. I'll take a look under the oil filler cover tomorrow and report back. I squeeze oil into every hole that isn't tapped for screw. You'll need the proper oil pan. You can probably get one from Toledo Industrial sewing Machines, who are advertisers here.

@keenbean To add to my previous comments, even if you are able to source thinner needles in system 7x3 - for a Juki 441 class machine - know that they are very long and easily deflected. With a lot of layers taped, glued, or stapled together there's a good likelihood that some deflection will occur. You can reduce the deflection by limiting the smallest needle to a size 20. This will poke a slightly wider than usual hole for #92 bonded thread, but it's still much smaller than a #23 needle. Since the 7x3 is a round point, the ends will still be on the surface, as opposed to leather point system 794 S point that submerges the ends. If you can live with a thread range of #92 through 207, a Cowboy CB3200 will handle everything you can throw at it. It sews 1/2 inch, but the feet lift 5/8 inch. I have seen folders on the Cowboy/Hightex website, which would be a special order. You can ask Bob Kovar, the owner of Toledo Industrial Sewing Machines, about folders and other attachments for that model. If anybody could fit one onto that machine, it's Bob. Addendum: I wrote a blog article about dumbing down a Cowboy CB4500 or similar class 441 machine for use with thin needles and thread. You might find it useful if you want to consider a CB3200, 4500, or similar machine. Note, most of the machines you're looking at are manually oiled. It's no big deal. It's a routine you develop.

@keenbean First, take a look at this thread and needle chart. It shows the diameters of various sizes of thread and needles and tells you which needle to use with a particular thread size. You really need to define a range of thread sizes, then find machines that can use the range of needles that are best matched to the thread. But, keep in mind that lockstitch machines for overlapping knots that must be pulled up inside the material without seeing them on the top or bottom. The thicker the thread, the harder it may be to conceal those knots. Different classes of sewing machines are able to handle different ranges of needles and thread. Most upholstery grade machines are meant to handle a range of thread from #69 through #138, with a corresponding needle range of #18 through #23. Extra heavy duty machines may extend the thread range to #207, which calls for a #24 needle. From your description of the range of materials and thicknesses involved, you will be on the borderline of heavy duty and super heavy duty. The Juki 1341 and its clones may or may not live up to your expectations. You want a 5/8" clearance under the foot (15mm). The only way you can get that amount of lift on a walking foot machines is if it is built to lift at least that high without the tip of the needle sticking out of the inside foot. The 1341 and its clones are probably not built with that extreme amount if foot and needle lift in mind. Ironically, the Juki LU-1508NH flatbed machine is built to lift that high, including the tip of the needle. It accomplishes this by using a longer needle system with a longer stroke. The 1341 and clones are made to use system 135x16 and 17 needles, with are standard length for upholstery grade machines. At their maximum rated lift, the needle bar just barely clears the lifted feet and the needle's tip is just inside the bottom of the inside foot. You'd have to ask a dealer, or somebody who has tried it to know if these machines can accept the longer system 190 needles that would be needed for a higher than standard foot lift. While the upholstery grade machines run out of lift around 1/2 inch, and are limited to a maximum thread size of #138, the 441 class machines are happy with thicknesses up to at least 3/4", with some able to sew 7/8 inch. However, these machines are built for super heavy duty sewing with large thread sizes and correspondingly large needles. As such, it is difficult to find any leather point needles under a #23, and even harder to find round points under size 22. These needles are perfect for #138 thread, top and bottom, but are way too big for thinner thread. Further, these machines have very large oval holes in the feed dog to clear needles up to a #26 or 27. Thin material can get pushed down inside the hole. To solve that problem, at least two people are producing narrow feed dogs and throat plates for the 441 class machines. So, you'll have to choose between modding a lesser machine to use a longer needle, then figure out how to increase the foot lift, or dumb down a more powerful machines to use thinner needles (if you can find any) with thinner thread.

I moved your post to the Marketplace section, under used sewing machines. Here is a good tutorial about adding photos to your post.

If there really are washers under the hook, removing them will advance the hook timing.

Either the latch opener arm is bent down too far or the hook is sitting too high up.

They're a brick and mortar business that's been in the same location for 28 years now. They have more parts than you can shake a stick at! Plus, it's a family run business.

Perhaps if you increase the search area to a wider radius you might see some desirable sewing machines on Marketplace. I found a lot more at 100 miles, and even more when I expanded to 200 miles radius.

@J Kellar There is another class of heavy duty sewing machine that can handle thick and dense leather, large thread and big needles. I refer to these machines as the 45 Class because they are based on the ancient Singer model 45. That machine was available with a fixed flat foot and with a flip up roller foot and had bottom feed only. I had one for a while when I first got into sewing heavy leather. It could handle #346 bonded thread with a #26 needle The maximum thickness was about 3/8 inch, although it could sew 7/16 in less dense leather. The modern equivalent would be the Cowboy CB2500, shown on this web page. You can read the full description there. It is a less expensive option if you don't expect to sew stacks of leather over 7/16 inch, or if tooth marks on the bottom and foot tracks on the top won't be a problem. Those marks can be pounded or rubbed out to a large extent. The main difference between a 45 class and a 441 class machine is that the 441s have triple feed that can walk up and down different layers without difficulty. The flat or roller foot would need you to lift the foot with the foot or hand lifter to climb up onto new layers. It would certainly handle knife sheathes and pancake holsters that only have two pieces being sewn together. Having had a Singer 45 and now having a Cowboy CB4500 gives me a good reference about the differences between these classes of machine. The only way I'd acquire another 45 machine was if I was going to be sewing tow straps or something else made of heavy webbing. You also asked about the best thread size for securing two layers of 10-11 ounce skirting. You'll definitely want to use #277 on the top and bottom. This calls for a #25 leather point needle and a lot of foot pressure.

Here is a thread and needle matching chart that I had a hand in creating. Where two sizes of needle are shown, use the smaller size in thin or soft material and the larger in thick or denser material. When it comes to the accuracy of the thread sizes, trust the name brands over no-name spools. Name brands have some degree of quality control. Avoid the cheapest thread (e.g., off-brands on eBay or online Marketplaces). The thread chart includes the strength of each thread size. This is its breaking strength. That can be used to determine the best thread for a particular job. For instance, if you are going to seam a cover that will be pulled tight over an object, or otherwise subjected to stress along the seams, use one size larger that the smallest thread. It might be a little harder to totally hide the knots on the backside, but the stitches may hold up better. I usually use the largest thread that allows me to bury the knots. There will also be different compositions of thread available to you. Choose the type of thread that fits the material. If you're sewing denim, you can buy a type of thread called Denim Thread. It's washable and stable when washed and dried. If you're sewing indoor upholstery, buy bonded nylon. If the job is for outdoor use, like a porch chair, or an awning, outside banner, or a cushion on a boat, use bonded polyester thread that's UV resistant.

That is an American Straight Needle harness stitcher. The machine is from the early 20th Century and has a needle and awl. They were made to use waxed linen thread. It was made to sew along the edges of harness and saddle straps. If you remove the edge guide, it has a depth of about 4 inches from the needle to the body. Here is a video explaining how to thread it and operate it: https://www.youtube.com/watch?v=vgt0AUp3emU