spectre6000

I've also done some UV exposure testing on vegetable tanned leather, but not thread. The testing is all done (nearly 60 full days' worth), I just haven't done anything with the samples yet (they're all packed into the same spare room for forgetting purposes). I'm not sure exactly how you would do a realistic abrasion test for thread. It doesn't seem as simple as just taking sandpaper to it... There is an industrial standard, so someone has already figured it out, but I've not looked into it at all. Linen was the clear natural fiber winner for strength, which I know won't come as much of a surprise to some, but now there's actual context and some idea of relativity. This is pure conjecture, and as demonstrated above, is apparently not my strong suit with this sort of thing, but I think since linen thread is used in shoes, it's probably pretty decent on the abrasion side of things. I think I read that it has good uv, abrasion, and mildew (for another testable element) resistant properties, but that may or may not have involved waxing...

Premise: Part of my attraction to leather and leatherwork is that it's a natural material. Sewing it together with plastic thread sorta defeats the purpose in my view. I did a ton of research a while back into various natural fiber thread options, and, as I'm sure many of you are at least peripherally aware, there's not a ton of really solid info out there and it's in a huge variety of non-correlated terms and units. So, I did a little leg work, made a bunch of phone calls, ran all over town, ordered a few things online, and came up with a wide variety of threads to test, then sat on it for a few months, then moved the pile to an unused room because I needed the space, then eventually forced myself to scratch it off the to-do list. Methodology: Pretty simple really... I tied a bucket to a pry bar without any sharp bends in the knot, suspended that on a fender stand, then slowly filled the bucket with nuts and bolts out of my spare/used hardware bucket one small handful at a time with a healthy pause in between. Once the thread broke, I weighed it on a calibrated scale (.25# granularity), and recorded the result. Repeat down the list. Subjects: I was primarily interested in silks, because I thought that was most likely to be the strongest natural fiber I could get my hands on. I couldn't find reference to silk being used in leatherwork beyond aesthetic embellishment, but also couldn't find any reason for that to be the case. It's a commodity fiber, and not a cheap one, so my suspicion was that it was just too expensive and variably priced to gain much traction in industry, and thereby hobby-land. Since cost is not in my top XXX consideration list, it didn't seem a deterrent. I located a silk importer (one of the very few in the country happens to be semi-local to me!), and got a bunch of samples. I also tried "beading silk"; a lower overall quality, but more uniform industrially produced product. Unfortunately, it's difficult to impossible to find in larger quantities, but I figured I could track back to the producer if it was worth it. I obtained a variety of linen threads of various numbers of cords, and both Barbour and generic. I also gathered the stand-bys, nylon and poly, in 69, 92,138, and 207. I ran across a small spool of Kevlar in my hunting, so scooped it up for giggles. Hypothesis: My sincere hope was that one of the silks I could get my hands on in nominal quantities would be on par with the poly threads (the presumed non-Kevlar strongest). I really had no idea, just a hope. I expected the linen to be fairly mild. Nylon was expected to be a bit stronger than the polyester. I thought Kevlar would blow them all out of the water. Fortunately, the experiment was structured such that my pre-conceived biases had no effect... because I was pretty much wrong across the board! Results: Doing my best to recreate the spreadsheet here... Thread-------------------------------------------Breaking Point (LBS)--------Notes Kevlar.................................................................2.............................................Very fine, guessing ~38 #1 Silk................................................................4 Slik "Lixue"........................................................4 #2 Silk...............................................................6.75........................................Guessing ~92 thickness equivalent 69 Polyester......................................................8.5 69 Nylon...........................................................8.75 #3 Silk THEORETICAL.....................................9 Silk "Chilali".....................................................9...............................................~138? Silk "Neva"......................................................10.5 92 Nylon..........................................................10.75 4-Cord Unbranded Linen................................11 92 Polyester.....................................................11.75 #4 Silk..............................................................12 3-Cord Barbour Linen THEORETICAL.............14.25 5-Cord Unbranded Linen.................................15.75 138 Polyester...................................................15.75 138 Nylon........................................................17.25 Waxed Nylon? 3-Cord (leftover Tandy?).........19.5 4-Cord Barbour Linen.....................................19.5 207 Nylon.......................................................20.25 207 Polyester.................................................21 6-Cord Unbranded Linen..............................24 5-Cord Barbour Linen...................................25 6-Cord Barbour Linen...................................32.25 Conclusions: Like I said... It's a good thing I checked, because pretty much everything I expected to happen wasn't even close! I wasn't able to get my hands on #3 silk very easily for some reason, so I calculated a curve across the other numbered silks, and that's roughly where it should fall. I did the same calculation for the 3-Cord Barbour Linen (used to test something else a while back, and I only had about 6"), and checked my % delta against a published tensile strength chart, and was within 7%. With a sample size of one and so few data points to fit the curve to, I figure that's not too bad. I was super shocked by the Kevlar... I thought that would require a bigger bucket (and even switched to a bigger bucket in anticipation), but it didn't like it at all... I tried a second time, and had the exact same result. Both times broke at the knot, and it was the finest thread I tested, so that could have something to do with it. I had a ton of other exotic silks and silk-animal fiber blends (including camel and yak just because I happened upon them) blends, but they were all so weak that I didn't really feel it was worth boring anyone with extra lines on the spreadsheet. The unbranded linen was supposed to be at least as good as the Barbour, which has supposedly gone way downhill and is made in China or some such now, whereas the unbranded stuff is Ukrainian or something... Nope. You get what you pay for there. Sometimes the markup is for marketing, sometimes it's for quality. This is the latter case. Application: If I need big strength in a small package, it looks like I'm using Nylon. If I need strength with UV resistance, it's polyester. I thought Nylon and polyester would be a little different in strength, but they're neck and neck the whole way. The silk was a total bust, so that rabbit hole will be filled in. For most things, I see people/companies using 92 or 138 threads, and the 3-Cord Barbours falls right in the middle there without being too visually obtrusive, so that looks like what I'll be using for the most part going forward! I shared this because, while most probably won't wade through all my floral prose, it might help some like minded person down the road not have to go through such a task. At least it's all now in the same place in the same units with the same methodology for relative comparison. Enjoy.

The stuff I have here is equivalent to about size 277 thread (0.60mm), and heavier is available. If it's a matter of perceived availability or perceived cost, that would make sense, but I can't find anything suggesting any other reasons it's not commonly used. Admittedly, I'm grasping at straws for those reasons... It doesn't seem to be in most people's consciousness in the first place beyond rare and fleeting examples of decorative embroidery-type stuff on the sort of high end stuff where decorative embroidery type stuff is a thing.

Too heavy how?

I have some silk thread that's slightly thinner than 3-cord linen (which I also have on hand along with similar thicknesses of polyester and nylon). Maybe a little thicker than #138 polyester. It looks and feels great. I talked to the local industrial sewing machine place, and the guy I talked to said machines should have no issues with it, but that he's never actually seen such thread in use (or at all). It's also worth noting he's a textbook salesman of the say-anything school. Is there any reason I can't find anything about silk being used to sew leather outside of rare decorative applications? Is it just cost, or is there any physical/mechanical reason no one uses it?

Read all of what you highlighted, and the next sentence. Focus on what I'm calling attention to about those sentences in the parentheses. I'm not interested in a particular machine, I'm interested in the differences between them and why they matter. Take one step back from the vantage point of "what are you wanting to sew?", and ask why that question matters and why you answer it the way you do. What do you know that allows you to answer the question that I don't know and is causing me to have to ask it? I want to see the forest, the trees don't matter. If I said "wallets", "belts", or "saddles" your answer would be "X", maybe "X" again, and "Y". In this case, the "X" and "Y" are incidental. Does not matter at all. I don't care if it's a Cowboy 4500, a Sailright Ultrafeed, or a Cuisinart. I want to know what it is that makes them viable answers to that question so that I can make my own informed decision. Really though, I'm obviously doing a terrible job trying to get the question across, because everyone is getting stuck on that.

I never said the money was an issue. My budget is $what-the-right-tool-costs. I just saw a video with an unintentional closeup of the innards of a [name redacted because they're a forum sponsor, and I feel I've made enough bad waves already] machine. Between the poor casting quality of the housing, voids in some parts around the bobbin, what looked like either some pretty extreme wear or bad machining, and plating defects in a supposedly showroom new machine, I'm thinking hard about dropping the dime on a real Juki... That is, if I can lay eyes on the business bits of one to confirm that's not the case with the Juki. I told one of the guys on the phone that I'm more than willing to drop the extra dollar for quality.

My budget has plenty of room for the Sailright, but I think I'd spring for a cylinder arm machine. I don't have any problem with a Cowboy 4500 collecting a little dust if it's the right tool for the job when I need it. I have a pretty expansive man cave(s). Fortunately, I've been down the road enough to KNOW that I only know enough to be dangerous. That's why I'm asking so many questions. Since it's finally a business day, I called a few dealers. I got a lot of questions answered, but I'm left with more than I started. The first decision point, as has been discussed here, is thickness of material. Beyond that, it's all just different flavors of popsicle and they'll all get the job done. I know there's considerably more nuance than that, but since any dealer only sells a line or two, they can't really offer much more. All of the heavier duty machines were Juki 441 clones, so that is a bit more apple to apple. Here's where things got confusing: As anticipated, when talking to salesmen you get all manner of different answers to the same questions. For instance, one guy said Jukis are still made in Japan, one said only certain models are (not including the 441), and one said they're all Chinese. One guy said there are no currently manufactured German machines. One guy said the medium duty machines were 0-3/8" and the heavy duty machines were 0-7/8" with total overlap, a few guys said the heavy duty machines were only good down to 3/16". One guy said the medium duty machines were only good to 3/8" IF most of that was "compressible" (like upholstery foam), and 3/8" veg tan would shut it down. Is there any light to be shed on any of these discrepancies?

You're right about bumping heads. Thank you for listening to what I'm asking and responding thoughtfully and encouragingly.

Seems you don't understand.... Everything you just said applies equally to cars, yet I just typed out a paragraph off the top of my head to roughly the effect I'm trying to achieve here. I think someone said something about a list of models back there, but it certainly wasn't me. For instance, cylinder and flatbed are maybe two TYPES of machines just like vans and trucks are two TYPES of cars.

I make what I need when I need it, and I make it right the first time so I don't have to do it a second time. That's why I can't tell you what I'm making. There's nothing on the bench right now, and the leather related things that are going to be on the bench down the road are all over the map. If I lose my wallet, I'll make a wallet. I have an old 40s-vintage office chair that I intend to reupholster after I fabricate up a few parts. I make tools all the time, and leather is generally what I use to store them in. There is no thing I do when it comes to leather, it's purely a supporting role at this point, but I'm entertaining making it more of a focus in the near future. To mixkmr's guitar analogy, I've been playing for 20 some odd years, I used to work in a music store selling and repairing guitars, I used to teach people to play guitar, I taught myself luthiery, and have taught classes on luthiery. When I was selling guitars, people would come in all the time to buy a guitar for their kid. I could have just handed them whatever cheapo, and they'd have been happy since they only spent whatever minimum, but I'd only see the kid for lessons maybe twice. Instead, I would ask what the kid listened to (this is where everyone's head is), and if they were into something like death metal, I'd sell them a starter electric instead. I knew that different types and styles of instruments were used to make different kinds of music (this is where my head is), and I used that information to explain why the parent would be more likely to have a guitar playing child in a year versus a gig bag in a closet. In an analogy that should be more relatable to more people: say I want a car, and I'm trying to figure out how to shop for the best car for my current and possible future needs. There are a number of different things to consider, and some of them have a greater impact than others. Vans are best at carrying lots of people, and if you take out the seats they can carry a lot of stuff AND protect it from the elements and light fingers. Trucks are best at carrying lots of things, more than vans, but it's exposed and you're not going to be able to carry too many people. If all that matters is getting from point A to point B, then just about anything will do, but it's worth considering secondary characteristics like fuel economy or comfort. More cylinders typically get you more power, but often at the cost of fuel economy. V8s are about all you usually see, make great power (usually at low RPM), but aren't typically all that great at the pump. V10s exist, but they're pretty special cases and a little flawed. V12s are a bit more common and are great for a lot of reasons, but they're really expensive. Conversely, fewer cylinders CAN save you gas, but you make less power, less torque, and the engines are often pretty crude. Six cylinders are a common middle ground, but that can be inline or V. Inline sixes are naturally balanced, super smooth, and can get really good torque at low RPM OR power at high RPM, but not both without forced induction. V-6s aren't really good at anything save having more than four and fewer than eight cylinders, and are really just an exercise in packaging and marketing and not really worth the trouble unless it's just the only option. Seat heaters are nice to have if it gets very cold, but not at all necessary. AC is also just a nice to have, but may be so nice as to be considered necessary. Infotainment systems are in everything these days, but they tend to kind of suck and are more frustrating than not; don't buy a car for the infotainment system. Cupholders are a thing. Power seats, leather seats, vinyl seats, seat bolsters, air bags... Etc. If someone could simply give a brief overview of sewing machines in the same manner, that's all I'm looking for. I'm sure pages could be written, but pick a topic (i.e. engines) and shoot. Maybe something good can happen... If it becomes clear there's no help to be had here, I'll have to call a dealer who may or may not have what I actually need and may or may not simply try to sell me whatever they have on hand.

I think mixmkr might have me better pegged. I'm not trying to figure out which sewing machine I should get, I'm trying to figure out how to figure out what sewing machine I should get. It's an extra level of abstraction as we say in software engineering. The fish comment was in reference to the give a fish/teach to fish saying; I know just about nothing about actual fishing. Another way to look at it might be through the saying, "If the only tool you have is a hammer, every problem is a nail." The tools we have tend to dictate what projects we tackle and how. If all you have is a tube of superglue, you're probably not going to try to weld up an engine hoist, and if you were so bold as to try you'd not do a very good job. I don't do any particular thing with any regularity. Leatherwork, for me, is a supporting role in a much larger skillset. I do it because I can, it's fun, and it gives me another level of control over material and process. It is not often its own end. Knowing how to know what machines are good for what and why will hopefully guide me toward the best hammer for the wide variety of nails I'm likely to encounter.

Experience is necessary for the qualitative aspects of a thing. In this instance, the qualitative aspects are things like the actual act of sewing, some design of a given feature over another (i.e. servo versus clutch motor), or, lacking access to things like manufacturing tolerances or metallurgy, the quality of one make or vintage over another. Things like foot clearance, SPI, RPM, needle and thread sizes, inches of meterial, and throat depth are purely quantitative. There are numbers and units. Similarly, features like cylinder arm/flatbed, servo/clutch motor, walking foot/bottom feed/etc. are all binary characteristics that are similarly quantitative. There are qualitative aspects to each of the binary feature sets to be sure, but that's a broad enough brush and a specific enough target that it should be fairly easy to communicate in a broad sense. It's a big complex subject matter, and I'm approaching it from a (whatever side of the brain is associated with math and numbers versus language and aesthetics) brained perspective where the prevailing tendency is (the other side of the brain). The thing about committees and such is not me; someone was poking fun at my spreadsheet comment. This is for my own personal shop. I am the board and sole executor. I guess I might try to justify something to my wife, but it'll ultimately just be me justifying it to myself using her as a sounding board. I'm just an engineer. The idea of buying tens of thousands of dollars worth of machines, and all the time wasted and frustration spent using the wrong machines over that time is something I've learned to avoid through the act of buying tens of thousands of dollars worth of machines and time wasted, etc. This community exists for learning, and I'm attempting to do so. Once I feel I have enough of a base to be conversant, I'll likely call a specialist/dealer/manufacturer to get to the deeper and more technical aspects.

Could you please define or elaborate on the following: "...basically one level on top..." I think this is the same as "any shapes below the top surface, or vertical curves, (etc.)...", but it's not immediately clear what you mean in isolation. "...not very tough to penetrate..." What would be considered tough or not tough in this context? "...safe vertical working range..." "...take-up parts..." Looking at things from a strength perspective is sort of my go-to. If money were no object, that would simply lead to the biggest mamajamma extant. I learned last night in chat that machines can have a lower limit to the thickness thread they can handle. A Campbell-Randall awl machine is probably too heavy duty (but look at that gorgeous exposed mechanism!); it states a thread capacity of 3-7 cord and/or 138-415. #138 seems to be a decent middle ground, but lighter thread is not at all an unlikely scenario. I completely don't understand the cord system... That seems to be specific to the actual fiber of the thread...

I wouldn't say I'm withholding the parameter so much as avoiding a rabbithole. The parameter is not pertinent to the design since the design is not for me to pick a sewing machine for what I'm doing right now but to learn how to compare sewing machines so that I can make my own informed decision with a more complete dataset than can (or probably should) be conveyed via text in a forum post. Said another way, I don't want a fish; I want the pole. I don't want to be told what machine will work best for such and such a project or group of projects, I want to be told how to choose what machines are good for what types of projects, how, why, and the obverse. From what I can tell so far, thickness seems to be the single biggest factor, but it seems that generally with a thicker work capacity comes thicker thread. So it's not just a matter of the thickest capacity one can afford, but the thickest capacity that allows for the use of the widest range of thread. If working with finer thread (I can't think of a scenario wherein finer thread would be combined with thicker pieces), you need a smaller machine and vice versa. In what seems on the surface a more straightforward case, a cylinder machine can easily be fitted with a bed to make it a flatbed machine, so there's really no reason to bother with a flatbed machine. Or is there? The ability to reverse into the same holes seems like a genuine positive, but it seems to me that, given the way the machines work, an inability to do so is indicative of excessive wear or poor manufacturing tolerances. There could be some nuance to some particular feed mechanism that might not be as positive as others, but I feel that a quality machine should have no issues here. There's something of a tribal knowledge about sewing machines and leather here, and I'm trying to tease it out into something that can be referred to passively instead of running to ask the village elder or slogging through years and years of expense and experience. Wizcrafts's sticky is very informative. I read it front to back twice, and feel I know a good deal about feed mechanism, clutch versus servo motors, and about not buying into eBay marketing hype. But I didn't leave able to go and compare machines across manufacturers and make an informed decision. Similarly, I read through countless "I want to do X, what machine should I buy?" threads, and feel none the wiser.