Wizcrafts

Cotton and soft polyester/polycore garment threads have no correspondence to the bonded nylon or bonded polyester thread used to sew leather. However, a number 8 cotton thread would be used for buttons, or decorative topstitching. It requires a #25 or 26 needle. This type of thread is sometimes used to sew Chinese leather coats. I have had to replace zippers on coats sewn with this thread. It looks about the same diameter as #277, but is way softer and has less tensile strength than even #138 bonded thread. Most walking foot machines using system 137x16 and 135x17 needles only take up to a #25 needle, which passes #277 thread. Very few of these machines are capable of tensioning this size of thread, or holding down the leather during sewing. In my experience, #207 is about the thickest bonded thread I can use in my walking foot machine (which has large M style bobbins and two pressure springs for the two feet). What do you intend to sew with this machine? It is probably capable of sewing a maximum of 3/8 inch of compressed "material." That could include soft to medium temper leather, but probably nothing very hard, at 3/8 inch. It would do not too badly at 1/4 inch, using #207 thread top and bottom and a #24 leather point needle. You would need to crank the pressure screws all the way down to keep the leather from lifting with the needle.

I have an actual roller foot conversion set on my 31-15. It consists of a 3/4 inch diameter, flip-up rolling wheel presser foot, a single row feed dog the fits under the roller and a throat plate made to fit that feed dog. This set works together as a unit and feeds excellently. If you have a flat presser foot that contains little rollers on the bottom, that feeder is no good for it. In that case you should keep the original feed dog, or move up to a heavy duty set. This provides the best drive for the presser foot you are using.

What's goin on here?

I also have the swing-away guide shown in a picture posted by Photoshutter. Unfortunately, the first time I tightened the thumb-nut down hard, the threaded screw twisted loose in the steel bracket. I had to have it brazed back onto the bracket and this caused other problems with it. I still use the brazed, sanded and filed swing-away bracket with both the original flat guide and a roller guide. I am now able to crank the nut down hard enough to keep the roller guide from moving with the material.

Let me know if any of my advice helps solve the problem.

I bought an edge guide on eBay a couple of years ago, from one of the regular industrial sewing dealers. It has three different edge guides that you can rotate into position. You secure it with thumb screws that I believe were provided with it. Look at you bobbin case on the right side and see if it has one or more tapped holes. If so, and if they are anywhere near being inline with the needle bar, and within about 2 inches of it, this type of guide may work for you. If the supplied thumbscrews are loose, you can buy larger ones. I also bought a sliding roller edge guide, bot it tends to get pushed backward, because my mounting holes are nowhere near the center of the bed. In reality, every industrial sewing machine shop sells edge guides and will modify one to fit your machine. I do shop at Toledo Industrial Sewing Machines for a lot of my parts and accessories (and my big stitcher) and am very satisfied with Bob Kovar's prices and fast delivery. But, sometimes, when I have a few spare bucks in PayPal, I'll make an impulse buy on eBay, from one of the Russian dealers.

Insert the bobbin so it feeds backwards to the slot in the case, or replace the bobbin tension spring. Also, make certain that the bobbin thread is actually passing under the tension spring on the way out of the case. Use the smallest needle that allows the top thread to feed. That might be a #21 for your #138 thread. Tighter holes make for tighter knots and this may alleviate the problem.

I like that!

Bell knife skivers have a steep learning curve. You will ruin a lot of leather before you get it right. Once dialed in, they can do tricks. As for special attachments, that would be specific to a particular brand, or style of machine. Don't ASSume that a foot for one machine will fit the machine you buy, unless it is mentioned in the copy of the ad. Until you actually stand in front of a bell knife skiver and work with it, nothing anybody tells you will have any material bearing on your results. They are a beast unto themselves. Once a user becomes fine-tuned to their skiver, magic can be made to happen. Until then, a lot of leather gets chewed up.

Bell knifes are round across the cutting blade. By nature, they produce a tapered skive, not a straight one. You are going to have to deal with the difference in curvature between the top guide and the blade if you try to produce a flat, wide skive. While you can make multiple passes skiving different areas of the leather, it is not the same as cranking the leather through a flat blade skiver. That said, I have had success skiving wide pieces of veg-tan leather by carefully playing with the positions of the top guide and knife edge. I used to spin the leather around over the blade, until it just passed through with no further material getting skived. The above is more successful on serrated drive cones, rather than conical stones. The edge beveler I referred to is a hand pulled device that has cutting blades on both sides, on 45 degree angles.

Maybe we aren't referring to the same types of equipment. When I say splitter, I am thinking about a bolt on table top splitter, like the Osborne, Heritage, Tandy variety. You mentioned wanting to make belts and a pull splitter can be had for $275 to $400, depending on the width, brand and quality of construction. If you car to pay about $500 - $600, you can get a pull splitter that also does lap-skives on belts. Blades are usually either 4.75 or 6 inches wide. Hand cranked splitters typically go for $800 and up. Motorized belt splitters will be more efficient, but can cost upwards of $1200 or more to get one with a 12 inch blade. To skive edges of belts, or chap leather, you need a bell knife driven skiver machine. These sell for $1200 to $3300, depending on brand, quality, capacity and drive system. I know that most or all of our sewing machine dealers (advertisers) also carry splitters and skivers.

Splitter Skiver Riveter Hand arbor press Edge beveler Edge dyer Strap cutter

Another tip is when you wind a bobbin on the winder, always cut off the starting thread that sticks out as close to the hole as possible. A tiny amount of thread sticking out can affect the position of the knots as it rotates. This is especially so if the thread stub is on the inside, where the ejector spring resides.

I find that there is a bit of a balancing act you need to acquire to get the tensions in the ballpark. Once there, adjustments for new thread, or different thicknesses can be made by twiddling a knob. Let's proceed with a setup using #277 thread, top and bottom, with a #25 needle, sewing 1/4 inch of veg-tan leather. Adjust the bobbin tension for a noticeable, but smooth pull, directly out of the bobbin case spring. Make sure that the bobbin is inserted so it feeds backwards, making a sharp turn off the bobbin, into the thread slot, then under the spring and out. Note, there is a tiny screw inside a hole on the case. That is a set screw that locks the tension screw into position. Good, bad, or ugly, you have to either use it, or lose it. To change the bobbin tension, loosen that little hidden screw, then turn the bobbin spring screw in or out to increase or decrease the drag. Tighten down the set screw when you are happy with the bobbin tension. With the needle threaded, rotate the hand wheel and pull up the bobbin thread. Grab it and give it a tug. Is the tension about the same as with the thread feeding directly out of the case? It should be close to the same, but not jammed. Next, go over the top thread path, from the spool to the needle. The thread should feed straight up off the spool, through the hole or guide on the upper bar, then on to the post on top of the machine. If the thread is too springy it can wrap around the top bar and cause the top thread to have way too much tension. It may even break the thread, or the needle, if it gets totally jammed from a wrap-around on top. I sometimes place a funnel over black thread to keep it from looping over thread guides on the thread stand. If your machine doesn't have a lube pot on top, the top thread must be wrapped around the top post at least one time (in a hole, around the post and through another hole, then out to the top thread tension disks). Failure to do this can allow springy thread to lift up in the upper disks, losing their normal, or all of their top tension. The back pressure from thread wrapping around the top post should keep the thread deep inside the top tension disks. Feed the thread through the thread guide in front of the upper disks, then up and around the disks, snapping it all the way into them. Take the thread down to the lower disks and feed it through the thread guide, then backwards around the disk, 1.5 times. On the second revolution, feed the thread back up through the same guide hole, then to the right, through the movable thread check spring hole. From the check spring, feed it up, through the take-up lever eye, then down, through the snap spring guide plate, then down through the steel guide loop, then through the hole in the bottom of the needle bar. Finally, thread the needle from left to right. Raise the presser foot by the foot lift pedal on the right on the floor board of the pedestal. If set up correctly, this should cause a lever to go between the top tension disks, separating them and releasing most of the top tension. At this point, if you pull down on the top thread that feeds down from those top disks, it should feed with very little pressure from the separated disks (mostly from being wrapped around the top post holes). If you have too much tension screw adjustment, those disks may not release enough, or at all. If this is the case, back off the top disk tension thumb-nut adjuster until you can pull the thread easily. Next, test the tension on the secondary tension disk assembly. Can you still pull the thread around them on the way up to the take-up lever. If not, back off the adjuster nut until you can pull the thread around that adjuster, with just a little tension. Now let go of the presser foot lift pedal. The top tension disks should have closed on the thread, putting pressure on it. Try sewing some leather and see where the knots are. If on top, back off the top tension adjuster, and/or the secondary adjuster. If the knots are on the bottom, either back off the bobbin case tension spring, or add some more top tension (from the upper tensioner). Once the knots are anywhere inside the leather, you can fine tune the position of them using the lower tensioner adjustment. Sometimes, it becomes necessary to add a lot of bobbin tension to balance the knots. This usually occurs with heavy, or springy black thread. Black thread has a lot more dye in it than any other color. This makes the thread tougher to balance than white, beige, or brown thread. There are times when your eye won't see that the top thread has erroneously gotten wrapped back around the secondary tensioner on its way to the thread guide below the take-up lever. This happens more often that you can imagine. When this happens you get loops on top, or broken needles, or frayed top thread. I have even filigreed heavy leather when the top thread got stuck around the second tensioner assembly. BTW: A #25 leather point type 794 needle is correct for #277 thread, top and bottom. But, if the leather is very soft, like draft harness leather, the hole might be too big to properly position the knots. Try moving down to a #24 needle and see if that helps. Bottom line: As long as the top thread is not jamming, or getting wrapped around something it isn't meant to go around, and the bobbin thread is not jammed, nor out of its tension spring completely, you should be able to get consistent stitch knot placement in the range of thicknesses you thread is best suited to. If you can't balance the knots properly, either the thread is jammed, or has come out of its proper tension disk or spring placement.

If you can sew your projects on a flat bed machine, a beefed up walking foot machine should handle either 3/8 of medium, or 7/16 inches of soft temper leather. The Juki 1508NH has a huge bobbin and high lifting feet. It is equipped with the Pfaff needle system 190, which is 3/16 inch longer than the standard 135x(16/17). Material is also cut out in the back of the head to allow the feet to alternate at these heights, without hitting the opening on the back. A new Juki LU-1508NH sells for approximately $2600. Check with our dealers and see what kind of deal they might be able to offer you. For the same money you could buy a short cylinder arm Cowboy CB3500 (441 clone), with a flat table attachment. The machine could be setup to ensure that it sews with thinner thread that you want to use in your wallets, up to #346 used in thick holsters and such. The bobbins are huge and this machine can do it all, from about 6 ounces, up to 7/8 inches. I have the longer arm version and it handles everything from #92 up to #346 thread that I have on hand. I use it to hem leather and denim cuffs, sew chaps, sew belts, assemble holsters and ammo pouches, saddlebags and motorcycle seats. I even use mine to sew in new zippers onto jackets, chaps, etc.

Hmmm. So many requests for features and such a wide range of leather to be sewn. This may call for something out of the usual and ordinary. Let's see what you are asking for: Leather capable sewing machine that leaves no marks Thicknesses ranging from wallets (1/8"?), up to 1/2 inch Thread cutter Bobbin changes with needle down Forward and reverse straight stitch Easy to control motor with wide range at bottom end Your first request calls for a machine that has no teeth on the top of bottom. This can be done with most compound feed machines. However, all but the 441 clones have teeth on the feed dogs. This means you might have to fill in the gaps between teeth in the feed dog with rubber, dipping compound, or brazed in bronze, etc. The second requirement leaves out 99.5% of all currently produced industrial sewing machines. Most walking foor machines max out at 3/8 inches under the presser feet. The remaining 1/2% is filled by the Juki LU-1508NH (or clones), which sew about 7/16 inch, the Juki TSC 441 (or clones; e.g: Cowboy, Cobra, Techsew 441 types), which sew 3/4+ inches, and the Cowboy CB2500 and GA5-1R machines, which sew 7/16 inches. Also, some Adler and Pfaff machines and some specialized Chinese and Japanese machines (Cowboy, Cobra, Techsew, Highlead, etc) have over 1/2 inch capabilities. Machines set up for sewing 1/2 inch or more tend to not have thin needles for thin threads available. This limits you to sewing with #138 or larger on many high lift machines. Others accept small needles, but often require adjustments or parts replacements to effectively sew with thinner thread. A dealer may be able to adapt a thread cutter to the presser lift lever for you. Contact our dealers and ask them about this. It will not be trivial and will cost $$$. The next item, bobbins that can be replaced with the needle down in the material, only applies to vertical axis shuttle machines. Horizontal axis shuttles, like those used in the 441 machines and all Singer 15 and 31 class machines, oscillate along a horizontal shaft axis. You will probably have to remove the needle from the work to change bobbins. I haven't tried doing a bobbin reload with the needle down at all. There will be top thread wrapped around the shuttle and bobbin case until the needle is fully raised. Opening the bobbin case may jam that thread. I'll try it tomorrow and let you know if is doable. Most leather stitchers have a single lever that goes forward or reverse, depending on the position. Others use a stitch length dial and a separate reverse lever that you hit with your right palm. My motors sew very slowly, until I press down on the floor pedals. Not every motor is so easy to control. Some have to be modified with light baffles to get any usable low speed control at all.

A walking foot machine, with triple feed. It cound be a flat bed model, but a cylinder arm allows you to sew circular portions over the end of the arm, in a natural curve. I use my Cowboy CB4500 to sew seats. I change the thread to #138, top and bottom and use a #22 or #23 needle.

That is the model my buddy had and sold for a couple hundred bucks. The feet had aggressive teeth on the bottom. It was a double feed machine, with the outside foot driven in sync with the feed dog on the bottom. The inside foot and needle bar just move vertically, in one position. These are upholstery grade machines and are also great for feeding denim and vinyl, or chap leather.

The Singer patchers are a perfect machine for sewing patches onto Biker's vests and jackets, especially onto sleeves. They are also good for repairing shoe uppers that have come unsewn with use. You can do all kinds of repairs and even install new zippers on a patcher. You are pretty much limited to using #69 or #92 bonded thread. The bobbins are tiny. The feed is top only, via teeth under the presser foot. The maximum thickness it can sew is about 1/4 inch of soft to medium temper leather.

I forgot that this topic was about your Pfaff machine, not the 31-15. Is your Pfaff supposed to use system 134, or 134-35 needles? There is a difference in length and geometry. I can use some 134 LR needles (from my previous Pfaff industrial machine) in the Singer 31-15. However, it cannot use 134-35 unless I raise the needle bar. Check your manual and make sure you use the correct Pfaff needle system. This might mean retiming the hook, or moving the needle bar. I have experienced movement of my 31-15's needle bar. I used that fact to change the set screw to a new one that I could really tighten down. The original was 96 years old and worn. As for modding your shuttle for #207 thread; opening up the clearances will allow #207 to pass around the bobbin case and the top tab on the case, then past the tapered end of the shuttle driver. But, the extra slack may mean that thinner thread skips at various speeds, but especially when sewing single stitches (stop/start), or hand-wheeling. The timing of the hook and spacing from the side of the needle (for #207) may render it ineffective for say #69 thread. If you do anything to the shuttle driver, like bending it, or any other parts on the shuttle assembly, have a spare on hand just in case.

Perhaps these folks have newer models of the 31-15 than mine. It was built in 1916, according to the serial number. It won't even sew with #138, much less 207 thread. When I tried to open up the clearance between the shuttle and shuttle driver, it began skipping stitches. The timing became erratic at best and the machine was not trustworthy under that configuration. Your mileage may vary. Another thing that is weird about the 31-15 machines has to do with variations in the angle of the bobbin case mounting tabs and the opening in the tab plate. I had to bend one tab in and the other out to keep the bobbin cases from spinning around. Again, your mileage may vary. The needle bar in my 31-15 does not accept #23 needles. It uses a thin stem needle meant for tailoring machines (e.g. 96k40), which line up dead center in the little hole in the throat plate. Anything else would hit the throat plate with the slightest deflection. I cannot use other needle systems without a lot of difficulty (been there, tried that). The biggest needle my machine uses without trouble is a #21. Finally, these 31-15s use a standard (small) bobbin. If you load it with #207 thread it may sew two belts. Aside from the difficulties, I like my 31-15 for tailoring, hemming clothing and lightweight leather items. I even use it to sew patches onto vests, right through the lining. I have converted my 31-15 into a roller foot machine, for better feeding of garment leather.

A buddy of mine had a Rex 280 something that had teeth on the presser feet and feed dog. It marked up the leather pretty badly, but fed like a SOAB.

Bonded nylon.

#207 thread in a Singer 31-15? I am barely able to get #92 thread around the bobbin case and shuttle (it snaps noticeably as it passes the top of the bobbin case). The slack in the shuttle driver would have to be tremendous to pass #207 thread. This would make for unreliable timing as the position of the hook varied with rotational speed and top thread tension changes.

Trox; I run all of my top thread through a lube pot containing liquid silicon. It helps maintain top thread tension, lubricates the inside of the holes and cools the needle. The silicon is clear and does not appear to discolor natural veg-tan leather at all. Ditto for the clear oil I use to lubricate the machine.