Wizcrafts

Coincidentally, I had a customer come to my shop yesterday with a dozen webbing straps that I had to sew together in pairs, at the loose ends, with a 3" overlap. I chose #138 yellow bonded polyester thread and used a #23 round point needle. I had to retime/advance the hook to avoid skipped stitches in reverse, and adjust the check spring throw, in addition to increasing the bobbin and decreasing the top tension. All of the tension changes will have to be undone when I have to sew a holster or sheath.

I used to sew Biothane and heavy webbing in a previous location. I found that I had to move up one needle size, and use a diamond or round point needle. Additionally, I had to double the foot pressure to keep it from lifting with the ascending needle. Running the top thread thru liquid silicon will help the knots move up with less friction. It might help if you adjust your check spring to give more slack top thread as it goes around the hook. Try it on a test strip. Thread color also plays a part in all heavy sewing jobs. Black thread is often double-dipped to get total color penetration. This process stiffens the thread more than lighter colors. You can usually feel the difference when you handle the thread to feed it through the guides on thread stand. Straw color is usually much softer than black. That translates into tighter knots being formed. Tighter knots are easier to pull up in dense materials, like Biothane and thick webbing.

What machine make and model are you currently using? What size needle and thread?

@speedybri This sounds like a case of the leather is too dry and dense. Is it the awl or the needle that is getting stuck and lifting the stack of leather? If it's the awl, you may need to oil the leather to soften it a little. Or, run the thread through liquid stitching wax or silicon in the wax pot. If it's the needle, either move down one needle size or move up one awl size. And, add more foot pressure until you figure out the real problem.

I copped a boo at one of my speed reducers that bolts to the table in a box above the motor. It looks like it has a bronze case bearing, but, I'm not sure about that. I bought it about 10 years ago and it may be outdated. I have different reducers on machines in my shop. I will look at them later today and try to remember to report back here. Nonetheless, Bob Kovar, at Toledo Industrial Sewing Machines, sells the most current accessories. So, the newer speed reducers might have roller bearings in all models. Ask him.

Many years ago, I had a Union Lockstitch machine that was made to sew horse tack. The ULS is a needle and awl machine. The needles are barbed like hand sewing needles are. I explored all of the available thread options, then bought needles and awls that would punch the proper size holes for that size of linen thread. In my searches, I found that the thickest linen thread sold in the USA at that point in time was Barbour's Irish Linen in 8 cords. This is equivalent to .828 mm diameter. It called for a gigantic needle, size 30, which nobody had in stock. The largest needle I could get was a #250. It was able to hook and sew with 6 cord linen thread. I later discovered that these thicker sizes of thread were meant for the shoe repair trade, not saddlers. Some shoe sole sewing machines were apparently capable of handling up to 10 cord linen thread, which is about 1 mm diameter. They are specialized machines that can weigh 500 pounds or more. I would recommend that the OP searches for an old time shoe repair shop that uses old sole stitchers and see if they can sew his or her projects for a nominal fee.

@MelissaViarengo Looking at the pictures of your machine, it looks like the teeth have been filed almost entirely flat on the bottom of the foot. The entire feed is done by the teeth digging into the material. If those teeth are blunt, or missing, the foot cannot pull the material back to form stitch length. The teeth on the foot should be sharp to the touch. You can find replacement 29k presser feet on ebay in Italy. While you await your replacement presser foot, try adding some thin rubber or clear carburetor tubing to the feet. 1/8 inch inside diameter should fit on the legs. This may have enough grip to pull the work to form stitches. Add more spring pressure too.

I have an old Singer 139w109 that has a 20 inch flat bed from the needle to the body, plus it has a compound feed walking foot mechanism. It was converted to take Juki U size bobbins. The wheel is on the back, but that isn't a problem. It is easily reached. This type of machine is based on the ubiquitous Singer 111 series machines. It can sew 3/8 inch of material with up to #138 bonded thread. I mostly use it to sew embroidered patches onto biker's vests. That's where the 20 inches of bed space comes in handy.

You'll need to get a proper walking foot machine, then get #18 leatherpoint needles in the "system" that machine uses. For instance, my Singer 111 and 211 machines take system 135x16 leather point, and 135x17 round point needles. I tend to hunt for titanium coated needles because I sew through leather tape or glue on a lot of jobs. Titanium coating helps prevent clogging of the eye of the needle. I also keep Goof Off and a dauber close by to clean the crap off the needles when they do get full of tape residue!

Welcome to Leatherworker.net As you have discovered, the machine you have is inadequate for the work you have on hand. My article that was linked to earlier today should help you understand the type of machine that actually sews leather. Within this basic deinition there are various levels of capacity in the various makes and models available. At the very least, you should look for a compound/triple feed walking foot machine. Early examples are the Singer 111w155 and 156 (has reverse), the older Juki LU-563 and newer models, like the Juki DNU-1541, and some Consew models that have triple feed, like the Consew 206RB-5. These machines can handle up to #138 bonded nylon thread and actually tension it enough to sew over 5/16 inch of leather, depending on its density. They weigh over 70 pounds and need to be fitted onto industrial sewing machine tables that have steel legs. Most tables are 20" x 48". They are usually equipped with powerful clutch or servo motors that drive the heavy steel mechanism through stacks of leather that would destroy a home hobbiest's machine.

As previously mentioned, it is not a walking foot machine. Some of the best known Singer walking foot machines are the slower speed 111w155 and 156 (w/ large balance wheel pulley), as well as the higher speed 211w155 and 156 (w/ small pulley). There are also some older Singer walking foot machines that have whaat's known as a spring foot. These have a foot that simply follows the material as the feed dog pulls it back. They only had bottom feed. A proper walking foot machine has at least dual, if not triple feed.

@MelissaViarengo You have the stitch length adjuster way up high on the foot driving bars. That position gives the shortest stitches. Lower the adjuster by loosening the round thumbscrew. You can set it for its maximum stitch length by raising the foot lift lever and lowering the adjuster, aka regulator all the way until it just touches the top of the raised foot. After lowering the stitch regulator, tighten the lock screw to keep it there. You should be able to get almost 5 stitches per inch in about 5 ounces of shoe upper leather. Anything less indicates excessive wear in the foot driving cam that rides inside the big round ring on the bottom of the head. There is a stud shape sticking out of that cam that rides inside the round ring. When the ring moves down, it pushes on the dtud and that causes the foot to get pushed back to pull the material.

That machine looks very similar to the Consew P-1206RB. It could be the forerunner of the 1206. Maybe the specs on the page will apply to your machine.

I would lower the stitch length gib until it just hits the top of the foot when it is in the manually raised resting position. This is the highest position the foot can reach and the longest stitch length setting possible for this type of machine. With the foot lifted by the lift lever, push and pull on it to see how much slop is in the mechanism. If it has noticeable slack motion, that translates into lost stitch length. The thicker the material, the greater the loss of stitch length no matter how tight or loose the foot drive parts happen to be. Remove the needle for this item! With the foot lifted, rotate the balance wheel towards you from the top. Verify that the foot moves forward then backward. Hold the front of the foot by the legs and see if it still pulls backward under a slight resistance of your hand on it. If it fails to pull back, the feed motion cam is worn beyond viability and must be replaced or rebuilt by someone with welding or soldering skills. Otherwise, move on to the next item. Lower the foot lift lever and check to see if the bottom of the foot is in contact with the throat plate. It must be in contact if it is to sew thin materials. The movable slider on the back takes care of how high the foot lifts as it moves forward to pull the material. If it doesn't go all the way down, something is interfering with its up-down motion. It could have to do with the next item. Make sure you have a decent amount of spring pressure on the foot! Tighten the thumbscrew on the middle of the big spring along the back to add more pressure, and vice-versa. Make sure there are sharp teeth on the foot. Dull feet won't feed most materials, or slick leather. You can hammer or rub out the tooth marks later on. So, make sure that the lowered foot goes all the ways down, then lifts up to the height set by the lifter on the back. Verify that the foot feed motion cam is moving the foot backward as the machine turns over. Know that parts specific to this model (-4) are obsolete. Most people have to find donor machines to strip parts from, or have parts repaired or modified. Pray that the little gears inside the arm are still good!

Please look at the package that the needle came from and let us know the designation on the needle. For instance, a System 794 or 7x4 in Schmetz S Point, or a 4-sided Diamond, or 3-sided Tri point, or an LR or LL twisted wedge point. The first 3 give a straight stitch line, but with a different visual front to back length on top. The last two are made with a left or right twist on the tip of the needle. While the needles can lay the thread differently based on their geometry, the only ones that might try to push the leather sideways are the LL and LR slanted wedges. Personally, I avoid slanted needles. My preferred needles either have a diamond or tri point, or an S point, which is an inline slicing wedge. If you sew a stitch line with each of these two types, using the same stitch length and tensions, The S point stitches will appear closer together and submerged, compared to the diamond shape needles. Then, there's always System 7x3 round point needles that poke a round hole and are made to sew fabric and synthetics, and create a straight stitch line with good visual appearance between the ends of the stitches. Now that the needle geometry has been discussed, there is something mechanical that could cause the strip to move sideways as your sew. That is a misaligned or loose needle bar and inside foot mounting frame. Normally, this frame is installed with a minimum of sideways clearance to keep it sewing straight. If some impact knocks the frame alignment out, it may sew off the center line. Look to see if your machine has an L shaped bracket screwed on at the bottom of the moving frame that contains the needle and inside foot bars. If present, make sure it hasn't loosened or moved to the left and giving too much clearance to the moving frame, which might be called the "rock frame," or such.