Wizcrafts

The dealers who import Cobra and Cowboy branded machines have to pay all manner of shipping, warehousing, brokerage, tariffs and delivery fees before the machines arrive at their warehouses. Once the boxes arrive, when a wooden shipping crate is opened, the dealer spends between 4 and 6 hours de-greasing, assembling, adjusting and setting up the machine to test it. The machine will only be sold if it is fully within its nominal operating parameters. It will ship with a stack of leather under the foot/feet that is within the upper limits of that machine. For the 341/26 machines, that would be a 3/8 inch stack. Demand for these high quality machines, shipped ready to go to work, is high most of the year. I haven't seen any special sales where one brand tries to undercut another brand. Furthermore, they handle service requests personally. They don't have offshore tech support. If you aren't sure that the prices being charged for a new Cobra or Cowboy machine are very reasonable, ask Google about the price for a new equivalent machine with the Adler or Juki label. Make sure you're sitting down...

Try reversing the direction of the bobbin. It may need to go in opposite to the way you already inserted it. I usually insert bobbins so that the thread makes are sharp turn backwards towards the slot leading to the bobbin tension spring. This back force tends to keep the bobbin thread well placed under that spring leading to more reliable stitches.

You might want to define the meaning of the word "salpa" for us old school leather crafters. Since it is a requirement, it will help to mention if you are supplying it and other materials and hardware to your prospective assignees, who will be freelancing to build things for you.

Way back when I was only sewing for about 2 or 3 years, I bought two post bed machines with roller feet off some shoe maker who was going out of business. I used them to sew Marlon Brando style biker caps. I even sewed a Cowboy hat or two, and sewed patches onto ball caps. One day, I counted all of my sewing machines and discovered that I owned 13; a Bakers' Dozen! They included everything from a flat bed tailoring machine to a huge Union Lockstitch machine. That truly was a rabbit hole. Then, I moved and sold all but two machines. I eventually sold the big ULS and went into computer troubleshooting. I finally escaped from the sewing machine rabbit hole! Then, one day, as the computer troubleshooting was winding itself down, I saw a National walking foot machine for sale, cheap, nearby, and bought it. Y'all can guess what happened next... More rabbit pellets.

There is a specialized industrial sewing machine that is perfect for sewing all kinds of hats. It is known as a post, or post bed machine. Some have a flat foot with bottom feed. Some have a roller foot and bottom feed. I have one that is a triple feed walking foot mechanism. A post machine lets the work hang down on all four sides. My Singer 168G101 has a 7 inch tall post. I have used #138 thread in it, although it is happier with #69 and #92. This machine uses the same bobbins as the Singer 111 series machines.

The largest needle commonly available for domestic sewing machines is a #18/110. I once found some #20 needles for an old iron body Singer from yesteryear. Those machines held up much better than the plastic body machines of today. I mentioned this because most so-called Upholstery thread is #69 bonded nylon. This size is normally sewn using a #18 (Metric 110) needle. Leather point needles work best on leather, as opposed to round points. You should be able to get a decent stitch using #69 thread with a #18 needle by balancing the bobbin vs top tension and enough foot pressure to keep the leather from lifting with the ascending needle. But, if you plan to sew leather on a regular basis, buy an iron body walking foot machine that's mounted on a 20 x 48 inch industrial k-legs frame and table and powered by a 3/4 HP servo motor.

The only purpose of a roller foot is to reduce the drag on the top layer of a stack of material that's being pulled on the bottom by feed dogs with teeth. If the material is grabby, a flat presser foot will fight against the feeding and cause uneven stitches. They are often used on machines that are going to sew patterns on shoes and boots, or on machines that sew hats. The roller is adjustable to the left and right. The usual practice is to position the bottom inside edge so it just clears the needle on the up and down stroke. This closeness ensures that the material doesn't lift with the ascending, threaded needle, which would cause skipped stitches. A roller foot gives 100% visibility of the needle in three dimensions. As KGG already mentioned, they are not used on walking foot machines, which have not two, but three bars extending down. They are meant for bottom feed machines that only have one presser foot bar. Walking foot machines already solve the problem of drag with their motion sequence.

These heavy duty harness stitchers usually ship with high thread tension and foot pressure because they are typically used to sew hard, dense leather. You will need to dumb down your machine to sew soft leather. Start by backing off the bobbin tension screw until there is just a slight amount of pull required. Next, back off the top tension to balance the knots. Next, back off the top foot pressure screw on top of the right end of the head. Use just enough force to keep the leather from lifting with the threaded needle and the bobbin thread locked around the needle. This setup won't work as well in dense leather, so try to make a mental note about the initial setup tensions and pressures. Finally, adjust the stitch length a little shorter to minimize the warping of the material.

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.