Wizcrafts

Please post a good closeup photo, or two, of your round knife. Nothing much sells here without clear photos. Also let folks know your location and what currency you accept and methods of payment. Items shipped to the US from Asia may be subject to import duty.

I use a #24 needle when I sew with #207 (210) thread. But, if you only have the 207 on top, a #23 will do. Using the bigger needle makes it easier for the take-up lever to do its thing. This means you can reduce the tensions and still balance the knots. Less top tension usually means less breaking of the thread. Frankly, I would use #138 thread when sewing 8 ounces of leather. It is strong enough for that thickness and can be sewn with a #22 needle. As for the appearance of the holes, try using S point needles. Bob Kovar just got some in stock in system 135x16. The typical leather points used in the walking foot system are diamond/triangle point which poke a bigger hole.

You should be using either a #22 (140) or #23 (160) round point needle with #138 bonded thread in canvas. The #23 pokes a bigger hole and makes it easier to pull the knots up. (Leather point needles are only for use in leather, not canvas, cloth or webbing.) You absolutely should be able to loosen or tighten the bobbin spring tension. If the knots are always on the bottom and you are using a #22 or 23 needle, loosen the bobbin tension spring action by backing off the screw nearest the hole where the thread comes out of the bobbin case. Make sure there is sufficient top tension to pull the bottom thread up on the upstroke. It takes more top pressure than bobbin pressure to pull the knots up. Make sure there is enough foot pressure to keep the material from lifting with the needle.

I timed one of those a month or so ago and set the needle to the center to time the hook. Then I verified that it still picked off the thread at the extremes of the zig zag throw.

The table should be 20" x 48", with steel legs and a (probably clutch) motor underneath. The head sits in a cutout in the table and has two tilt clamps on the back, for tilting it back to remove the vbelt. With the belt off the 50+ pound head can be lifted off the table. The top of the table will probably have a thread stand and flex lamp and a bobbin winder. If you need to remove the thread stand, you will need a flat blade screwdriver for sure and possibly a Philips driver. The motor will be bolted onto the table with nuts that may have SAE or Metric heads, ranging from 1/2" to 5/8", or 12mm to 18mm. Bring open end wrenches. The motor will have wiring clamped to the table bottom, leading to a switch box that will need to be unscrewed and removed.

The reverse lever on an LU-563 floats the feed mechanism towards you, shortening the stitch length until it reverses completely.

As Tom said, slightly raising the feet lets you cheat the stitch length. The smooth top feed dog on the Cowboy/Cobra/Techsew 441 machines makes it easier to do this.

According to ISMACS, her machine is one of 2000 built on September 6, 1939.

Use a silver or gold gel ink pen (from Hobby Lobby, etc) to place a dot at the exact point where the needle has to go at the tip. As you approach the turn slow down, hand wheel the machine and stretch or compress the stitch length to force the needle to hit that point. It will cover the ink if done correctly. With the needle buried in the point hole, wheel just enough to raise the needle about 1/4 inch. Raise the feet just enough to clear the leather, with the floor lifter pedal. Turn the work and continue sewing. I assume you are using an edge guide, so I didn't mention it.

Try reducing the tension or travel of the check spring. Consult your manual for how to do this, or Google it.

I will address your concerns about the CB4500, as I own one. The CB4500 has the capability of sewing from about 6 ounces (with thin #92 thread) up to about 56 ounces (~ 7/8 inch). Both extremes require some tweaking. I already wrote a blog article explaining how to dumb down a Cowboy CB4500 to sew thin material with thin thread. The other end is not really explained yet. I will tell you the basic path I took to sew a holster that was just shy of an inch thick. The alternating lift of the inside and outside feet is usually set fairly high to clear new layers of 8-10 ounce leather. The higher the lift of the feet, the more you lose at the very top end of sewing capacity. So, my first step was to reduce the lift to the machine's minimum setting (done on the back). This resulted in an alternating lift of under 1/8 inch. I used the standard low throat plate and feed dog, but I lowered the fully raised position of the teeth to just be level with the top of the throat plate. I used the standard double toe outside foot and the movable sliding edge guide to set the distance to the needle at a 1/4 inch from the beveled edge. I replaced my standard pressure spring with a heavier duty spring Bob Kovar mailed to me. The standard spring was a tad lacking for such a thick stack of veg-tan leather. I understand that the CB4500s now ship with the heavier spring if you request it up front. That spring got cranked almost all the way down to keep the feet from lifting with the big needle and thread payload. I ordered diamond point needles in size 25 and used #277 thread. All that remained was balancing the height of the knots and the stitch length. This combination allowed me to sew a 7/8 inch+ holster at 5 to the inch without cutting the threads as I crossed over them to lock them in. Also, the diamond point holes caused the thread to sit more on the surface for a better appearance, unlike the S points that submerge the edges of the thread and shorten the stitch length visually. Here is that holster.

Hightex Special Sewing Machine (China) owns the Hightex and Cowboy brand names. Cowboy USA is their preferred brand sold in the USA. The company's website is www.cowboysew.com

I have a blue body Singer 29k172 long arm machine that says Made In Japan on the tag on the back. I almost bought a Singer 22U with a blue body that also said it was made in Japan. It might be that the Japanese built Singers had blue bodies to distinguish them from those made in the USA or UK.

I bought a slotted inner foot and a short left toe presser foot set for my Singer 139w109 walking foot machine from Leather Machines Company (aka: Cobra).

I am on my 3rd skiver right now. It is a Fortuna, bottom feed only, and works well, if I don't mess up the clearances. The most important clearance is between the right side of the foot and the blade. Of course, the blade needs to be sharp to be effective and be deburred. Choosing the best feeder makes a big difference in the quality of the feeding of the material. My machine came with both a serrated steel and an abrasive stone wheel. The steel wheel is best used with veg-tan leather. The stone wheel tends to slip under veg-tan, but has positive feed for garment and chrome tanned leather and vinyl. I keep the blade close to the foot on soft leathers and farther away for veg. Keep the machine oiled. I ended up putting a servo motor under my skiver table. As long as the blade is really sharp, it cuts at slow speeds as well as fast rotations. Cutting slowly leads to better flow control and less eating of the leather.

The machine is a chainstitch post machine using a needle and awl system with a jump foot. It is used to sew golf bags, rifle bags and similar objects. It should not be used where the bottom thread is visible or exposed to chafing. Because it produces a looped chainstitch, there is no bobbin used. The chain needs to be secured by sewing across it, or by using wax on the thread to lock the thread in place. Most companies using these run either hot or liquid wax in the waxpot. It works best with linen thread, preferably, Barbour's Irish linen thread (over $50 a pound).

Toledo Industrial Sewing Machines has a videos page that has a video showing how to thread a CB4500 (and related models) and others demonstrating how to sew different items on it. The links load the selected video into a frame on the page.

I own a first generation Singer 31-15 from the early 1920s and I can tell you without hesitation that is cannot handle #138 thread in its shuttle. In fact, I am limited to a max of #69 thread. It sews about 1/4 inch of compressed soft material and is best used as a tailoring and alterations machine for cloth and linings. The take-up links and needlebar mounts are not strong enough to withstand the pounding that sewing veg-tan leather would place on them. A much later generation of the 31-15 can probably sew with #138 thread. I know some folks who use later builds to sew chaps and shoe uppers.

This section of the LW.N forum is for discussing leather sewing machine capabilities and their suitability for particular types of projects. Please visit our Market Place section of the forum where there is a sub-section for buying and selling new/rebuilt and old sewing machines. Most posted on Leatherworker.net are leather sewing machines with various capabilities.

Keep an eye on the thread as it unwinds from the spool. Follow the thread as it makes its way to the top tensioner disks. Watch for any sign of binding as the thread comes of the spool. Watch out for twisting that forms loops and knots in the top thread. Either of these things will increase the top tension temporarily, causing the knots to move up.

This machine has a dual, top and bottom feed walking foot drive. It is meant to forcibly pull material from the top and bottom. It does this by means of the aggressive teeth on the feet and feed dog. The needle and inside foot have a static position and only move up and down. The presser foot is operated by the crank on the back left end of the head and is synchronized to the feed dogs. Machines like this can typically handle up to #138 bonded thread and a #23 needle. The bobbin and bobbin case are on the left end of the machine (known as a horizontal axis bobbin). A photo of that end tilted back would expose the bobbin case and we might be able to discern if it uses standard capacity or oversize M style bobbins. Because this type of machine has teeth on the top and bottom, they are best not used with any veg-tan leather that would memorize the tooth marks. They will even leave some tooth marks in chrome tan leather. However, this feed is great for webbing!

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If you don't get any recommendations for an industrial sewing machine repairer in your neck of the woods, and you have a hankerin' to try to fix it yourself, take this topic over to our Leather Sewing Machines forum and start a new topic. We have lots of experienced members and several dealers who frequent that part of LWN. Don't pursue a hands-on repair in this forum. Every reply will need to be approved by a moderator before it goes live and it can become frustrating.

TomG; Did you know that there is a type of heavy duty sewing machine that can handle up to #346 thread, sewing up to 7/16 inch of leather, that sells for about one thousand dollars, assembled on a table? This type of machine could handle those extra heavy thread jobs at a reasonable cost. The main thing to be aware of is that it is a bottom feeder only.

There are machines that are built to do light, medium, heavy and extra heavy sewing. Each step up is accompanied by more beefed up take-up parts, springs, tensioners and shuttles. However it is configured, the shuttle must have sufficient clearance between the hook and needle and any other obstructions to clear the largest thread it is expected to sew with. There has to be clearance over and under the bobbin case to allow the top thread to go around it without binding. The heavier duty machines may use two screws to hold the needle bar in place. When all is said and done, your machine is NOT built to clear #207 or heavier thread. There are no tricks I know of or would recommend. The stresses of #207+ thread on the take-up and drive mechanisms are too much for a medium duty sewing machine. If you really need to use #207 and #277 thread, consider a heavy duty machine like the Cowboy CB3200, or an extra heavy duty 441 clone, like the Cowboy CB4500, Cobra Class 4, or Techsew 5100.