Wizcrafts

If your stitch length is set by a rotary dial with detentes, the knob could be a little too loose. The shaking from higher speeds or new layers to overcome might cause the knob to leave the preset position and move one way or the other. Try finding a set screw that secures the knob onto its shaft and see if you can loosen it, push the knob closer to the body, then tighten it again. This may keep the knob and the shaft its on from turning on their own.

My Cowboy CB4500 is very similar to the Adler 205-370 machines. I have a Family Sew 550s servo motor with a 50mm pulley and a 3:1 speed reducer with three pulleys. As an experiment, I tried going directly from the motor to machine and it had a very hard time penetrating a quarter inch of bridle leather, at slow speed, without me manually turning the hand wheel to get it going. Servo motors produce much less torque at slower/startup speeds. Once under way, the motor was able to keep it sewing until I stopped applying power. This gets aggravating if you need both hands on the work from the get-go. Reconnecting the speed reducer restored the full slow speed experience needed to start with both hands on the work. I did own an Adler 204-374 flat bed walking foot machine a few years ago. It had a 3/4 hp, 1725 rpm clutch motor, with a 2" pulley, feeding a 2 pulley speed reducer, feeding the huge pulley on the machine. The top speed was 2.5 stitches per second and it penetrated anything I could fit under the foot. Controlling the clutch was a piece of cake for my foot and it feathered down to 1 stitch every 2 seconds. Just my 2 cents

Catskin; Don't bother extending the check spring travel beyond what's already available. It only needs to keep the thread taut until it meets/penetrates the top of the leather. If you keep the tautness to long the thread loop may not fully form above the eye. The combination of best size needle and check spring travel should be enough. Don't neglect examining the thread for "twistiness" (a brand new Wizicism!). If it is too twisty, loop it around the top post once in the opposite direction, to counteract the twist. Chubby Checker that bad boy!

I should have clarified that a servo motor alone may not be strong enough to power the machine through thick leather without help from the hand wheel. It would definitely have to be a very high wattage motor and have a very small motor pulley. You will need the speed reducer either way.

The clutch motor equipped with a typical 3" diameter pulley, feeding a 2:1 speed reducer should do the trick. Just back off the motor's clutch adjuster bolt for a comfortable amount of free play before the clutch engages. You get the benefit of the free play that most servo motors lack. The 2:1 reducer doubles the torque and reduces the speed to 1/2. With the pedal down, you would convert your 1725 rpm motor to 862 rpm at the output of the reducer. The pulley diameter on the flywheel is probably about 6 inches or more. I would guess that the small reducer pulley to flywheel pulley ratio would be at least 3:1, giving you a top speed of under 5 stitches per second; pedal to the metal. A smaller motor pulley will slow it down even further, possible to as little as 2.5 stitches per second, which you can surely learn to feather down to under 1 stitch per second.

Lengthen the travel of the check spring to its maximum. This is done via the movable stop bracket under the spring, which is mounted onto the bottom tension setup. I use a #24 needle with #207 thread. It produces a good hole for the knots to sit in. Not too loose and not too tight. The needle number is usually embedded near the top of the mounting shaft of the needle.

It is a standard looking straight stitch build. Call Ronny and ask him to send you the heavier feed dog and throat plate set. A couple of spare feed dog and throat plate screws is also a good idea. These tend to fall on the floor when you change feed dogs and are mysteriously squirted of of the Universe, never to be seen again. You may be able to get a larger roller wheel, but it will require raising the presser bar to get a proper fit. I think that more aggressive feeders will do the trick. Then you can play with the foot pressure to even out the stitch lengths. Did you know that thread tension can affect the stitch length? This is especially so when you change thickness. A looser top and bottom tension combination is easier to transport than a heavier combo that fights the feeding action. Just don't loosen it to the point of slack in the top or bottom stitches.

Sometimes, machines driven by cogged belts have the belt installed in a slightly wrong position. It may be off by one cog, advancing or retarding the best timing position. The machine can still be timed by the hook, but the top take-up lever and rotation of the hook are not optimal. This causes the type of thread snap your machine has. You should contact the dealer from whom you purchased the machine before opening up its guts, especially if it is under any kind of warranty. They may be able to offer guidance over the phone, or via a link to a posted video detailing how to retime the top and bottom shafts.

What make and model is the roller foot machine? If it is a flat bed straight stitch machine, what feed dog and throat plate set is installed? They usually come in three levels: fine, medium and course teeth. If you have fine teeth now you might do better with the medium or course set (with matching throat plate). With more tooth driving the bottom, you will get more consistent top stitches with the roller foot. BTW: What diameter roller do you have?

I have my doubts. The 8300N is a very high speed tailoring machine. It uses thin thread, has weak tension springs suited to cotton or polyester garment thread, has a fine tooth 4 row feed dog, and prefers to be run at about 91 stitches per second - to distribute the oil from the sump pump to the ends of the wicks. It will sew about 1/4 inch of cloth, using system DBx1 needles, ending at number 18. The thread handling limit would be no more than B69. Here are the specs I do believe that such a machine "can" sew thin leather, up to about 6 to 8 ounces, as long as it is soft temper, like garment or chap leather. Controlling it would require a servo motor with a pulley smaller than 2 inches. The Family Sew 550s is such a motor and Toledo Industrial Sewing Machines offers them with custom bored small pulleys to slow them down and torque them up for leather sewing. The machine must be run at high speed to distribute the oil. This can be done while winding bobbins, as well as before you start to sew. Just remove the top thread from the take-up lever, raise the presser foot and floor it.

I don not believe that the Tacsew T622 is anything more than a high speed straight stitch (garment) sewing machine. If it has one static presser foot bar in addition to the needle bar, and the needle only moves up and down, it is a straight stitch machine. A walking foot machine has three bars coming down.

A walking foot machine has two interlinked bars containing presser and vibrating feet. The inside foot extends under the needle bar and moves forward and backward and up and down with the needle, in sync with the feed dog. The outer foot moves up and down, securing the work as the feed dog and needle move forward for the next stitch. You either have or don't have a walking foot machine. Domestic (home) sewing machines have screw on attachments that are sometimes called walking foot attachments. They are actually just follow feet to keep layers of cloth from separating under the foot. The feet do not help transport the material and do less than nothing on leather.

A proper sewing operation has more that one machine. I recommend a flat bed upholstery grade walking foot machine, like the Consew 206RB-5, for medium thickness material and thread (up to 3/8" with #138 thread). Then add a heavy harness stitcher for items exceeding 3/8 inch thickness, or requiring thicker thread (#207 - #415) and finally, a flat bed tailoring machine (e.g.; Singer 31-15, 96k40) if you need to sew thin cloth garments or satin linings together. Each type of machine covers a specific range of work for which it is best suited This is a good basic starting setup. Add other special purpose machines as the need arises.

That #5 is a good machine for jobs where you don't see the bottom layer. This includes saddles, seats and webbing. The same machine is available with the designation of Cowboy CB2500 (with or without reverse and roller foot), the Techsew 3650, various brands of the so-called GA5-1, as well as the ancient Singer 45k models, upon which these machines are based. These machines sew up to about 7/16 to 1/2 inch of leather or webbing, with thread sizes 138 through 346, using system 328 needle sizes 23 through 27.

Choose the largest thread that allows you to hide the knots between the layers. It will fall between #277 and 346 for two layers of this ballistic nylon. Actually, 346 is pushing it a bit. Your machine has to be perfectly adjusted to consistently place the knots between the layers. You can calculate the strength per stitch by consulting this needle and thread chart. I suspect that using #277 thread, rated at 44 pounds tensile strength, will do the trick. Just space out the stitches to at least 5 per inch, or about 3/16" spacing on outer edges with less stress, and 4 per inch when sewing across hardware and buckles, or high stress areas. This will avoid weakening those seams due to the proximity of the holes. FYI: Black bonded thread is always stiffer than lighter colors. White thread is typically the softest. Softer thread forms and positions the lockstitch knots more easily and much tighter for a given tension combination. This is why many professional saddlers and holster shops use barbed needle and awl machines and run soft but thick linen thread though a liquid wax pot. Once the wax dries those stitches aren't going anywhere, even if one breaks. Just look at a quality leather shoe or boot sole that is sewn with 6 to 8 cord waxed linen thread if you want proof. Unfortunately, modern closed eye needle machines cannot effectively use waxed linen thread.

What causes skipped stitches? Skipped stitches can be caused by any or a combination of the following defects: Early or late arrival of the hook, above the eye of the ascending needle. Excessive clearance between the gears that drive the shuttle and hook. Insufficient foot pressure that allows the leather to lift with the needle. A burr on the tip of the needle. The needle is too large for the thread. The oversize hole causes a loss of back tension on the loop, causing it to dissolve prematurely. Too much travel and/or tension on the check spring, causing the loop to dissolve prematurely. Overly twisty thread that causes the loop to twist away from the hook. A burr, or other defect at the tip of the hook. Intermittently binding top thread. Intermittently binding bobbin thread.

The bottom line is that the "Cobra" branded sewing machines are imported and distributed by Leather Machine Company, in California. They have banners that appear in the rotation on top of the pages on all our forums. You can buy direct from them, which means any problems will be handled directly by the people responsible for importing and setting up your machine. You can also buy from authorized dealers who then become responsible for all servicing and support. If you are contemplating purchasing the machine from an authorized dealer, contact them in advance and ask about their support policy on that machine, its motor, parts and accessories. The owner of the Cobra brand name, as well as Leather Machine Company, is Steve Tayrien. He is a member here, going by the handle Cobra Steve

Whomever you buy a new sewing machine from, make sure they can both service the machine if necessary and give you personal technical assistance when operational problems arise. Shipping is a two way proposition if the machine needs to be shipped back to the seller for repairs.

The Singer 111w103 is a compound feed walking foot machine, one generation before the model 111w155.. It doesn't have either reverse or the shuttle jam protection clutch. As long as you hold back the starting threads (top and bottom) and never let the top thread jump out of the top tension disks, and never let the bobbin thread bind in the case, it will do a fine job sewing Naugahyde, banners, garments, webbing and leather, up to about 5/16 of an inch, with up to #138 bonded nylon or bonded polyester thread. It uses the standard system 135x16 (leather point) and 135x17 (round point) walking foot needles. Most jobs sewn on these machines are sewn with #69, 92 and 138 thread, using #18, 20 and 23 needles, respectively. The machine is manually oiled and is good for speeds up to about 2000 stitches per minute, or down to one per second.

It could be the thread having too much coil action off the spool. The twists and turns from twisty thread cause tension changes and possibly even skipped stitches. This is especially likely if the thread loop twists away from the hook on the upstroke. Sometimes it helps to wind the top thread once around the top post in the opposite direction to the natural twist of the thread.

There is an image on the lower left of the CB4500 page with a photo copy of their ad from Shop Talk magazine. Click on it to see a larger readable view. Turn off your ad blocker if you don't see it. Sometimes, just refreshing the page will get it to reload and display.

Joe; You asked about "stitch by stitch sewing" I can do that with any motor I have, including clutch motors. You have to treat the foot pedal like you are driving a Beetle or Fiat, or some other small clutch operated car. You slowly move the toe down until you feel the motor start to engage. There is an adjustment bolt on the right end of these motors that lets you adjust the free play before the clutch engages. All clutch motors accept a standard inside diameter (usually 20mm) type 3L, v-belt pulley. Type 3L v-belts are 3/8 inch, or 10mm across the top and are the standard for the industrial sewing machine industry. These pulleys are made in outside diameters ranging from about 40mm, up. I have found that I can feather one with a 70mm pulley as well as one with a 50mm, down to 1 stitch per second. The difference is in the top end. The 70mm lets you sew about 50% faster with the pedal down. If you buy a servo motor after the machine, it may need some special linkages or changes to where the linkage bracket is connected to the floor pedal, to line it up under the control arm. Most servo motors have the control arm facing forward, towards the operator. All clutch motors have the leever under the motor, facing sideways and connecting on the left end, via a ball joint, straight down to the pedal.

Joe; I would go with the Juki and learn to feather the clutch first. If you have trouble controlling it, change the motor pulley to one that is 50mm or 70mm in diameter. This will slow down the machine at all times and may not let you get long runs done as quickly as normal upholstery machines. If you charge by the hour, faster is better (in upholstery). The Juki is capable of sewing quite fast, when needed. If you find you have a hard time controlling the slower speeds on the clutch motor, look into getting a servo motor. Try to find one with your available voltage and connection, which is rated at 1/2 horse power or better and has a rotary knob to limit the top speed. I have three motors like that, two of which are the Family Sew model FS-550s. I don't know if that motor is available in 220 volts or not, but others probably are. It is even possible that the same company ships a different brand name of the same motor to European customers. The advantage of this type of motor is that you can just twist the knob to slow it down to about 2 stitches per second flat out. Twist the other way and it will drive the walking foot machine as fast as it can go. You get slow speed accuracy, plus high speed money making capabilities, all in one motor.

Thank you Uwe for that research.

I have a little side business refurbishing and selling old iron Singer sewing machines. The oldest one in the rack right now is a model 27, from 1902. I cleaned, oiled and lubed it, then adjusted the clearance of the bullet shuttle. That 114 year old machine sews 2 layers of 4-5 ounce leather, denim jeans and just about anything I can fit under the foot, with #69 bonded nylon thread. The Sphinx decals are in good condition. It amazes me that nobody has expressed the slightest interest in buying the machine. Quite frankly, I don't care. I know I can cart it into my shop (15 feet away) and sew with it in one minute or less. It does one thing and does it well. It sews tight, straight stitches, up to 5 to the inch. One hundred fourteen years and still going strong. It thrives on oil, clear grease and fair treatment. With more of the same, I expect that it will be capable of continuing on its timeless journey for another hundred years. Treat your Cowboy machine with the same respect and it will outlive you.