Wizcrafts

Call Bob Kovar, at Toledo Industrial Sewing Machines (866-362-7397). He has all manner of screws and other parts for industrial sewing machines. Otherwise, any authorized Juki dealer can get them for you.

The bottom stitches look normal to me, for a typical walking foot machine. The only way you can get a different result is to use a straight stitch machine with a hole in the throat plate that just clears the needle, or, find an elusive narrow slotted throat plate and remove the feed dog. This converts the machine into dual feed: needle and inside alternating foot. You should experiment with different needle points. There are left LL, LR, Diamond/Triangle, S, P and round points available from different manufacturers. One may give a better bottom hole appearance than the others. If you find such a needle, order it in all the sizes you intend to use.

Weaver Leather might be able to make a customized foot from an old one, if they have one laying around. Otherwise, finding an affordable Adler foot to modify may be an elusive task. Otherwise, seek out any Adler dealers, both in North America and Europe. College Sewing in the UK has lots of obscure parts. Our members down under may have a foot for that model. Ask Darren Brosowski, in Australia

This could be really expensive, as his machine is an Adler 205-370. It is what it is.

Big Sioux; I am referring to a post with holes that you might have on top of the sewing machine. My CB4500 has such a post with 4 holes bored into it. The top and bottom holes are aligned the same direction, inline with the thread path, while the two middle holes are on different angles facing across the machine. If the thread is very twisty, I sometimes feed it though the top hole, wind it clockwise around the post (looking down), then feed it through the bottom inline hole. From there it's on to the guide below the top tension disks and onward. This seems to counteract the twistiness, if that twist was counterclockwise off the spool. Otherwise, looping it counterclockwise around the post provides the sometimes required back pressure to keep the thread from twisting up out of the tension disks.

That is the same setup I have. It was setup that way by Toledo Industrial Sewing Machines. Other dealers may do the same things to machines they sell. As I said earlier tonight, my FS-550s motor alone had trouble driving the big machine from a dead stop into a double thickness of 10-12 oz bridle leather, at low speed settings. These motors have much less torque at slow speeds that clutch motors. The 3:1 speed reducer adds the torque that is missing to get the machine sewing without handwheeling it from a dead stop. You noticed that your clutch motor continues turning the machine after you power it off. It is one of their foibles because they are so powerful. Servo motors have a tiny bit of power after you turn them off, but not more than one or two stitches, if it was set to a higher speed when you last ran it. Long time operators of machines with clutch motors learn to heel back hard on the floor pedal to lock the brake in place. The motor keeps turning but the machine doesn't. I heel back, raise the feet with the knee lever, pull the work out, cut the threads and move along. All the while, the motors keeps spinning until it simply runs of of go. I think you will be very happy with a FS-550s motor and 3:1 reducer combo. Make sure the dealer supplies the proper set of v-belts. You need two belts of radically different lengths. I think my motor to big pulley on the reducer is about 38 inches, while the small reducer pulley to the machine is about 59 inches. Both are type 3L belts. Ask for the best welded belts they offer. Belts are made differently by different manufacturers. Some cheaper ones are welded out of alignment and will cause a thump once per revolution. This becomes a serious shake at higher speeds. An opened v-belt that lies perfectly flat on a flat table will usually run true.

I just re-read you problem report. It seems that your stitch length changed when you walked up onto another layer, then returned to your preferred length once back on the original thickness. That is a whole nuther issue than I addressed. This unwanted change in stitch length with changes in thickness could be caused by an incorrectly set inside foot position in relation to the needle, or incorrect adjustment of the alternating height of the two feet. A good starting point is to remove the material and hand wheel the machine until the tip of the needle is at the height of the feed dog. Stop wheeling here. Loosen the big bolt on the mid-back of the head that controls the position of the inside foot and lower that foot to hit the feed dog with the tip of the needle. Lock down the bolt. Try sewing a sample piece. If the problem persists, try adding or subtracting pressure on the outside presser foot. This is usually done via a threaded hollow screw on top of the left end of the head, directly over the presser bar. I usually back off that spring action until it has just enough force to keep the leather/material from lifting with the ascending needle. Also, check the feed dog for free motion. It should not move from finger pressure alone. If it does some screw is not tight. There are two little screws that secure the feed dog. You have to remove the throat plate to get at them. Use a long, narrow blade screw driver to tighten them down all the way (keeping the feed dog aligned straight ahead). If those screws weren't loose and the feed dog still moves forward and backward by your finger on it, the bolts under the end of the body may be loose. You'll have to flip the machine back on its pivots to see those cranks and moving parts that move the feeder. Check the shaft that the feed arm is mounted to. It has cone shaped bolts on the left and right ends that set the position and slack. The screws should allow the shaft to move, but not so much as to be sloppy. The goal here is to have all feed parts moving smoothly, without binding and also without excess slack. Keep every moving part oiled. A properly adjusted walking foot machine won't have much difference in stitch length unless the thickness changes from one preset thickness up to 3 or 4 thicknesses. Then the pendulum* effect overrides your desired stitch length and you will have to compensate manually. But, a change of one layer shouldn't change the length that much, like you described. * The pendulum effect is the change in stitch length in a large difference in thicknesses being sewn. It is due to the fact that the needle bar is mounted at the top of the head and it swings like a pendulum as it sews forward and backward. Material that is higher up from the base level meets the needle sooner and the needle moves a shorter distance up there than it does close to the base of the machine.

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.