Wizcrafts

I've added some new details to my post #51. If you read it when I first posted, please re-read it.

Ken; Read my post #49. I talked you up as having made good points at the beginning of it. I also disclaimed being an expert. I'm not looking to get into fights here; heck, we've never even met. Everything I post is either my opinion, or from my experience; mostly the latter. The dealers and their paid mechanics are the experts.

Steve; I wish that we could produce motors right here, in the USA, for a reasonable cost. This is so frustrating. I have ideas, but no money to try them out. It sucks being me ;-( Here is what I did to Steve's motor to improve its controllability. First, I set the chain from the pedal so it had only a little slack. Next, I turned the adjuster screw until it was just in the off position, then backed it off another half turn. I had to remove the rubber tip to accomplish this. I also set the top speed to about 3000 rpm, to reduce the shaking of the machine. This shaking was actually causing some skipped stitches. The next item that made a difference was loosening the nut on the speed reducer, turning the wheel by hand to set the belt in a happy place pull-wise, then tightening it again. This allows me to handwheel around turns, where the motor is too touchy. It also reduces the strain on the motor and allows me to have better control at slow speeds than was the case when it was very tight. I really want to open up one of these motors and see what can be done to fine tune the light baffle. I play steel guitar professionally and use a light beam volume pedal. There is a mechanical adjustment inside my pedal that allows me to control the off and full on settings. It does this by repositioning the variable density light filter, which is mounted on a piece of hard wood. Yes, it's Hillbilly engineering, but it works flawlessly! That device will gracefully change my volume from zero to 100% over a wide range of easily controlled foot movement. It even has a trim pot to set the sensitivity. So, I know that these things can be done. My SewPro 500 motors have what I think is capacitive, or proximity drive, activated by the big lever under the motor. As one's foot pedal pulls down on the lever, the crank on the inside moves one electrically charged piece of metal towards another that is on the back of the motor (stator?). As it moves closer, the unit begins to spin. At a certain point it is physically stopped and reaches maximum velocity. The two pieces are separated by a thin dielectric insulator, to prevent arcing or meltdown. The starting position of the moving element is adjustable by a long hex-head screw, There is a brake that is also adjustable internally.

Ken brought up some really good points and suggestions. Newbies would do well to read through his post, #44, in this thread. I never claimed to be an expert. I am just an experienced sewer-rebuilder, with some time as a worker bee in an industrial sewing machine store (Juki machines galore). I've put in hundreds of hours sewing everything from cloth, to vinyl, to leather. I have rebuilt many sewing machines, including two Union Lockstitch machines and gone through many machines that were supposed to sew leather, but did so poorly. Until recently, all of my machines had clutch motors. I learned to feather the clutch to sew slowly and can still do so. I can adjust the action on a clutch motor to allow the range of free motion I prefer, where it releases the brake, but before it engages the drive. Most of the servo motors lack any such freewheeling/braking adjustments. The exception is the SewPro 500GR (now sold as the "Toledo Sew Slow") motors sold by Toledo Industrial Sewing Machines. I currently own two of those motors and have adjusted to behave much like clutch motors (release brake-engage slow-go quick-go fast). It's too bad they are (currently) a little under powered for a long arm 441 or Adler! I have a Cowboy CB4500 at home and sew on a Cobra Class 4 at work. Both have common servo motors. Both are now into their second motor. I can feather the speed control on both motors to sew around one stitch per second, or one stitch at a time. One of the motors is touchier and drops out with a violent shake if I try to sew under one/second. This is a design quirk in the electronics that controls the unit. There is nothing that can be done, other than try to avoid that awkward spot. The other motor sews more slowly, about one every other second, then simply drops out with a whimper, rather than shaking the entire table and machine. Both of the motors I use on these 441 machines are somewhat temperamental and have a rather limited range between just on and full on. Still, there is enough range of motion if I am careful with my foot and keep steady pressure on the floor pedal. Thankfully, I have a steady foot, but recognize that others may not be so fortunate. They will have a harder time controlling their motors than I do and their concerns need to be addressed. Art once referred me to an SCR servo motor system that has tremendous torque at even the slowest speeds and Trox speaks highly about the Efka motors he uses. Both cost much more than the servo motors that ship on the 441 machines. Some of our dealers, or non-member dealers known to us, already stock higher-end servo motors, which they will happily sell to anybody. But, this topic is about the motors that are included as standard equipment on new machine purchases. I promise you that this is being worked on. <rant> They copy, but do not improve our machinery and electronics! Sometimes, their QC is lacking. Sometimes they use the cheapest marginally acceptable components, such as light sensors. They know who they are. Their alphabet is known in code-page as the Big 5. </rant>

The topic is about a Cobra Class 4, which IS already equipped with a speed reducer pulley. My Cowboy CB4500 uses the same pulley (~3:1) reduction system. By the time the small output pulley feeds the large one on the flywheel, we are looking at anywhere from 8 to 9 times speed reduction and torque multiplication (depending on motor and flywheel pulley diameters). I am hopeful that this discussion will lead to the development, or discovery of a better motor for these machines; one which won't drive the price up too much higher. There are already better motors available, but they cost a lot more than the servos included as standard equipment. I can assure you that our dealers are discussing this matter and looking into possible alternatives. However, these new motors need to be tested under load for prolonged periods of time to ensure they can stand up to the heavy loads imposed by big machines sewing heavy leather, with big needles and thick thread.

RamRod; Then your problem is that either the timing has gone out, or the bobbin and shuttle cannot clear #138 thread, due to too tight vertical adjustment. Do you have manuals for this machine? A mechanic's manual will help you set the clearances and timing.

You're right: it makes no sense, until you get into thicker and harder to knot threads, like #415. Then, one would preferably use #346 on the bottom to aid the forming of lockstitches. Some folks using #346 on top will use #277 in the bobbin. It is marginally weaker, but knots easier than 346. Otherwise, the smaller thread becomes the weakest link in any mission critical sewing. If your Pfaff can properly tension #138, top and bottom, go with that thread. Use a #22 or #23 needle. Use a regular point for your webbing, and leather point for leather collars or leads.

A thread rat's nest under the material is usually caused by a total lack of top tension. However, the bobbin thread is usually picked up in those situations; it's just tighter on the bottom than the top my a magnitude. Failure to pick up the bobbin thread can be caused by the bobbin thread jamming inside the case, or timing that has been thrown out by a jam, or the wrong needle size or orientation, or a bobbin shuttle that is too tight in its housing and won't allow the thicker top thread to pass both over and under it. Finally, the check spring position can have some effect of the forming of a loop under the throat plate. You are going to have to take off the throat plate and watch the needle come down and ascend in a narrow test strip. Hand-spin the wheel slowly and see what is happening to the top thread when the shuttle point passes the cut-out in the needle's eye region. First of all, the eye must be under the point as it passes by. The loop must face up and out to get picked up. Once picked up, the top thread should be carried around the bobbin case, feeding both over and under it smoothly, without any hang-ups. Do what you must to make these things happen. Bobbin shuttles are screwed onto the shafts that turn them. Needle bars are screwed into the arms that move them up and down. Screws can come loose and timing can change. Another thought is if you are using the wrong needle and bobbin for your thread, it might unravel and rat out on you. Are you using left or Z twist thread? One of the bobbins rotates in the best direction for common left twist thread. The other bobbin turns the wrong way and is meant for right twist thread.

Gregg; My 31-15 is very old. I believe it is older than 1920. The machine came with DBx1 needles when I got it. They are perfectly centered in the hole in the throat plate. I have some old stock of system 134 needles that I wanted to use in the machine, but, they hit to the left of center in the hole. Some work okay, others skip stitches. The DBx1 work perfectly. Maybe my needle bar was made for these needles back then.

If you want to show photos of how well the machine was degreased, post here. I would start a new topic to show off your continuing work on it.

SOLD Please close topic.

Are you using the proper needle system (16x257, DBx1, DBx257, or 1738)? If you got the machine with the wrong needles, they may be too long or too short. If the needle is not correctly aligned it will not pick up the bobbin thread. Verify that it is fully inserted up into the needle bar and that the cutout section around the eye is on the right. The thread must feed through the eye from left to right. Have you threaded the machine correctly (see photos below)? Is the bobbin thread coming out from under the bobbin tension spring opening, as in the photo below? Is the bobbin case snapped into the retainer in the shuttle housing? If the needle is installed as I described and a threaded bobbin is in the bobbin case, with thread sticking out a few inches, and the top thread is correctly fed through the guides and tensioners, the usual cause of failed stitching is that the needle bar has slipped in its mount, from heavy impacts trying to sew hard leather and needs to be retimed. This may require personal assistance to teach you to set the eye of the needle in exactly the correct position for the shuttle point to pick off the loop..

I suspect that the problem with these motors lies in the quality of the movable light baffle, or maybe even in the light sensor module itself. If I can get my hands on one of these motors I will play with it and see what I can learn about any possible mechanical adjustments that can be made to spread out the speed over a wider range of motion.

Maybe we can work something out on the ULS. Mind you, the Cowboy is easier to master.

People used to tell me that these machines can't sew thin material, but I ignored them and did it anyway. I even shorten hems on jeans on my Cowboy. I have a table top attachment that helps keep flat work flat, rather than letting it fold over the arm. It's a very versatile machine once you get to know it.

Here, as promised, are some photos of my CB4500 sewing webbing. One layer is about 1/20 inch. The needle is a #23 leather point. The thread is Cowboy #138 pre-lubricated bonded nylon.

I had time to sew the webbing, but not photograph it. I'll do that later today. It sewed one layer, two layers and 6 layers without hesitation. The knots are hard to hide in one layer, which is only about 1/16" thick. I would normally use #92 thread for that thinness.

I am working on a computer right now, but will dig up my webbing and sew it in a couple hours. I'll post a photo of the results.

Okay, how thin do you need to sew? I have some webbing on hand. What number/size of thread are you going to use? I'll sew a layer or two on my Cowboy stitcher and get back with you. The part of your description that deals with the leather leashes reaching 1/2 inch is really the crossover point. You will damage the upholstery machine trying to climb that thick. I wish I could tell you otherwise, but I'd be lying.

Have you contacted Ferdco? They are still in business and should be able to solve this problem. I don't know which machine your Bull was built on. The issue you are having may be specific to a Juki, Seiko, Adler, etc, etc. Methinks it will be something in the shuttle area that is responsible for the needles breaking. Perhaps a burr from a previous needle strike, or a retarded or advanced shuttle hitting the needle instead of gliding past it. Maybe the needle bar is loose in its mount and has shifted laterally? Try using a #26 needle fer the hellofit.

Sometimes the math works and other times it fails. There is more than one factor that limits the thickness you can sew. The length of the needle, from the bottom of the needle bar to the eye of the needle. The clearance between the outer presser foot when it's raised all the way up, and the needle bar when it's all the way down. The height of the cut out in the back of the head, in which the alternating foot levers raise and lower. The strength of the presser foot spring, or springs The mechanical position where the upper tension gets automatically released by the foot lift mechanism Excess slack in the shuttle drive system could retard the timing making it harder to sew thick material. The standard walking foot needle system is not long enough to let the feet lift high enough to sew over 3/8 inch, without the needle bar hitting the raised outer foot. But, a manufacturer might decide to make certain models have higher non-sewing foot lift to insert the work into the needle area, clearing hardware and thick seams. That would be about 1/2 inch maximum clearance on a standard walking foot machine. The Juki 1508NH has been modified to allow the feet to lift even higher, to clear obstacles like the sides of shoes. Once the work is clamped down under the foot, it will only sew up to 7/16 inch. The needle system doesn't quite allow it to sew 1/2 inch. The 1508NH lists for about $2500, the same price as most 441 clone machines that can sew over 3/4 inch. You really should be limiting your search to a machine that can exceed your requirements, rather than just barely meet them. Another factor you may not know about yet is speed reducers. All of the 441 and 205 type machines have a 3:1 speed reducer pulley between the motor and machine. Furthermore, the flywheels on the big machines typically have 8 inch pulleys, or more. This slows down the top speed, multiplying the torque and gaining the necessary punching power to sew thick or hard leather, with large needles and thread. The upholstery grade machines don't usually have this reducer and might not be able to power the machine through the hard materials.

Ronnie; He told me is is making both nylon and leather dog collars and leashes. Some will max out at 3/8" while others may approach 1/2" at the folds. It seems certain he will need to sew up to 7/16 inch.

Consew now owns Chandler and sells equivalent models under the Chandler brand for a couple hundred dollars less than the Consew branded machines. They are about the same quality. A dealer can tell you the actual difference between them. The Juki 1541S is a slightly higher quality machine, tolerance-wise and is used in factories around the World. But, all three of these machines have exactly the same sewing capabilities. These are 3/8 inch thickness sewn, with no more than #207 thread on top and preferably, #138 in the bobbin. They use the same standard walking foot needle system: 135x16/17. The largest needle available in that system is #25. All three are upholstery grade machines. They can sew 3/8 inch, but not all day, every day. They will be maxed out and put to their limits working at that thickness. If you intend to sew 1/4 inch on a steady basis, they will do a good job. They aren't really built to take the constant pounding of sewing hard leather, especially with #24 or #25 needles. If you plan on sewing at or above 3/8 inch on a steady basis, these machines will let you down. There is one Juki you didn't mention, which exceeds all of these machines in capacity. That is the LU-1508NH. The feet lift up to 5/8 inch. It uses a longer needle (system 190) and can sew up to 7/16 inch, with #207 thread. The 1508NH sells in the mid 2k range. After that, you need to move up to a 441 clone, like the CB3500 you mentioned.

The Singer 111w152 IS a walking foot machine. It does not need any walking foot attachment! Here is the technical specs for this model: Single needle, lock stitch, compound feed with a vertical-axis sewing hook, and alternating pressers with 3/8" lift. Safety clutch prevents hook from being damaged by accidental strain. Speed 2900 R.P.M. The maximum stitch length is 5 to the inch. For stitching light leather work, such as leather gloves. This model is not designed for thick or hard leather, nor for thick thread. If you want to have a machine that sews with the same (#554) waxed linen thread you typically use when hand sewing, look into a Union Lockstitch, or Campbell-Randall needle and awl machine, or a shoe sole stitcher (Landis, Champion, American Straight Stitch, Frobana, Gritzer). None of the standard closed eye walking foot machines can feed this thread effectively. If you want a closed eye leather sewing machine that can handle thick, unwaxed thread, the Juki TSC 441, or Adler 205-370, GA5-1, or the 441 clones (example), which are sold by our member-dealers, all work with up to #415 bonded nylon, or bonded polyester thread. They require a #27 needle to do this. I do not personally know of any other types of machine that can use a #27 needle. The machines I have listed above will sew over 3/4 inch of real leather, with up to #415 bonded thread and huge needles. They sell for between $2,500 to $6,000, plus or minus.

Absolutely! Contact Campbell-Randall, in Yoakum, Texas! They build them to this day.