Wizcrafts

The Juki LU-1508-NH is rated to use #207 thread, top and bottom and has a U size bobbin and double top tensioners. It can sew up to 10mm long stitches and has true rectangular feed on the bottom. It can actually sew up to 1.2 inch of material. The feet lift up to 5/8" to allow thick seams to pass under them. To allow for higher lift and thicker sewing, this machine is equipped with System 190 extra long needles. The inside work space (harp) is 5" x 10 inches. Is this enough space to roll the material up if you are sewing inside? This might be important if you sew on labels, Velcro or webbing. If 5x10 isn't sufficient, you'll need to look into long arm, high harp, tarp and sail sewing machines. They have up to 3 feet of work space to the right of the needle. My long arm has 20 inches.

I have a Singer long arm machine that was upgraded to a U bobbin system over a decade ago. When it works right, it is great! But, it jams either the top or bobbin thread at the slightest provocation. This could be from starting or stopping suddenly, or turning a corner too fast. If I don't hold back the top thread just right when I start, it jams in the hook (and, I know what I'm doing). The other day, while I was in the midst of sewing a gently curved rocker patch onto the back of a vest, the thread jammed the machine to a halt. I had to cut the thread stubs off over and under the vest. I discovered that the bobbin thread had actually wrapped itself up and under the spring loaded bobbin securing clamp and around the bobbin post! It looped right around that sucker! My G size bobbin Singer machines don't normally have these problems. This isn't to say that every Singer or clone machine that gets modded to a U bobbin will have troubles like mine. In fact, I suspect mine is an isolated problem. That said, the risk of introducing new problems is real.

Maybe the presser foot bar is binding when it is in the lifted position. If so, loosen any set screws that might be holding in bearings on the top and bottom of the presser bar. If that drops the foot, find the best position and tighten the screws to keep them in a good spot. It would help to pull out the presser bar and clean off any residue or dings with emory cloth.

I have a similar machine in my leather and sewing shop. The machine pulley is a fixed size. You probably want to replace the motor pulley with a 2 inch pulley. You need to measure the diameter of the shaft, then eBay it. Or, order from one of our supporting dealers, like @CowboyBob. I think that clutch motors have a 3/4 inch shaft, while most servo motors are 15mm diameter. Once you know the diameter, order the small pulley and also get a new v-belt that is that much shorter. The old belt will be too long and the motor may not have enough adjustment to compensate. V-belts have their length stamped somewhere on the outside. A typical -belt for a 4 inch motor to 4 inch machine pulley like your setup might be 44 inches. But, it could be less. The new belt would be 2 inches shorter if you get a 2 inch motor pulley.

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The feed dog is way out of position.

The Cobra 26 is a compound feed walking foot machine. There is no needle hole in the throat plate. The needle hole is inside the feed dog. The throat plate has a rectangular cutout to allow the feed dog to move from front to back.The needle bar moves in sync with the feed dog and inside foot. The needle should always go through the hole/slot in the feed dog.

On my Cowboy CB4500 and my friend's Cobra Class 4, both of us can back off the top tension disks spring to the point that there is no tension at all. This is the same lack of tension we get when we lift the feet all the way with the hand lifter knob, or foot lifter pedal. When you lift the feet does the tension drop to, or close to zero at the disks? If the tension can be set to zero at the top disks, can the same be done by backing off the beehive spring on the bottom roller? Standard procedure is to wrap the thread around the bottom roller 1.5 turns. Check the tension as the thread exits the bottom roller. Move on to the check spring. Is the spring able to move up and down as the take-up lever moves up and down? Inspect the inside of the loop at the end of the spring to see if it has a burr, or is somehow pinching the thread. Inspect the thread hole in the take-up lever for burrs. Inspect the lower thread guides, including the thread hole on the needle mounting clamp. You need to figure out where along the thread patch the tightness is coming from. Maybe it is the spool itself. Is it cross-threaded? Once you are able to set the path to zero tension, balance the top and bottom. You should be able to back off the bobbin tension to a bare minimum and balance the knots. Make sure you're using the best thread and needle combination. Consult this needle and thread chart.

Do you realize that you have posted your name, address and phone number in plain view of anybody reading these posts? I hid them for your protection in case the harvesters didn't scrape them already. Take matters like this to private messages, not the publicly viewable forums.

@TES When you removed and replaced the shuttle retainer plate, did you leave some slack in the spring covered retainer securing screws? They need room to float as the top thread goes around the bobbin case. I back mine off 1 full turn for #277 thread and above, or 1/2 turn for smaller thread sizes. If you tightened the screws all the way down, there's no room for the thread to push out the shuttle as it goes around. This adds tension to the top thread and can actually pinch or jam it.

Are you holding back the starting threads for a few stitches? This is a necessity! When you start sewing, can you confirm that the top thread is going inside the inside foot and exiting out the back of that foot? If the top thread is fed between the inside and outside foot, there will be trouble. How much swing/travel does the check spring have? It must hold the top thread taut until the needle has penetrated the top layer. and must stop moving down before the needle reaches BDC. If your chec spring travel is too short, there will be too much slack in the top thread as the take-up lever moves down. This could lead to the thread getting caught by, and wrapping around the feet.

I wonder if it is a special model double needle machine? That would 'splain the second bobbin cover on the left.

@MacB I found these bobbins for your machine, from the seller Evernice.

A #25 needle is too large for #207 thread. The hole will be too loose to grip the knots. Move down one size to a #24. Use leather point system 794 (7x4) when sewing leather, and round point 7x3 when sewing cloth, webbing and bio-synthetics. I don't know how you've threaded the machine on the top, but, make sure that the thread isn't rising up in the top tension disks as you sew.This may call for re-positioning the thread guide just below the disks. Also, it helps to wrap the thread counterclockwise around the top and bottom holes in the top thread post. I feed in through the top inline hole, wrap CCW, and feed out the bottom inline hole. This provides needed back pressure on the top thread which helps keep the thread from twisting and lifting out of the business part of the disks. Whatever needle you install, make sure the rib is facing due left and cutout scarf is facing due right. If the bobbin thread tension is too light, the knots will come out the top to easily. Reverse the direction of the bobbin so it makes are sharp turn and feeds against the direction of the path to the spring outlet hole. If it's too tight, feed straight in and reduce the spring tension. These machines need a fair amount of bobbin tension to offset the big spring in the tension system.

@Crockett Know that just because your machine can clear 3/8 inch of material and sew it, that material can't be very dense and incompressible. So, while that machine can sew together 3/8 inch of upholstery leather, it can't do the same with hard veg-tan in a shaped holster. The moving parts aren't secured strongly enough to hold together under the strain of trying to penetrate that thickness of hard temper leather, especially if you are trying to sew with #207 thread using a #24 needle. The best you can hope for is the sew 1/4 to 5/16 inch with #138 thread, using a #23 needle. Number 138 (T135) bonded nylon thread has 22 pounds breaking strength. I wouldn't trust that size thread to hold a serious holster together unless you also rivet the layers in case the thread breaks under stress. FYI: All of the holsters my partner and I produce are sewn with #277 thread, on top and bottom, using a #25 diamond or S point needle. I use a Cowboy CB4500 harness stitcher that I got from Toledo Industrial Sewing Machines in 2011. Before that, I used a Union Lockstitch Machine for holsters, sheathes, weight belts, gun belts, and anything over 1/4 inch thick veg-tan. The thinnest holsters we make are 1/4 inch thick. The thickest was 1 inch. The average is 1/2 to 5/8 inch along the edge that has a filler for the trigger guard and bottom profile..

Buy them a new needle clamp and screw. Simple fix.

Try here: https://www.youtube.com/watch?v=pQGPdiY6m9U and here: https://www.youtube.com/watch?v=iuzoN-I6ydI

Yes. Make sure it isn't either retarded or advanced to start your troubleshooting.

@Icho, This is often caused by retarded hook timing. Try advancing the hook a little and see if it reduces the tension going around the hook. Also, increase the slack setting in the check spring to feed a little more top thread into the mix.

It could be a thread problem. If you have, or can buy more thread, try a different spool. Also, inspect the tension spring on the bobbin case to see if there is any thread fluff stuck under it, or inside the bobbin case. Make sure the timing is spot-on and not retarded. Try adjusting the travel and slack settings of your check spring.

Perhaps you can reduce the tension and travel of the check spring to loosen the lay of the stitches. They call it a thread take-up spring in the manual. Here is a link to page 11 where the adjustments are outlined (in Chinese and English). In essence, the spring movement only needs to continue until the needle pierces the top of the material. If you setup the machine for thin material, the spring may be holding on way too long. If there is a second adjustment for the amount of slack thread, increase that amount. The actual spring tension will need to be fairly strong for #207 thread. IHTH

I think that the top thread is getting pinched as it exits the shuttle and bobbin case. It looks like the case opener lever isn't pulling back the bobbin case to give its tab some clearance for the thick thread you are using. Try setting the opener arm so it pulls the case backwards as the thread moves around and past the bobbin case. Also, play with the check spring travel and position settings to get a little more slack in the top thread.

@Jpmaringa, It is definitely an Adler short arm shoe patcher. If you can open the bobbin cover plate and take a picture of the bobbin and shuttle, I can tell you if it has a large or small bobbin. Also, post a picture of a needle, next to a ruler so I can identify whether it is a high or low lift model. These details will define its thickness capabilities and thread capacities.

@Cali514, this motor can indeed be swapped for a servo motor (if necessary). I regard this setup as a standard motor and pedal alignment. My Adler is mounted on a steel stand made by Adler. It isn't easily modified. The one you are looking at can be modified and accessorized. If you do buy the patcher, don't change the motor right away. You need free play to hand turn the balance wheel. The clutch motor has a big bolt that's shown in your photo. That bolt can be screwed in or out for more or less free play before the clutch engages. A servo motor may have zero free play before it engages. But, it may have a brake pad that can be removed for free play. However, that means you lose the brake! That's how it is on the servo motors in my machines. The ones with the brake removed have to be slowed and stopped by grabbing the rotating wheel. There are different types of servo motor.

I own an Adler 30-7. It is meant for repairing tears and loose stitches in shoes, boots and cylindrical items, like cue cases, pants seams, and, as was mentioned earlier, for sewing patches over pockets and linings on vests, and jackets. It is a great machine for sewing in zippers in purses and boots. The bobbin is called a large bobbin in "Patcher Speak." This translates into about half the capacity of the bobbin in a Singer 111 type machine's "G" size bobbin. Those bobbins are usually referred to as 1x capacity in the industrial sewing machine World. Judging by the small diameter of the post, that tall post machine likely uses a Singer "G" bobbin. That is a perfect machine for making and repairing hats of all kinds. You can also sew along the top of a bag and the very bottom of a bag. TBT, I would buy them both, then find a good working condition Singer 111w155 or 156 flat bed machine. If you know how to ride a Harley, a clutch motor is no big deal. You already know how to feather a clutch. Otherwise, there will be a learning curve. If the Adler is on a matching power stand, it will contain a 1/2 horsepower clutch motor and 1 2:1 speed reducer. There is a custom bracket bolted to the left side of the motor actuator arm that comes out the bottom of the stand and connects to the "gas" pedal. It will not be easy to replace this setup with a servo motor, if it is doable at all. Deal with it and feather the clutch. What you haven't been told about the Adler patcher is that is has a revolving foot that feeds in 360 degrees. There is a screw on the front of the revolving head housing to lock the foot in position to "try" to sew a straight line. There are no edge guides, so straight lines are tricky. Don't attempt it if you are stoned! EDIT: It looks like the Adler has been custom mounted to a standard, but shortened industrial sewing machine table. I can't see the bottom of it where the speed pedal is located, so again, no idea if it can be converted to a servo motor. I would just go with the motor they have in it. Clutch motors are very easy to adjust for slack movement before they begin to engage. Not so for most servo motors.