Wizcrafts

Juki uses those prefixes to assign the intended end use, or sometimes the bobbin size of the machine. The suffix describes certain capabilities of a sub-class. A DNU machine is a typical medium to heavy duty, triple feed upholstery walking foot machine, while an LU is a heavier duty walking foot machine. Both use a double capacity U style bobbin. The DU series are top and bottom feed walking foot machines. The DDL are bottom feeders only and are better suited to cloth or non-sticky materials..

I usually first unthread the machine. Then follow this sequence... Remove the screw above the needle securing screw then pull off the needle clamp assembly from the bottom of the needle bar. Try to drive out the tapered pin holding the take-up barrel to the needle bar. It drives out from the back. Unscrew the four bolts holding the rounded head to the left side of the body. They are on the right side of the head assembly. Two near the top and two near the bottom. If operation #2 was successful, go to #5. If not, go to #7 Carefully pry the round head assembly off the body. Hold the needle bar at the bottom so it doesn't fall to the floor, then pull it completely away from the body and lay it down. Pull out the needle bar for inspection and cleaning. Use Emory cloth to smooth any thread tracks and replace the tiny paddle shaped spring if it is worn or twisted. Reinstall the tiny screws for the paddle spring into the same positions as they came out! This spring is important! If you can't drive out the tapered pin holding the needle bar to the take-up barrel, pull the head away at a suitable down-left angle to let the needle bar smoothly exit as the head is pulled away. Avoid hitting the end of the cylinder arm. The needle bar will be left hanging from the top knuckle joint on the take-up barrel. With the head in hand, unscrew two screws on the bottom that hold the revolving bushing to the inner parts. Remove the butterfly ring and stitch length motion assembly and separate them. Check the hollowed ring for damage, then clean and oil it, or replace if damaged too badly. The part with a puck on the end that rides inside the ring is what wears out. Either buy a replacement part or braze bronze rod over it and taper it with a file. Shape for the best fit with 360 degrees rotation and polish on a buffer. Reassemble, oil and hopefully get 5 stitches per inch at 1/8 inch thickness.

Machines that are capable of sewing 5/8 inch of leather, with a regular closed eye needle, use system 794 (aka: 7x4) needles, which are at least an inch longer than System 135x16 walking foot machine needles. They are typified by the Cowboy CB4500, Cobra Class 4 and Techsew 5100 machines. They have massive pressure and tension springs, cranks and take-up arms. These machines don't do as well with thin needles and thread, or thin, floppy leather or cloth. Their design specs call for thread sizes 138 through 415, using needle sizes 160 through 230. The needles are the size of roofing nails.

I was not implying that a Cobra 26 is limited to a quarter inch thickness. I was just agreeing that it could sew the 15-16 ounces the members wanted to sew. Later information suggests that the machine can tension #207 thread. This makes it a very good intermediate duty machine.

You are confusing the maximum foot "lift" with the actual sewing capacity. With walking foot machines you lose between 1/8 to 1/4 inch of capacity under the raised feet. This is because the feet have to alternate up and down to move the material. So, when a manufacturer says that the feet lift 1/2 or 5/8 inch, they do, but only to insert and remove tall objects on the work. Once the work is secured under the lowered feet, it must not exceed 3/8 inch. The top to bottom stroke of a System 135x16 needle is insufficient to negotiate anything thicker. If you buy a Model 26, have the seller sew a test strip of a 3/8 inch stack of veg-tan with the thickest thread it can properly tension and pull the knots up between the layers. Or, ask them to sew the thickest stack that can be sewn with #277 thread on top and 207 in the bobbin.. You may find it to be less than 3/8 inch. #277 thread requires a lot more upper spring tension to pull the knots up into veg-tan leather than thinner threads. That's why the tension springs on the 441 clones are about twice the thickness as springs on upholstery class machines, which are already heavier than the beehive springs on garment sewing machines. Structurally, there is no benefit to using heavier thread on top because the thinner bobbin thread will be the first to give under stress.

No matter how it is powered, that is and always will be a Singer 29k-something patch machine. I can't tell if it has a small or large bobbin. The model number will reveal that. Singer patchers max out at 1/4 inch under the claw foot. You can sometimes coax them into sewing 5/16", but the foot will really claw up the top grain. Most small bobbin patchers max out with #69 bonded thread. You can use #92 if the machine is tight enough to pull the thread ahead for another stitch. The stitch length varies with the thickness under the foot. A factory condition 29k can sew up to 5 stitches per inch, at 1/8 inch, declining as the work gets thicker. A worn out feed mechanism will be lucky to get 7 or 8 per inch. This would be a great machine for sewing patches onto Bikers' vests and jackets, especially if it is motorized (you can guide the work with both hands). Stitch length won't matter if you use the same color thread as the embroidered edges. It can also sew shoe and boot uppers and small zippers, plus purse strap tabs.

Never back wheel with thread in the needle. You may get a nasty jam around the shuttle and bobbin case. Spin the work 180 degrees to backstitch. A Singer 66 is a garment mending machine. It can only sew about 1/8 inch of soft leather with no more than #69 bonded thread, using a #18 needle.

You may not know this, but, the Cobra 441 machines have optional flat, slotted throat plates for use with soft or flimsy materials. You need to remove the feed dog to install that plate, so the machines becomes double feed. But, it is cheaper than a second dedicated walking foot machine, until you really need one. There is also a flat bed table attachment for the Cobra Class 4.

While a Cobra 26 can sew 1/4 inch of veg-tan leather, it only does so with #138 thread (or possibly 207 on top and 138 in the bobbin). Either way, that thread is inadequate for securing a weapon in a working holster. The reason is that #138 thread has a breaking strength of 22 pounds per stitch. It is easy to put more stress on the stitches holding a holster together than 22 pounds, especially during a struggle, or panic situation. Ideally, each stitch should have twice the strength, calling for #277 thread.

What 29 sub-model is it? Is it mounted on the matching cast iron treadle base, or is it motorized on a pedestal table, or is it just the head? I ask because it takes two hands to guide the work, leaving just your feet to operate the treadle, or an electronic speed controller if it has been motorized. I use my 29k71 to sew patches over pockets on Bikers' vests and to sew shoe uppers and purse strap tabs. I wouldn't think about using a patcher to sew a straight line longer than a few inches unless you first gouge a stitching channel into the top layer. Keeping the claw foot from moving sideways can be done by tightening a thumbscrew that goes into the front of the revolving head housing. You really should not waste your time with a patcher unless you do shoe or purse repairs or sewing for Bikers. The bobbins are tiny and the thread handling capacity usually maxes out at T90. Finally, the maximum stitch length of a like new machine is only 5 stitches per inch, into 8 ounces of leather. The thicker the work, the shorter the stitches. As these machines wear out the stitch length gets smaller and smaller. I have encountered patchers that could only sew 8 per inch into thin shoe upper leather.

It could be that the needlebar rock frame is binding in the right angle metal bracket that keeps it inline, at the bottom of the head. Open the faceplate, loosen the bracket screws and see if the motion cleans up. If so, find the position of least slack without binding and tighten it down.

A couple of small close-up photos are better than a thousand words. Show us photos of your needle area and of the top thread path. Experienced sewers can spot an incorrect path in moments. Include the work piece you are trying to sew, where the knots are on top. If the machine shipped with a pack of needles, tell us the size that is in the machine. It is also embedded into the top shank of each needle.

Once the lifting chain has been connected with the absolute minimum amount of slack that allows the outer foot to stop firmly on the standard throat plate (whew!), pushing all the way down with the ball of your foot should lift both feet so that about 1 inch clearance exists under them. Do this with the needle at its highest point! The machine's specs calls for 1 1/8 inches of clearance at full lift. If you can get one full inch, grab a beer and call it a day. The tighter the pressure spring, the harder it gets to raise the feet that high.

On 441 type machines the hand lift lever does not lift anywhere near as high as the foot lift pedal does. Mind you I have never tried to change that on my Cowboy or my buddy's Cobra. My shop is closed until Monday, so I will try to remember to ask a dealer if this is doable.

Matt; If you really want to dive into thread measuring systems, there's a good read on Superior Thread's website, under the education section topic: Understanding Thread Weight.

There is no Ticket 0 I know about. Maybe this is Juki/Japanese numbering. But, by looking at the maximum listed needle size we can extrapolate the matching thread. A #280 needle would be used to sew with #415 thread, top and bottom, or 6 or 7 cord linen thread (normally, a #27/250 needle is used for these thread sizes).

Ideally, the owner of the storage unit, or store that is selling the machines should place an ad for the equipment, along with photos, prices and location. In your case, you are one of their customers who wants to share the bargains with LWN members. The photos and estimated or asking prices and exact location should go into a new topic you start under the Marketplace forum I linked to previously. Just click on the bold underlined words to go to that section of LWN. Start a new topic. Show the phone number of the owner of the equipment unless you are hired to act as his/her agent. You will need to use a photo editor to reduce the dimensions, thus file sizes of your photos. I recommend trying to change your camera's resolution to the lowest file size possible. When I shot with a Canon digital camera the best size for web pages was 800 x 600 pixels. My smart phone doesn't go that small, so I use FastStone Photo Resizer to make my photos more web page friendly. It doesn't take too much work to get a 3 Mb camera .jpg down to 300 Kb or less.

I think that those # designations may correspond to "Tkt" numbers, as shown on this thread and needles chart.

Is the thread passing around and into the check spring and is the spring's range of motion holding it taut until the needle pierces the material?

Have you read the entire description of what is for sale? The table is NOT included and the machine breaks thread.That means you will need to buy a table with the proper size cutout, hinges and rubber mounts, a K or H legs frame with a floor pedal and linkage, a thread stand, flex lamp, bobbin winder, machine tilt back peg, v-belt and drawer. All this may cost as much as the head itself. And, you may have trouble controlling a clu6tch motor at slow leather sewing speeds. This will not be a good first industrial sewing machine purchase. You will probably need to at least double your budget unless a super deal falls out of the sky.

I think it is a great machine sewing awnings, tarps, sails and Bimini and seat covers. All of the above are either water repellent cloth or vinyl. The machine is not tough enough to sew anything stronger than seat or chap leather. The standard feet have teeth on the bottom to claw the work through. These teeth leave permanent marks in any type of leather that has a memory (veg-tan, bridle, retan, etc). They do sell smooth bottom feet as an aftermarket option. The design is such that 1/4 inch is the most thickness you can sew and advance under the alternating feet. Further, you would need to upgrade to the Monster II flywheel in order to penetrate leather and maintain a steady slow speed. By the time you have upgraded the machine, you'll have $1000 invested in it. For the same money, plus gas or shipping, you can order a brand spanking new Consew P1206RB compound feed, walking foot, large bobbin, leather sewing mo-sheen.

The Singer 31-15 is a garment sewing machine. It uses the typical system DBx1 garment needles. The fairly thin needle bar is held in time to the hook by a single set screw. It takes very little force to cause the bar to move up, throwing the timing out. This causes skipped stitches. A bent or burred needle also causes skipped stitches. In case you missed my comment about this being a tailoring machine, it is designed to sew cloth garments. It can sew soft chrome tanned leather using a roller foot. It is not built to withstand the pounding caused by veg-tan leather. Further, these machines are not equipped with strong enough springs and take-up cranks for #138 thread sewn into hard temper leather.

4 x 5 oz = 20 ounces = 3/8 inch. This is the very top limit your machine "may" be able to sew. Even if your machine can sew 20 ounces of veg-tan leather, #138 thread is inadequate for any serious hand gun holster. It is too easy to break the knots during a struggle or panic draw. I would not sew a gun holster with less than #277 thread, top and bottom unless it was just for show, not go. Then #207, top and bottom would be minimally effective. If you choose to ignore this advice and sell holsters sewn with #138 thread, hire a lawyer, just in case something happens because the thread let go.

I have bought them off eBay in various sizes in leather point. Here is just one source of System 190 leather point needles.

This is my "Sticky" topic about the type of sewing machine you need to sew leather. It stays put on the entry page to this section the "Leather Sewing Machines" section of the Leatherworker.net forum. All sticky topics remain above all standard topics that float up and down with activity or inactivity.