Tejas

Here is a Army manual starting on page 113 with detailed instructions for disassembly, but not much help for assembly. I haven't found a pdf, but hardcopy can (or at least could) be purchased via ebay. https://archive.org/stream/TM10-3530-202-24#page/n1/mode/2up

Chapter 3 of this manual might be helpful. http://militarynewbie.com/wp-content/uploads/2013/11/NAVEDTRA-14217-Aircrew-Survival-Equipmentman-1-C.pdf

A compound walking-foot machine might be more essential than you have experienced so far. I sew mostly marine canvas and when sewing canvas, the number of layers can mount up quickly. Simply sewing a double-fold hem over a semi-flat felled seam is nine layers. Sewing a double-fold hem over a flat felled seam is 12 layers. Doulble-hems at a corner also result in nine-layers but can be mitigated to fewer layers by mitering the corner. Add some webbing, and layers and thickness can increase quickly. Needle-feed also helps mitigate the tendency of lower-layers of material to feed faster than upper-layers with drop-feed machines.

I think that the machine is a Cordes. https://www.youtube.com/watch?v=bvCpv6kllY8

I thought that the Nakajima 280 later became the Juki 241. I don't know if it helps, but attached is a manual for the two machines. Juki-241H-Nakajima-280L.pdf

I'm only familiar with two models -- 1541 and 1541S. The S model has a safety clutch, and while retails for only $100 more and is worth the expense. As for retail price and other information, the following link might be helpful. http://store.keysew.com/sewing-machines/juki-sewing Here are a few suggestions for buying used. When buying a used machine, try to find a manual online, or at least a few pictures. Sometimes machines are not even complete. If a manual cannot be found, try "how to thread [machine make and model]" on google. Take scissors, small screw drivers, thread and sample fabrics, needles, flashlight and of course the manual. Using different colored thread for needle thread and bobbin thread and different from the material color helps to be able to see the stitches and tension. First, ask the seller to demonstrate the machine if they can. Then with a flashlight look top, bottom and underneath at overall condition and especially for rust. Look at the slots in screws and the sides of bolt-heads for evidence of heavy-handed maintenance. Try to wiggle the needle bar by hand front to back and sideways. It should not move. The machine should be tight, but operated easily by turning the handwheel. The handwheel might have a little play but the feed and needle bar should not. The electrical connection on older machines can be a problem. Wind a bobbin with your thread and using your top thread, sew with your sample material. Verify that the stitches look OK both top and bottom. To test stitch length, set the stitch length, un-tread the needle and with the hand-wheel operate the machine sewing forward “sewing” a piece of light cardboard or heavy paper for a few inches. Then with the hand-wheel operate the machine in reverse. The needle holes in reverse should perfectly match the holes going forward. Remove the cardboard and measure the actual stitch-length versus the setting. Do that for various stitch lengths. If applicable, repeat for various zig zag widths. Beware that oil can become very viscous and interfere with the operation of a machine that has been unused for a very long time. In a severe case, the machine might need to be immersed in solvent to dissolve thickened oil. Attached is a Juki 1541 service manual for all models. JUKI_DNU-1541-S_SERVICE_MANUAL.pdf

I think you are looking for a technique for aesthetics, so I'm not sure this helps, but as for ending at a particular point, I sew to one less stitch from the ending point and with the needle up use the reverse level to shorten the last stitch to end as close as I can to to the desired point.

Here is a file that seems about the same as troubleshooting2 but in a different format. sewing_troubleshooting_chart.pdf

I got a custom binder from Keysew, and am quite pleased with it. http://store.keysew.com/sewing-parts-and-accessories/460-custom-angle-binder

As for how to install the zipper slides, the image in link below was taken from a The Green Pepper pattern. http://i742.photobucket.com/albums/xx61/Tejasdave/Double Pull Zipper/Dual Pull Zipper Scaled_zpsrx9cympk.jpeg

As mentioned in a previous post, I buy zippers from Sailrite, always YKK zippers, including finished zippers, and continuous zippers, zipper sliders and zipper stops. Making double pull zippers from continuous zippers is not difficult. Sailrite has zipper videos than might be helpful, and that should be applicable for continuous zippers acquired elsewhere. http://www.sailrite.com/type/Projects--AND--Tips?keywords=zipper http://www.sailrite.com/Zipper-All-Questions-Answered-about-Zippers-Streaming-Video I've not tried it, but apparently a finished zipper can be converted into a double pull zipper. https://justinelimpusparish.wordpress.com/2010/11/01/making-a-double-head-zipper/

I buy zippers from Sailrite. http://www.sailrite.com/Notions/Zipper

As for changing the bobbin without removing the bobbin, the machine was a Consew 206 RB, also using a right-angle binder at the time -- pulled out the old bobbin, put in a full bobbin, and continued sewing. I don't recall, but I think I later tied-off the threads on the underside.

When I got my machine I decided upon the 1508 because I had learned on a top-load bobbin machine. Had I learned on a bottom-load machine, I might have decided upon the 1541. Prior to buying the 1508, I had sewed for two-weeks on a bottom-load machine, and the benefit of less requirement to hold the thread was not sufficient enough. An advantage of bottom-load -- mentioned by mixmkr -- the ability to change the bobbin without removing the material was not compelling to me. My other machine is a bottom-load machine, and I still prefer top-load, but then I sew only occasionally.

I frequently use PTFE Tenara V-92 equivalent thread, threaded as you describe as "originally threaded" but with an additional loop -- four-hole guide vs three-hole -- with no problems on a Juki 1508. However, the 1508 thread-path cascades through two tension disks.

The Juki 1500N Engineer's Manual lists the various models' specifications. Gregg characterizes the differences: "As for the H model of the LU-1508N...this machine has a heavier 'flywheel' or handwheel. It's about six pounds, the standard is is about one pound. This helps with starting torque starting the run and getting the machine turning over. The H model also has a heavy hook that will allow a larger needle and thread to be used. That's it, part for part, really. I don't really know why people would think this is a much heavier capacity machine than a standard walking foot is capable of. It's not." In the following thread: http://leatherworker.net/forum/topic/66067-machine-choice-heavier-than-a-juki-1541s/ LU-1500N Engineer's Manual 2002.pdf

As for lack of reverse, here are four ways to mitigate lack of reverse for back-tack. At the start and end of a run:1. Turn the material end for end and sew over the seam. The result is the same as a back-tack but not always practical for large projects.2. Sew to the end of the run. Lift the foot slightly pull the material about 1/2 inch toward you, drop the foot and sew over the seam.3. At each end of the run, leave several inches of thread. Tug the thread on the under-side and pull the top-thread through. Tie off the two threads with a surgeon's knot. A square knot can be used, but a surgeon's knot is more secure.4. Same as above, but leave even longer threads. Do not pull through. Thread a needle on each and sew several stitches through the same holes in the seam. A hassle, but the resulting back-tack should be more secure than a machine back-tack.There are situations where reverse can very useful, such a sewing around for some reason fairly far inboard from the edge of the material, such as a ppatch, but that can also be done by a combination of maneuvers similar to and including the manual back-tack described above. Another use is the ability to position the needle for a single, shorter stitch, such as at the end of a run. I started with a Singer 111W155 and really liked it.

Attached is a copy of the service manual. For some reason the cover page with the document number is near the end of the pdf. Juki LS-1340&42 Servcie Manual.pdf

Assuming that you have a user manual, attached is a service manual. JUKI_DNU-1541-S_SERVICE_MANUAL.pdf

PM sent.

Here's a link to the thread lubricator I use. http://www.sailrite.com/Magnetic-Thread-Lubricator

Here are links to how to measure, and reliably set, tension with a spring gauge. http://sew24.blogspot.com/2012/11/how-to-measure-thread-tension-with.html http://jukiindia.com/Item-List/Adjustment_Procedue.pdf

The problem might be lifting the foot too high, opening the tension disks. You might try lifting the foot only high enough to turn the material. The needle should be buried and just on its way up.

I use thread lub when sewing using seam tape with the hope that the lub might mitigate gumming up the needle. I really don't know if it helps or not, but I think that it does.

There was a Nakajima 280L that I think was the same as the Juki 241H after Juki bought Nakajima.