Tejas

Here is a link to an animated knot web site. There are other sites. https://www.animatedknots.com

The best copy of the manual I've found is on Gregg's Keysew web site. http://keysew.com/Webpages/DemoImages/Juki_LU-563_Instruction_Keyfooter.pdf

I'm sure somebody who can help will respond soon. Assuming you already have a user manual, attached is the service manual that might be helpful. JUKI_DNU-1541_SERVICE_MANUAL.pdf

Here is an old thread with links to US Army sewing machine operation manuals: http://leatherworker.net/forum/topic/22758-us-army-sewing-machine-operation-manuals/

Your lub-pot is opaque, and thread-path cannot be seen. I've only used the Sailrite lub-pot and have not had that problem. The Sailrite thread-path is on the bottom of the pot, and only a small amount of lub in the pot is necessary. The reservoir is transparent, and the lub-level can be seen for replenishment. There is also a screw-on cap, so oil is unlikely to slosh out.

Here is a link on penetrating oils, including WD40. You might want to test a small spot for aggressiveness before applying liberally. http://www.practicalmachinist.com/vb/general/ot-penetrating-oil-196347/

I have no actual experience using acetone for such a project, but you probably already know to google the dangers of acetone first.

I use a cutting pad with a grid pattern and also several different Omnigrid rulers, and recommend both.

Sailrite sells a thread lubricator for about $20. https://www.sailrite.com/Magnetic-Thread-Lubricator

Here is another (I didn't recall it was from this forum): http://leatherworker.net/forum/topic/54776-4-slot-bifold-template-directions/

Might look at the pattern in the following link: http://leatherworker.net/forum/topic/59038-minimalist-tri-fold-wallet-uploaded/

Link to a user manual is in this thread: http://leatherworker.net/forum/topic/75566-mitsubishi-du-105/ I have a pdf of the parts manual Mitsubish DU-105_ManyOthers Parts Manual.pdf

Ditto on Gregg and his mother at Keystone from another, albeit remote, customer.

Had to look this up, and on youtube there is a video on making a zipper jig from a fork. Not practical for production, but probably good enough for me.

lu1500n.pdf

I think that the -08 is the zig zag width in mm. Machine models came in 4.5, 6, 8 and 12 mm. The cam reader is an option, and if present is mounted on the back of the machine. Sail makers prefer a machine with a cam reader, and use cams for three-point two step and four-point three step zig zag. If you decide to get the machine, I have an adjustment manual that I could scan and post. I also have a copy of the parts manual that is too large to post but could email.

Many of your questions might be answered by searching the forums. I think searching via google is more productive. For example in google type: juki 1508 vs 1541 site:leatherworker.net

Might be an overkill, but in google try: sailboat stainless steel strap tang

Link to Instruction Manual. https://www.manualslib.com/download/917750/Juki-Ls-341n.html

Here is a link to a very good pdf manual for the Juki 562 / 563. http://keysew.com/Webpages/DemoImages/Juki_LU-563_Instruction_Keyfooter.pdf

Attached is a pdf copied from Keystone six years ago. Might still be there. Groz-Beckert_Needles_for_leather.pdf

Probably easy to make. The presser foot spacers I mentioned came as a set in various thicknesses. However, the seller's link is no longer valid.

Here is a thread on similar subject. http://leatherworker.net/forum/topic/62249-sewing-through-thick-spots-with-juki-1541s/

For sewing over difficult changes in layers, I use a jean-a-ma-jig or presser-foot spacers, aka hump-jumpers. Sew up to the hump, and with the needle buried raise the foot and insert the spacer behind the needle and manually sew up onto the hump. Sew across the hump. To sew off of the hump, while still on the hump raise the foot with the needle buried, insert the spacer in front of the needle and sew over the drop-off before removing the spacer. Manually climb the hump, over short humps and off the hump. https://www.amazon.com/Dritz-Jean-Majig-Sewing-Product/dp/B005572NPS/ref=sr_1_2?s=arts-crafts&ie=UTF8&qid=1506068841&sr=1-2&keywords=jean-a-ma-jig

This thread might help. http://leatherworker.net/forum/topic/56568-seiko-ch-8b-or-singer-45b8bc/