Important things I found out about the Singer 15K110

The Singer 15K110, or the 15-110, is not a well documented sewing machine, in fact finding a user manual, adjusters manual etc seems to be impossible unless you have a good grasp of obscure internet technology! Likewise, no videos exist which cover the 15K110 except in very generic terms. Just so that you know, there was a copy of the user manual on a website called Needlebar.org, which appears to no longer exist, but ghosts and breadcrumbs exist. I briefly had a link that worked, but it stopped working a few days ago. In the end I used a site called “Wayback Machine” which allows you to look at previous versions of web pages, and I found the most recent version of the manual here https://web.archive.org/web/20230531215445/http://needlebar.org/main/15chart/110/index.html

Unfortunately parts 2,3 and 4 have no images, but part 1 is the bit I needed.

I read a lot of stuff about this machine, most of it very generic, but I gleaned that the 110 has a subtle difference to the previous version, that it threads the needle from left to right, not right to left.

All this did was confuse me while I was rebuilding the machine after stripping and cleaning it. It took me three days of terrible stitches, many attempts at taking various parts apart, adjusting needle height, needle and hook timing, trying threading the upper thread from both sides, threading the bobbin from two sides, adjusting top and bottom tension.

Eventually I realized I was having too much difficulty just threading the needle.

The manual above confirmed that I had to thread from left to right, but the groove was on the wrong side of the needle. The flat of the needle was in the groove on the needle bar, but the flat of the needle was facing left! Something fundamental was wrong.

While I was building the machine, I remembered that the needle bar did not have a flat where the needle height adjuster screw clamps the needle bar, unlike other machines I have built. It dawned on me that the bar had been inserted into the machine turned 180 degrees. It was adjusted correctly, it was timed correctly, but the needle was facing the wrong way!

It took two minutes to release the screws, turn the bar round and tighten it up again.

The needle goes in with the flat facing to the right, the thread goes in from left to right, and when the bobbin is inserted in the bobbin carrier, the bobbin should rotate anti clockwise when viewed from the left of the machine, as described in the manual above.

Net result, the machine stitches with no dropped stitches both forward and in reverse. A bit of work is needed on the tension, but this progress is a big relief. After all this machine cost me $30, has perfect RAF decals and shiny paint and metal bits, and I really wanted it to work.

Postscript.

It’s all very complicated, left to right feed, 1 o’clock or 11 o’clock bobbin holders. Early machines went one way, later machines went the other, then much later machines went back to the original way, possibly because of the success of the HA-1 clones from Japan and other countries based on early machines. The 15k110 appears to use features developed for HA-1 clones, so is a sort of clone of a clone. HA-1 generic manual which covers the 15K110 quite well can be found here https://ismacs.net/singer_sewing_machine_company/manuals/ha-1-ib-wgh-instruction-manual.pdf