Uwe

Looks like the machine is in nice condition and the Variostop is a good Efka motor/controller. The pedals indicate foot operated presser foot lift and reverse. I think this may be a model shared by Adler and Singer. It looks just like an Adler 220 and the "A" in 144A305 may well indicate a re-badged Adler. You can look for Adler 220 documentation and compare. The Adler 220 brochure (2205073.pdf) has some specs. @Gregg From Keystone Sewing has a double needle version of this machine on his website (http://store.keysew.com/catalog/product/1bb153606d494c4a9b634c398c3a8095) so he may know more about it.

It looks like you can run the machine on single phase 220V, according to the Durkopp 291 installation manual.

I don't see a manual foot lift lever either.

Well, the Toronto area should be good for a while with fancy vintage Durkopp machines. You can start a local Durkopp 291 support group! Some of these fancy full function packages are all-or-nothing propositions. Either it works or it doesn't. There's often not a whole lot of middle ground. Buy two or three. Trying to convert the head to a plain manual setup may not yield satisfactory results. If everything works as it should, they're a joy to use. One downside to super cheap, fancy vintage machines is that everything else afterward will seem super expensive. A decent rotary 3-phase converter and a quiet air compressor will cost considerably more than the machine, but the whole setup may be well worth it.

If you can live without reverse, my Singer 153W102 may be a candidate. I just made a posting for it:

I have a Singer 153W102 bottom+needle feed cylinder arm sewing machine is for sale. Just the head, no table or motor. Price is $450 if you pick it up near Detroit, Michigan. Pickup is preferred, but this head could be shipped in a box. The head alone weighs 65 lbs. Packaged well, the shipping weight would be close to 90 lbs. Dimensions would be around 16x20x24 for the outer box. Packaging takes time and new nested cardboard boxes and foam-in-place pouches are not cheap. Add $50 for packing. Shipping itself runs about $1.00-$1.50 per pound within the U.S. depending on carrier. I replaced the timing belt and made the stitch length mechanism work again. It won't win any beauty pageants, but It's adjusted well and makes a very nice stitch. Here's a demo video of this machine sewing heavy canvas and vinyl material: Below are a few pictures:

google

Please upload some photos of the machine here. The original photos are being held hostage in Photobucket hell.

I'd try some 126x3 needles, which apparently are the same as 126x9, according to this Groz-Beckert needle pack: The 126x3 needles are available online: http://www.thethreadexchange.com/miva/merchant.mvc?Screen=CTGY&Category_Code=NDL-126x3 Our trusty banner vendors may carry them, too.

I needed to figure out how to make a CAD animation and this seemed like a good practice piece:

Clever solution. I suppose a second picture that shows how these pieces are nested and actually fit on the shaft would allow people to reconstruct what you did. I'm sure it's all clear and obvious in your mind, but that one picture doesn't really illustrate the story well.

This really is the wrong forum. There must be others out there better suited. It appears you're using the wrong machine to sew Batiste (had to look that one up ) The Juki DDL-553 is designed for medium to heavy weight fabrics, which is why it works fine on denim and similar fabrics. You need a machine designed to handle delicate fabrics. The average home sewing machine is likely better suited than the Juki DDL-553. Even with suitable machines, people apparently sandwich very fine fabrics between tissue paper to give the material some stability. Then tear off the tissue paper after sewing the seam. (https://www.youtube.com/watch?v=uDADCZ20ce4 )

There are several subclasses of the Adler 205 design with different variations on the feed mechanism. They come in top+bottom+needle feed (compound/unison), top+bottom feed, bottom+needle feed, and some other variations. The Adler 204/205 model brochure leaflets show the different Adler 205 models available at one time. Here's a slightly hokey video that shows non-unison feed Adler 205 designs stitching some non-trivial seams:

It looks to me like your hook timing is about "five minutes" too late. On machines with this vertical axis hook design, the hook timing criteria can be generalized like this: When the needle is in the bottom dead center (BDC) position, the tip of the hook needs to be at the 7 o'clock position. I superimposed a still frame of your video with a clock face to illustrate the concept. Your hook tip represents the Minute hand on that clock. On your machine the hook is about five minutes too late, i.e. hook tip points at 6 o'clock instead of at 7 o'clock when the needle is at BDC. I recommend advancing the hook timing clock-wise by "five minutes." After advancing the hook, you may also have to adjust needle bar height up a little to make the hook tip pass the needle near the lower third of the scarf. I think you will find that the other issues like thread snapping around the hook, then catching on the release finger, then snagging on the rectangular hook gib below will all improve as a result of the hook advancement.

That tension screw post on your machine looks quite bent in that first photo - it must have absorbed a pretty good whack at some point. In case the post does not cooperate with a simple repair, a new tension unit is not expensive and easy to install. If you decide to replace the tension unit, I'd recommend getting a nice new OEM tension unit made for a Juki LU-562 or something similar. There are many compatible tension units out there. The super cheap Ebay tension units are cheap for a reason in my experience - I have several that I don't even want to install on a machine. Even a very nice OEM tension unit is not expensive. @Gregg From Keystone Sewing can hook you up, I'm sure. Luckily, installing a new tension unit is a very easy task on these machines. It may take you longer to find a screwdriver than to actually install the new tension unit. Here's a video I made just now that shows how to install a new tension unit in under two minutes. Here's another video I made some time ago that goes into more detail about the check spring adjustment:

@Rustic, you can get the ball rolling by telling us why YOU think the machines you listed are even candidates for what YOU want to sew. The machines you list have been discussed dozens of times before. You have a better chance of getting a meaningful response if you give us some background, show us your homework, tell us what's important to you and what your budget is, and then ask specific questions. This may sound like work, but it's no less work on our end.

19/32" drills and 1/2" bore pulleys are readily available.

Even the cheapest plastic caliper you can buy on Amazon for $2.74 (http://a.co/475FoBc) is more accurate than your guessing game. Put some value on your time (and ours) and you'll be able to justify a decent caliper very soon. Once you have one you'll use it a lot.

The video below (starting around the 1:08 mark) is a little corny but shows a setup that looks promising for sewing thick leather extremely close to obstacles. I don't even know what subclass that Adler 205 style machine is, but that tall, skinny foot immediately behind the needle sure feeds that thick leather well and generally stays out of the way. The special throat plate also has cutouts that allow obstacles on the underside very close to the needle. I can see that combo working well with T-style buckles. Unfortunately, I have no idea where you can find such a machine, sorry.

The bobbin case opener finger on the machine in the video above is not adjusted properly and does not perform the task it's supposed to. That's why the thread snags on the tab. I made a video recently for a different topic related to bind conditions using my Juki LS-341(different machine, but same hook and bobbin case opener functionality.) The first half of my video shows how that bobbin case opener finger should be adjusted and how it moves the tab. Perhaps it can clarify a few things. The way you adjust the bobbin case opener finger is a little different on a Juki LU-563, but the same concept applies. Here's a video from my archive that shows a 563 class machine after I made some adjustments (unrelated to the bobbin case opener.,) It shows how the finger pulls back the bobbin case from a different angle.

I just edited my earlier post to add a demo video on how I use my iPhone magnifier/loupe function. Of course an old school magnifier would probably work just as well:

I can't come there an time your machine, sorry! But I can offer some tips on making it easier with not-so-perfect eyesight: 1. Use your (or somebody else's) iPhone as a magnifier loupe (https://9to5mac.com/2016/09/26/how-to-use-ios-10-magnifier-magnifying-glass-iphone/) . Android phones may have this feature, too. 2. Put a piece of paper behind the hook to see the gap between needle and hook better. Here's a video of my setup when I do very detailed adjustments: 3. Use the needle guard to keep the needle a safe distance away from the hook:

You could probably simply ignore the crack, too. If the machine sews fine, just put it in a proper, very strong table top and use it. That tiny crack at the 10" mark on your ruler should not affect functionality. Any hot welding fix attempts may just make matters worse. Properly supporting the machine may be all you need to do. Most tables only support the machine at the corners, but you can machine an edge that supports the machine along the "lip" instead of just the corners. The most likely cause of that crack is a bowing table top that only supported the machine at the very left and right edge. Many cheap industrial table tops are simply too weak to support the sewing machine without bowing in the middle. That big hole in the middle weakens the table top considerably. Especially particle board table tops are only straight for short while after you cut a big hole in them and drop 70 lbs of weight on them repeatedly. If the machine is supported only at the ends and you let it drop down often enough, a metal fatigue crack will develop in the unsupported middle on the underside. Fixing the crack without fixing the table top will only buy you a little time. Putting the machine in a proper, very sturdy table top, may keep the crack from getting worse and if the machine sews fine as it is, there may be no need to "fix" the crack. I had a machine with a similar crack in the bottom ridge that worked just fine. I built a new, straight, and sturdy table top for it (two layers of 3/4" plywood glued and screwed together). It's been performing well in a production environment going on two years now.

If, after watching that last video above, you can't figure out how to remove or install that thread tension unit, then my advice is to step away from the machine and let somebody else perform maintenance tasks.

This video shows, among other things, how to remove the tension unit and how the tension release pin works: