Constabulary

yeah - that can happen and often owners do not what to do and sell the machine as broke. This is what I found on my 107w1 between bobbin case and hook when I received it. The thread and oil have built up to a really compact piece. There were 4 or 5 colors of thread in this thread "cookie". They just did not care about the machine until the bitter end (all of a sudden, of course) and then did not know what to do. Machine cost me 1€ + shipping back then Conclusion - better know your machine and be able to help your self.

Your dealer is right. You cannot use singe needle piping foot set on a double needle machine! You can try to modify a foot set but that requires cutting and welding / brazing. Maybe a cheap drop feed machine will work better. Like Juki 127, 555 or a Singer 31K, 331K, 95K, 96K or the like. Accessories are rather cheap for these machine. You sometimes can buy industrial plain drop feed machines for a bargain but depends on your sewing machine market... Note the list of machines in the description: https://www.ebay.com/itm/143446313333

45K´s sometimes have round belt groves and sometime V groves (newer machines rather have V groves) and yes considering the size of the machine the grooves seem to be quite narrow sometimes. Mine has V groves and I´m using a 10mm 10/Z belt (metric world) or X10 (toothed) belts - no problems. Yes the belts seem to bee a bit too wide but thats not really an issue. So it really depends on your machine pulley. https://www.zahnriemen24.de/a/40051-keilriemen-z-10 https://www.zahnriemen24.de/a/40059-keilriemen-x10 Alternatively on some of my machines I´m using green PU round belts with rough surface in 8mm like this: https://www.ebay.de/itm/133659334890

What domestic machine costs 4000? New computerized or vintage? It´s one thing that someone is asking that kind of money for what ever machine the other thing is finding someone who is willing (or able) to pay that money. Often (vintage) domestic machines are more a collectible rather than a machine people are actually using. Of course there are a lot of shades of grey between collecting and using but IMO most domestic machines are overpriced. But vintage industrial machine are sometimes way overpriced too especially on Ebay.com.

@Jholden0 maybe a longer bottom bushing will do the job too. I just noticed the later model 51w seems to have a bottom bushing only so maybe a longer one will work w/o installing a top bushing. I only can guess but looks like a good solution w/o drilling and gluing in a top bushing. Of course diameter of old and new bushing have to match. See below thread:

Yours appears to be the 2nd model of the 51w and to me it looks like it has a smaller diameter needle bar than the 1st model (which I own). Looks like you have a fairly long bottom bushing but no top bushing (due to short needle bar). I only can judge from pictures as I never have touched a 2nd model 51w. I guess the NB on your 51w has a 6.35mm diameter. Therefore you could use a Singer 107w / 143w or Singer 111w needle bar. Take a measure on your 226R - I assume it has a needle bar with the same diameter as the 51w shown. If that's the case it will be an easy task. You probably have to shorten the new NB.

IMO oil the open gears - grease tends to collect dust, lint, dirt (broken needle tips sometimes) more than oil. When you apply new oil it can wash off some dirt, lint... thats what the oil drip pan is for. No matter what clean the machine regularly. I only use grease or sticky synthetic lubricant in capsuled gear boxes. But as always opinions are different.

https://www.ebay.com/sch/hotheart10/m.html?_nkw=&_armrs=1&_ipg=&_from=

You have no needle plate installed - never run your machine without needle plate. Install needle plate and make sure the small tab #4 sits in the gap in the needle plate as show in the encircled picture.

Misread - forget what I wrote - looks like you want to ship a machine + table...

Instructions are always welcome - please share!

I use heavy double wave carton and on the in inside to each side min. 1.5" stick Styrofoam plates (the thicker the better). Fill all (really ALL) free spaces with cut pieces of the Styrofoam plates the way that the machine cannot move inside the package. I prefer UPS - never had issues with them.

Please post pictures and a video of your own machine so we can evaluate the issue better. Are you sure #4 is in the notch of the needle plate as shown in the encircled picture? For adjusting the bobbin case opener loosen #2 adjust #1 the way thread keeps not hanging between #1 and #3 and in the gap between #4 and the needle plate (encircled picture) and tighten #2 again. But that should be mentioned in the manual I think.

Bitten by the buck - there is no cure Very good choice! You will have no problems finding parts!

ouuuh - indeed a very special color! Does it glow in the dark? I wouldn´t want to look at it all day but it of course it is a personal choice. I´m sure folks here would have crucified me for "destroying" the original floral decals on my machine (and maybe for other things). But I just do not like it though it looks good but its not what I like to look at when working with the machine. Personal choice... But please don´t put Hello Kitty or My little Pony stickers on your machine **kidding**

you need 380/400Volts and an air compressor to run this machine with it´s "Bells & Whistles" - keep that in mind.

Michiel - his picture shows the 212 not the 239. 239 is a nice machine when properly set up. Very similar tot he Singer 111G156 presser feet are the same as for the 111 series also the bobbins an several other parts. If it is a 239-531 it even has a large hook (bobbin size like Adler 167)

most likely for sewing shoe upper or for decorative stitching. I haven´t sewn seat covers but a flat bed machine would probably the better choice for this work.

looks like a Pfaff 335 clone - manuals can be found online.

Can´t really help but maybe a filter sack from a wood working dust collector is an idea. https://www.harborfreight.com/13-gallon-industrial-portable-dust-collector-31810.html https://www.harborfreight.com/2-hp-industrial-5-micron-dust-collector-97869.html

I have two of these stainless steel burners for different purposes. https://www.ebay.com/itm/131038097614 You can throw in some neodymium magnets to hold them in place (require iron surface of some kind)

Are you aware that the UK Gov. wants EU supplier to collect taxes for the UK Gov. for orders below 135 GBP and transfer the VAT to the UK Gov. - that requires work a tax consultant meaning it costs money and a 3€ order is just not worth the trouble. If you run a business in the UK - would you collect VAT for the Italian, French or German Government and then transfer it to them - I doubt so. But the UK Gov. wants just that! The UK for sure are not a public enemy. But the UK decided to leave the EU not the other way around. Brexit makes it complicated in both directions - we all suffer from that! @GeorgePepper pretty much hit the nail. It´s just too complicated - tax + paperwork - and not worth the trouble especially for low value orders. I also no longer can place orders in the UK - I tried 3 Co´s none will deliver to the EU - including my long time supplier College Sewing. I really would love to spend my money in the UK - I just can´t - because of BREXIT. I wish Brexit never happened and I´m sure if the people and businesses in the UK had proper information on how BREXIT will impact their life most people would have not voted for leave / more would have voted for remain.

Remove the needle plate (and maybe feed dog). Remove the small screw shown the picture. Swing the curved piece by side. Grab the center post of the bobbin case with your fingers and rotate it until it comes out. Then in the center of the hook you see a screw. This screw is holding the hook on the hook drive shaft so remove it. When the screw is out you can pull out the hook (but both could be tight because of gummed oil). The sideways play on the top shaft most likely is because the hand wheel is a little bit too far right on the shaft. Loosen the two set screws on the hand wheel. Then you are able to carefully tighten the screw on the right end of the shaft to minimize the sideways play. Do not make it too tight. Then tighten the 2 set screws again.

the cutout in the needle in which the feed dog moves can limit the stitch length too. There were 45K needle plates with shorter cutouts and smaller feed dogs. maybe you can post some pictures of your machine and how it is set up.

As you figured you don´t need a double needle machine but it is faster and more accurate (depending on your skills) as you see in the sneak peek picture of that video the seam stitches are not 100% equal (this may matter or not depends on your or your customers expectations.)