Constabulary

Thats actually a restored Adler 30-15 (short arm) but it shares several parts with the Singer 29K. I can post a full view tomorrow.

Wiz, I think the bobbin thread belongs there. Thats what the gap in the bobbin retainer is for. Other machines have it this way or very similar too

I have not worked on machines with this type of hook for a loooong time. I guess its a thread take up lever or hook timing issue (or both).

I may have complete tension unit.... will check this weekend. But I´m in Germany.

Don´t know what N66 is but reg. needles - 135x17 and 135x16 have the same dimensions. 135x16 is a needle with a cutting tip for leather whereas 135x17 is for fabric but you can sew leather with it as well. The cutting tip depends on what stitch appearance you want to achieve. This brochure (direct download link) may give you more information reg. needle tips: https://www.groz-beckert.com/mm/media/en/web/pdf/Sewing_machine_needles_for_leather_and_technical_textiles.pdf

when I make turns my needle tip is still in the material the way that I see needle scarf - maybe worth giving it a try. BTW - have you opened your slide plate / hook cover and watched the thread when it slides around the hook? Maybe it keeps hanging somewhere maybe on the bobbin case opener or the hook needs some adjustment - just a guess.

Depends on how heavy you want to sew. Maybe the 45K1 can replace the Singer 7-10 beast and the 78-1 I guess is a good replacement of the Tiny 15K. Thats at least what I would choose.

No you cant but you can move the needle holder a bit sideways. Loosen the screw above the needle clamping screw and try to move the needle holder. It may be stuck if so try to remove it and clean it from oil, gunk and dirt and try again. Whe moving the needle holder make sure the tip of the shuttle hook does not touch the needle.

It was designed as garment / fabric sewing machine but if for sure can handle some light garment leather. But since the seller is your neighbor why don´t you go and test it with the materials you want to sew. Buy some leather needles if he has none and see what it does. Maybe you have to swap out the motor and buy a new servo motor this swill give you a better speed control.

I do not know the machine in particular but to me t looks like a drop feed + needle feed machine with roller foot. I´m not sure but it seems to be a short stitch machine (like 2-3mm or so) cause the slot in the needle plate is quite short. I think it is designed to sew shoe uppers and so forth. Not sure if it suits you needs but I would not pay 1100 for it.

Singer 29K1 or 29K4 manuals will work for the 29K3 as well. There is not a major difference. Maybe a side wheel or a wax pot but nothing really important when is comes to threading or sewing.

Please post pictures of your machine from the underside. I have a Singer 132K6 which is the predecessor of the SK-6. On my 132K6 there is a bushing for the hook drive shaft that is held in place by a set screw. I think when you loosen the set screw you can try to move (hammer) the bushing carefully to the right a little bit so you can move the hook a bit to the right as well. The set screw is probably covered by the bobbin case retainer assembly so you have to remove this first. If there is an adjustment ring on the right side of the bushing loosen its set screw first. I don´t know your machine but that's what I would try.

Its down for quite a while. I have no contact data, sorry. I guess he is out of bushiness or maybe even passed away - I don´t know.

I seriously doubt that there is a major difference between any of the Juki 341 clones. They are all made in China and I doubt there are as many factories that makes them as there are "brand names" that sells them. From what I read Atlas Sewing Machine Co. has a very good reputation. IMO it all depends on how well the machines are set up and how well they are supported by the brand name owner / dealer. I doubt that any of the 341 clones will wear out sooner or last longer than others. If you are new to sewing machines I would buy from a dealer with a good reputation and that is close to you just in case you have troubles that you cannot solve by your self. Sending sewing machines back for service is always a risk so you either service them by your self or you better take it to the dealer by your self. Packing up sewing machines properly is quite a task. Do not expect they will be handled carefully so packaging is the key and shipping is expensive! Since you are in Denver why don´t you check with Ralph´s Power Sewing, they are in Denver! https://powersew.com/ I´m sure they have 341´s too with just a different mane on it. Maybe even used original Juki 341´s.

I once owned a 7-10 IIRC I have used 794 needles. However - have you tried them? Even if it is not set up for 794 needles you can adjust the needle bar height to make them work. thats a tiny domestic machine I´m sure nothing from it will work on your 7-10 beast

I´ll respond to your PM later - anyway the website for the Adler Parts is down for quite a while already. This is the dead link: http://altenaehmaschine.de/ I deleted it from my bookmarks a few month ago.

Glenn, I actually still have it but want to sell it

BTW your bobbin winder looks as if it is incomplete and from a different machine. Maybe worth checking the 45K bobbin winders too https://www.ebay.de/itm/156265077932?

The tension unit remained the same so it is the same on all 29 / 29K machines at least on the most common ones that I have seen. More pictures you´ll find in the thread I have linked in the 3rd post above. I no longer have this 29K1.

I´m not 100% sure but could be that Singer 45K bobbins fit - I´d compare the measures. https://www.ebay.de/itm/143603147753

well, the tension unit looks odd too.... I cannot tell what the silver parts are but they do not belong there.

a few things I noticed... The thumbscrew + lock nut for the foot pressure leaf spring are missing. You have a plain screw instead which for sure is too short. So you cannot adjust the foot pressure. I think (!) you have a wrong foot lift lever on your machine. I think (!) your machine should have the "push down lever" - not sure if you know what I mean but some of the early 29K had a different lever for lifting the foot that you have to push down instead of lifting to lift the presser foot Some one cut a slit in the slider or modified the slider somehow. There should be just 1 slit for the leaf spring and that the is the lower one. The slider also looks modified. the lower end should be squared and not rounded. Usually here should be a spring that hold the "push down lever" in place IMO I think some one tried to fix the machine and made is worse. Please post pictures of the front side. Not sure if you can get it to work with the wrong & modified parts but 1st thing I would try is to place the leaf spring the in lower slit of the slider. BUT I think then the leaf spring will not hold in place because you do not have the correct thumbscrew + lock nut installed. So wrong / missing and modified parts are the main reason why the machine is not properly working. Long time ago I restored a 29K1. You find some pictures that show how the correct parts are positioned in this thread: Hope this helps

Please post pictures of your machine then we know if it the 1st or 2nd type 51w

looks like a clone of the Singer 45K21, drop feed with roller foot.

I´d choose the BROTHER - clone of a Singer 153w (but with reverse) or the later Seiko CW-8 and / or Consew 227R. Its a Singer based machine and parts will be available probably for ever and the accessories like presser feet sets are cheap.