Constabulary

maybe safety clutch triggered - if it has one.

DOT, CS Osborne or Stimpson with brass "core" DOT also has a PULL THE DOT line which is much stronger that the plain ring snaps nut not very fashionable so depends on the purpose.

Maybe try a Teflon foot or roller foot (both dirt cheap). You seem to sew the material "unguided" (no hands on the material) have you tried "spreading the light fabric with thumb and fingers a little bit?

But it will not fit your 239! The 239 have lot in common with Singer 111 but NOT the needle plates and feed dogs! If you are able to cancel the purchase better do - it will not fit!

Inline foot set your needle plate cut out is short enough so the outer (now rear) foot can rest on it. I had to order a new needle plate + feed dog for my 111G156. MIne is on the way: https://www.ebay.de/itm/154704899719

or maybe a an "inline foot set" but not sure if that works on your 239. You may need a needle plate with a shorter cut out then cut off toe so the (former) outer foot can step on the needle plate right behind the inner foot. Know what I mean?

Looks like an quite early black machine with paint quite worn off. I´m not sure but maybe at that time there was no H1-H4 rating. Bobbin are usually all the same in the 14x class (approx 22mmx11mm). Needles depend on how the machine is set up you can set it up for different needle system by raising and lowering the needle bar. Not a big deal really. Keep in mind - what you see on the tag is how the machine left the factory decades ago and it is well possible the machine has been altered / set up for different purposes several times (old machine) during its lifespan. Best way to figure its specs is testing it. Old / worn machines are always a gamble.

I do non´t think you will find a 100% matching paint of the shelf. I´d check home depot (or similar) and buy some brown rattle cans. But if this is of major importance for you and you really want it very close I´d check with a paint matching service or your local car painter, they may be able to find the closest shade for you. You may have something like this locally: https://www.myperfectcolor.com/Custom-Color-Matching-Services/33936.htm or try a color detecting App for your phone (the one with out wires ) like Color Grab https://play.google.com/store/apps/details?id=com.loomatix.colorgrab&hl=de&gl=US

roller foot is not possible on tripe feed machines. You need a drop feed or needle feed machine for that.

I don´t know the answer but I can guess. Knowing similar machines have a bobbin case opener on the hook - maybe the 3bl has no bobbin case opener. You will notice when you look on the underside of the machine. This is just a wild guess!!!

That basically it is a Adler Class 4 machine only Dürkopp labeled (Dürkoppp and Adler merged in 1990). Pre 1930 manufactured I think. Needle system is 328.

sorry - I was on the wrong track with my SV machines statement I had the thread with the 133K darning machine in mind Looking forward to what the Singer museum will say...

I only can imagine a "hole puncher" - but don´t ask me for what purpose. I really have no clue. Is there a drive shaft for mounting the hook?

That indeed is interesting.... Well its an SV machine - very little to nothing is known about certain SV models, some are predecessors of later standard machines and some are kinda prototype or made for a special customer application.... no one really knows em all. Maybe yours had tension units positioned somewhere else. Right - no slot for the take up lever - very odd. Can you post a picture of what is behind the face plate please. EDIT: Just a guess - no hook, no tension units, no take up lever - was this machine for what ever reason meant for just punching holes into... what ever????

That can be fat / oil too. Experts call it spew afaik. When leather is a bit over treated and is exposed to different temperatures the "white stuff" appears and sometimes even disappears when it gets warmer. Try a hair dryer and see if it disappears. I had that on 2 old M-1916 holsters from WWII. First I expected mold but the holsters next to them had nothing. Did some research and figured temperature differences can cause that the "white stuff" appears... It´s a guess cause situations can be different. EDIT: https://www.lttleathercare.com/spew-on-leather-not-what-you-think/

#18 and #22 are both 135x17, right? So a different needle size usually does not require retiming. Needle hole in the feed dog have to be large enough for the #22 needle and make sure the hook tip is not touching the needle if it does well then the needle is too big for the machine cause you cannot move the hook further to the right AFAIK. EDIT: just realized its a double needle machine - not sure if you can move the posts sideways a little bit when the hook is touching the needle. EDIT II: you can - I just checked the manual : https://www.manualslib.com/manual/364365/Singer-138w102.html?page=11#manual

Don´t know where you come from but beside College Sewing Trojan Sewing UK has parts too: https://www.trojansewing.co.uk/product-category/industrial-sewing-machine-spare-parts/singer-industrial-sewing-machine-parts/singer-132-k-industrial-sewing-machie-parts/ You need the top and main tension units some thread guides too and a bobbin winder. Just what I notice from the picture. BTW - the Seiko SK-8 and Mitsubushi DY-253 share a lot of parts with the Singer 132K / 133K machines - just as a hint when looking for parts. Once you have completed it you may need timing values for the needle-hook timing - you find a good manual for the 132K / Seiko SK-8 here in the 1st post (values are the same as for the 133K´s)

I once restored the short arm version of your machine (kind of) - a 133K3. Not exactly the same in short but very close as it seems. Pictures here may give you and idea what parts are missing on your machine: Oh - BTW - just yesterday some one else posted his 133K darning machine - he probably would sell you some parts (guessing) - check this: Furthermore College Sewing in the UK has a good range of parts for the 133K / 132K but seems they have a website problem.

To be honest I would give this to someone professional cause matching the color and airbrushing the spot or so will not be an easy task and the pros may have different products for different type of leather plus they (hopefully) have experience with this. If it was a dime size spot I would probably try DIY but this is a huge and dominant spot and I don´t think you can match this up without experience and knowing the right products and techniques. My 2 cents cheap way - throw a blanket over it **kidding** EDIT: not your language I guess but maybe a website translations gives you an idea https://www.lederzentrum.de/tip/moebel/glattleder.html#videoanleitung

Regarding binders - maybe College sewing in the UK has what you need. https://www.google.com/search?q=college+sewing+Binder+50mm Not sure what source you have in France but maybe you can check with Zieger in Germany for custom made binders https://www.np-z.com/sonderbau

as sad as it is but you may get more for this machine in parts and for the nice stand, large thread stand, bobbin winder, hand wheel.... than for the whole machine sold as daring machine. A lot of parts are compatible with other 133K / 132K models not all but for sure many. My 2 cents BTW - this is a manual (download link) for the 133K6 but it´s not for the darning type but you may notice the differences: https://leatherworker.net/forum/applications/core/interface/file/attachment.php?id=145755

No, I´m sorry. Question is how much demand is there nowadays for a machine like this.

Basically you cannot sew knife sheaths with it. And for sure no one ever has sew boot soles on it. The guy who told you this did not know what he was talking about - I´m sorrry! Darning machines are for darning sacks or closing sacks.

Thats what I almost expected - it unfortunately is a darning machine not a sewing machine. It has a typical darning foot and no stitch length adjuster and no feed dog for feeding the material.

Can you post some pictures of your machine please? Some 133K´s were darning machines. I don´t know the 133KSV1 so would be good to see some pictures. I once owned a 133K3 which was a quite nice drop feed machine.