Are you using a button die and press? If so you just load the button parts and the circle of upholstery. In the die and then press it all together.

You can buy binders of ebay that are reasonably priced, but you need to understand how many folds you want meaning raw edge or finish edge and the width of material that you need to feed it.

You will probably be better off looking at John Deer’s sight (NOT the tractor). It has a lot of good info for all of the different aspects of embroidery. The brothers are good for learning and to figure out if you really want to do this before you sink a lot of money into it. You will quickly outgro...

Do you have picture of the bottom of the back, as well as 3 sides of the seam along the edge.

Trying to understand if this is a false back, or if the back was attached and then the upholstery finished.

Reassembled:

Plastic stud weld I was referring to:


After unwelding:


Next step would be to pull the edges of the studs up so they do not catch when reassembled. Then reassemble and melt the 2 pieces back together.

Is the presser foot clearing the material when it walks?

I run into that issue when I pause my machine mid stitch and then start sewing again.
Usually in my case it seems like the hook catches the thread twice.

When I see old upholstery that has the cloth and wire; the cloth is usually muslin, and the size of the wire seems to vary depending on how long it is and how much load it has to take.

Now a days it is more common the see velcro type assemblies or j clip/rail to replace the cloth and wire.

I use the mercury pen, which is the silver ink that can be removed with a damp cloth. I bought the pen from tandy leather and get the refills on ebay https://i.imgur.com/nSmHi82.jpeg You want to get the refills, the ink is consumed a lot faster than a regular pen. I use it to mark all my upholstery,...

Does this include cutting down the tree to get the wood for the frame?

Here is the current inseparable assembly that I am working on for a dealer. The only inseparable assemble that I have run into that is truly inseparable are on BMWs they take inseparable assemblies serious. https://i.imgur.com/QZS25Rn.jpeg https://i.imgur.com/1F0MHHs.jpeg https://i.imgur.com/cB6hUQc...

I use a torch. I reshape the pins the same way I remove scratches from the front side of the door panel. You affect only the surface of the plastic. If you affect the plastic in depth it will lose structure and you will make a mess. This does not work for thermoset plastic, it only works for thermop...

Do you mean the ones where the door is held together with melted plastic pins?

If so I usually just unmelt the pin and reshape it then separate the pieces. Then afterward put it back together and melt the pins back down.

It looks similar to the Consew model, so maybe the Consew direction will be helpful.

What do you plan to use it for?
While it is an industrial machine, it appears to be light to medium material. Not heavy material such as upholstery materials.

The 18 needle may be too small for 69 thread in the leather you are using. A 20 or 21 may work better to provide clearance in the leather. It is also still possible that the machine is tuned for a 14 needle and the 18 is too far from 14. But if you are happy with the light weight thread that is fine...

I typically make the foam 1/2” larger on each side. So 1” in length and width.
This will put the upholstery in tension, however, the higher the density foam the harder it will be to put the cover on the foam, so if it is a high density foam you may not want so much oversize.

Not saying it is not possible, just that you may not have the right needle, thread, material combination for this specific application. You probably need a bigger needle to make a bigger hole to provide more clearance for the thread in the leather. Not sure what your needle, thread combination was f...

I have broken even larger thread, T270 with a nominal needle, while sewing into leather because I had the tension so high trying to pull the stitch into balance.

Did you change the needle with the smaller thread or are you using the 18 needle with a smaller thread in the leather?