kgg

The photo with the nameplate info appears to be for the motor which was made in Croatia. The wording "tvornica elektricnih strojeva subotica" converts to say "Electrical Machine Factory, Subotica". I would send your photo's to USM ( https://usm-americas.com ) and see if they could match up something. kgg

I would like to see the path of the top thread starting from the spool of thread on the thread stand following it as it passes through each thread guide or tensioner to the eye of the needle particularly the tensioner assembly. kgg

Could you post a few photo's of your top thread from the spool to the eye of the needle. I think this is a fairly easy problem to solve. kgg

You probably get better help if you listed the manufacturer of the machine. kgg

I should have used sticking rather then binding. (knee lift shaft is sticking.) Glad the machine works good with the knee lift. kgg

The case you have shown is very similar or the same as the ones made by Libertaz Leathers ( libertazleathers.com ) and here is a video of how they are made. kgg

Yes and No. My two cents: i) Looks like the cooling fan is incorporated in the motor pulley. So getting a smaller motor pulley with the cooling fans maybe limited. ii) Appears to be a 550 watt 6 coil brushless servo motor which would probably work. A 12 coil 550 watt would be better but would cost more (2X). iii) The start up speed could be as high as 500rpm which will give you startup jerk. A speed reducer would help eliminate that or go with a brushed servo motor rather then the brushless servo motor. iv) Make sure the operating manual comes with the setup. v) Like @AlZilla has mentioned the control box is going to be in a awful location under the table so you are going to be down on your hands and knees to change the settings. kgg

I really admire those that hand sew and tool leather but for me I don't have the temperament or the artistic ability. So for me it is all mechanically aided, sewing machines, presses, skiver, embosser, 3D printer, etc. kgg

I do agree with @Dwight but the grit of the sand paper selected has a lot to do with the speed of the machine. Too course a grit say 60 at slow speeds will tear chunks out while too fine a grid at high speed will burn. I use 120 grit on my machine which is a modified variable speed bench mounted buffer with a 4 3/4" long X 3"diameter sanding disk at 3400 rpm. kgg

I took another approach to punching oblong holes in leather belts. I 3D printed two simple jigs, one for the belt buckle holes and one for the other end. kgg

Here is a good threading video for the CB341 starting at about the 8:11 mark for the tension disc. You should really view it from the beginning just to cover off any other potential problems. kgg

Your threading of the top thread around the tension discs is incorrect, refer to your manual for the correct threading. kgg

I use an office chair with caster on all my machine without any difficulty. I have seen the foot lift to be more difficult then the using the rear presser foot lift lever for two reasons. 1) a missing washer on the pivot point of the the foot lift lever at the rear of machine and 2) the point of contact of the foot lift lever at the head needed to be adjusted / oiled where it made contact to lift the presser foot. You should check and see if the knee lift shaft is binding which maybe contributing to the hard lift when using the pedal to lift the pressure foot. Also: 1) The location of the cable to the foot pedal should be mounted to a bracket that is mounted to those two rear holes in the pedal. The closer you move that cable to the pivot point of the pedal the more difficult it is to operate. 2) Since you like using using a knee lift there should have been one come with the machine and it bolts to the shaft extending out of the base of the machine. 3) You should check and see if the knee lift shaft is binding which maybe contributing to the hard lift when using the pedal to lift the pressure foot. kgg

As a suggestion try doing a test piece and compare the result with your present method. Test piece i) Oil the top side of the leather by airbrushing (above 34 psi) first and then lightly oil the backside after letting the topside sit for a few minutes. Let the leather sit for 24 hours to soften and let the oil spread the leather fibres. ii) Then airbrush the top side of leather with the dye (50/50 mix at an air pressure of above 34 psi). Then lightly airbrush the dye to the backside. Let sit for 24 hours or longer then to allow the dye to spread and darker slightly. Then a final light coat of oil. Compare the result with your present method. kgg

I am assuming you are trying for something like the following photo where you have pouch attached to a shealth: You seem to be trying and fold under the bottom of the pouch during your wet molding. I would approach it using a form where the wet leather is placed over the shape form that has the side edges extending about twice the height of the form, place the wet leather over the form and clamp one side down, form the leather over that side and then move to one of the other sides and clamp. I would probably use a 2 inch "O" ring to shape the leather. Let dry for about 24 hours and then damp wet areas that need to be reshaped. This topic shows the shaping tool I would us. kgg