kgg

Keep in mind that NO one machine will do everything that is why some of us have more then one or six machines. You need to figure out: i) your max budget dollars ii) what is the thickest thread you want to sew with, V69 (domestic), V92, V138, V207, V277, V346, V415? iii) what is the thickest you want to sew including the seams? iv) what are the articles you are planning on making the most? v) You need to read this article to help figure what would work for what you want to sew. kgg

With any sort of odd ball machines finding parts can be a chore and then add only one supplier of parts I would personally steer clear of the machine. That said if the price was dirt cheap, not $800, then maybe. kgg

From the Thread Exchange website ( https://www.thethreadexchange.com/miva/merchant.mvc?Screen=CTGY&Category_Code=needle-systems-singer-148-to-231-SV-12#Models_178_to_211-GX ): Singer Model# 196-K 301 uses needle system 287 Equivalent to 287 H, 16X21, 16X269, 376, CANU 11:60 That will bring you to their selection of needles for that machine choose the correct needle size based on the thread size you are using. kgg

Save your money personally I think you will be disappointed with the abilities of the that machine it is not an industrial sewing machine. Those machines and their clones were meant as machines to repair sails when at sea. I have owned a few of the Sailrite machines and their clones. They are really meant for limited use in thin stuff. It will: i) leave marks in leather as the standard presser foot and feed dog are very aggressive. ii) uses a domestic Singer Class 15 small bobbin iii) thread size is limited to V92 thread iv) stitch length will vary as the thickness of the material increases and the list goes on. kgg

Are you using a speed reducer between the servo motor and the needle positioner? I would first replace the belt. kgg

I approached the problem with inline binders by installing 3mm brass inserts for mounting in a 3D printed table top. I think you could do something similar with the table top you have. ( drill / tap or drill and press in a nut) kgg

If I'm not mistaken the Techsew 2600 is a clone of the Juki DSC-246 a manual for the Juki can be downloaded here: https://www.juki.co.jp/industrial_j/download_j/manual_j/dsc240/index.html kgg

Just go to your local hardware store and get a V belt. The link belts don't provide the same amount of belt surface contact area as a V belt. Looking at your photo and the video of the machine on the Jiang Long site this machines appears to be a needle feed machine where the outer presser foot just goes up and down like a ordinary drop feed while the needle and the inner presser foot moves back and forth. What are the model numbers of the comparable machine?? Without knowing more about the spec of your machine or what it is a clone of you maybe be at the machines limit, probably around 8 oz. kgg

Start with basics first. i) Are you using needles that came with the machine. If so throw them in the bucket as they are more then likely to be of poor quality. ii) I am going to assume the machine takes system 135 needles. Are you using a 135 x 16 which is needed for leather? iii) What size of needle are you using? You may have to move up to a #22 needle for V92 in thick / tough leather. Reference chart ( https://www.tolindsewmach.com/thread-chart.html ) iv) have you checked to make sure the feed dog is set correctly. The presser foot tension just needs enough downward pressure to move stuff along. To much doward pressure and it's like creating a jam point. The drive belt needs some slack otherwise it puts to much strain on the bearings in the machine and in the servo motor. I would remove the belt and turn it over by hand and see if can feel anything funny. Is this a needle feed machine? kgg

I would first determine what the running length of the dies you want to use are and from that you can determine the required tonnage that will be needed. kgg

Someone definitely Frankensteined that machine. The machines is a drop feed tailor machine made for fabric. This machine is not meant to sew leather. The .6mm thread that you normally use is equal to approximately V277 which will need a #25 ( 200 ) size needle which this machine will not take if you can find the correct 16x 257 needle system. If you want try and use the 134 or a 135 x 16 needle system the needle bar height will probably have to be adjusted and the needle to hook timing adjusted. You really need to install a new thread tension assembly and the other missing guide to get the thread tension and path correct so the machine to will sew properly. Here is a link to to a good needle size to thread size chart ( https://www.tolindsewmach.com/thread-chart.html ). Here is a copy of the parts manual and a correct tension assembly. kgg Singer 31K15, K17, K20, K22, K32, K45, K48.pdf

The leather and needle are lifting the presser foot like @Northmount has noted but also catching the thread as indicated by the loop being created at the needle. The 135x16 is the correct needle system for leather but what size of needle are you using? Here is a good chart for needle size verses thread size but in thick or tough material you should move up a needle size. If you are using a #20 needle go up to a #22 needle. The machines max needle size is a #22 and the max thread size is V92. I have owned a couple of Sailrite LSZ and clones and real life will show you with tough / dry / dyed leather you are at roughly the max sewing thickness that machine can handle. Also what I did find with those machines: i) is they can be really particular with the needle being installed as in that it almost has to be perfectly installed and any deviation especially in leather you can run into problems. ii) stitch length will vary as the sewing thickness increases. kgg

Thank you. Good price. kgg

Looks good. I would recommend flushing it with a lot oil to get rid debris from manufacturing and to make sure every surface that touches another is thoroughly lubed. What was the approximate cost with shipping / duty. kgg

A wheel foot will not work with a walking foot machine. What machine are you using? kgg