Wizcrafts

I used to own a Singer 15-91 and can tell you what amount of leather it can and can't sew. Technically, anything that can go under the presser foot can be "sewn." But, in my experience, this machine is limited by two un-changeable items: 1: the semi-gutless motor; 2: the bottom feed only with fine teeth. I found that I was able to sew into about 6-7 ounces of bridle leather, with #69 bonded thread, using a #18 leather point needle. This required the foot pressure screw to be screwed quite far down. Sewing the same amount of veg-tan belting required a little more foot pressure. Moving up to an 8-19 ounce piece of the above leathers required the presser foot screw to be screwed all the way down. The drag on top fought against the feed dogs and shortened the stitch length. My attempts to sew 10-12 ounces of leather failed. The pressure spring couldn't hold the leather down and it skipped stitches and hardly moved along. I did try changing to a Teflon foot. This let the leather slide through with less drag. All it accomplished was the maintaining of the stitch length. I even bought a so-called walking foot attachment and installed it. This foot reduced the clearance under the feet and did very little to improve the feeding. The thicker or tougher the leather, the harder it was to penetrate and move it along. The motor would groan and eventually began smoking. I had to rebuild the motor to sell off the machine.

I don't know if you are going to find such thick leather, unless you fold, glue, or sew two suitable pieces together. You might want to look into making a round leather strap using a special technique known in the trade as round reins (horse tack) or round straps (purse straps, dog leashes, whips). There is an excellent tutorial on making round leather reins here. You can try to purchase the needed tools from Weaver Leather, which is one of our supporters with ad banners on top of the pages. They may or may not export directly to China. Good luck with your project!

By the way, the thickest leather I have seen available for sale in the US and Canada is about 1/4 inch, which is about 6mm. I imagine some tannery has thicker sides, but don't know where. When I need to make items that thick I glue and sew two or more pieces together. My Cowboy CB4500 stitcher can sew over 3/4 inch, or 20+mm

I don't have the information you need, unless one of our manufacturers can export leather to you. Hopefully, another member may reply with better info.

It will be helpful if you list your location in your profile. Most members here are in the US, Canada, United Kingdom and Australia, plus Europe. You asked for leather in a metric measurement, so I think you are not in the USA.

Industrial sewing machines usually require a type 3L, or M style v-belt. The width across the outside is 3/8 inch, or 10mm. The inside tapers down to fit inside the tapered groove in the flywheel pulley and belt pulley.

Some servo motors with speed reducers have an advantage over clutch motors in that some of them can be set to spin faster than the clutch motors can. This recovers some of the lost speed that happens with a speed reducer.

WOW!

Call Bob Kovar at Toledo Industrial Sewing Machines. The number is 866-362-7397. He probably has a set of those Singer screws.

I resembles a couple of Singer domestics I have worked on. They thread from front to back, with the scarf of the needle facing to the back. Try that, using a system HAx1 standard domestic sewing needle.

Our member dealers, who have the ad banners in rotation on top of our pages, are the life blood of this forum. Please do contact them about your goals.

You are probably unaware of the OP's location, because he has not listed it in his profile. The machine prices you posted are in US dollars, but our new member lives in the Philippines. Our money and prices don't apply there.

It has to also have an oil pump to be totally self oiling. The pump would be on the bottom and would sit inside a gasket-sealed oil pan. Unless there is a pump somewhere and an oil pickup and filter on the bottom, it is manually oiled. The wicks would distribute oil you squirt into certain holes and reservoirs.

Since servo motors can and do fail, it is important to buy them from a dealer who will send a replacement out if a failure occurs within the warranty period. Some dealers may wait until they receive your motor (and confirm the defect to get their credit) before agreeing to ship a replacement to you. This leads to down time on your part. So, choose to buy from a supplier who will use phone or video confirmation and ship you a replacement with a return label in the box. If you are close to the dealer, picking up and dropping off motors is much simpler and a no-brainer. Price doesn't enter into it once you get a year or two of real use on a good motor. Go for quality and replacement policy.

Your needle and thread combination is perfect for thicknesses between 7 - 10 ounces. I sew suede lined rifle slings and guitar straps that are within those thicknesses with the same needle and thread combo, using a CB4500 or Cobra Class 4. You can tighten the knots by using a #22 needle. For anything between 5 and 7 ounces I would use #92 thread and a #20 needle. It is much easier to bury the knots with #92 (T90) thread. As regards the top tensioners, you should be able to pull the top thread out through the needle and raised feet little to no effort, with the feet lifted all the way up (via the ball handle lifter or foot lifter). If the top disks do not separate with the lifter engaged, the crank with the slot along the bottom may have come out of the little round peg that causes the crank to push up between the disks.

Toledo Industrial Sewing Machines sells bobbins, needles, thread and all manner of accessories for all types of industrial sewing equipment. I even buy my sewing machine Lily oil there.

From your recent photos, your machine is manually oiled. All of the holes with red dye need oil, as well as some that have lost the red dye. Oil after each use and place a cheap rag under the feet to absorb dripping oil. Put a rag on top of the foot pedal until your oil pan is constructed. Use white Lily oil sold by industrial sewing machine dealers (in quarts and refillable 4oz bottles). In an emergency you can buy 4 oz bottles of sewing machine oil at Joann's, Hobby Lobby, or Wally World.

I currently only have 6 fully operating industrial sewing machines in my shop. Additionally, there is a Singer 111w103 head being rebuilt a little at a time (it will share the table with the 31-15). I also have a blind stitcher and a serger, as I do garment repairs and hemming. I rebuild and sell old domestic Singer sewing machines and occasionally pull one off the rack to sew linings, or demo the machine. I still need more machines! I could really use a post machine and curse time and space every time a job comes in that could use one.

When I acquired a 31-15 and table that lacked an oil drip pan, I made one out of Naugahyde and stapled it to the edges of the cutout in the table. I cut a hole for the knee lever lifter. The material side faces up and absorbs oil.

Oops. I was thinking about a National 280 that was in the shop I used to work in. It had dual feed and tore up veg-tan leather.

Be like me and buy more machines as the need arises. Toledo Industrial loves me. My shop is polluted with industrial sewing machines, sewing everything from the lightest cloth up to 7/8 inch thick holsters. Each machine is threaded with different sizes of thread.

There are some gigantic differences. One difference is that the CB105 machine you asked about is single feed, via aggressive feed dogs. You will have to rub out the tooth marks after sewing. It has a static presser foot to hold down the material as the needle does it work. Second, there is no Cowboy CB105 in the US market. Third, if you buy that machine, you'll have to pay for shipping from Australia. Fourth, the machine in the ad is a Keestar, not a Cowboy. Cowboy USA does offer a similar machine, branded the CB2500, which is imported, setup, adjusted, sold and serviced by Toledo Industrial Sewing Machines. It has bottom feed only, but does offer a roller foot instead of the flat presser foot. The range of thread is from #138 through #346. It uses an odd needle system, Type 328, which is longer than a walking foot but shorter than the 441 clones.

Bob sells all manner of walking foot machines. But, most of them are designed to sew upholstery leather with thread sizes not exceeding #138 (T135). Furthermore, they don't usually sew over 3/8" (24 oz) and some max out at 5/16" (20 oz). Right now your package seems to be at 18 ounces, plus or minus and few ounces. This thickness deserves to be sewn with at least #207 bonded thread, or even 277 on top, for a bold appearance. The CB3200 can do that. A standard walking foot machine can't. As a reference, it looks like you are hand sewing with thread that is over a half millimeter in diameter. That is about the diameter of #277 bonded thread. You would use a #25 needle to sew with #277 on top and in the bobbin. That is where the 3200 comes into its own. And the smooth feed dog won't leave tooth marks on the bottom layer.

That roller foot machine will be useful if you make decorative stitched boots, or leather vests, or chaps. It can also edge stitch medium temper belts, using #69 bonded nylon thread (possibly up to #92, depending on the nature of the shuttle mechanism). However, it may not be as useful for sewing cloth as a model that has a standard foot and multi-row feed dog.

M size pre-wound bobbins are sold in a wide range of colors and thread types for modern long arm quilting machines. But, I would still wind my own for bonded nylon thread in sizes 69, 92 and 138.