Singer

[papaw]

I am looking at a singer model15-91 ser. # AJ055039 Built in 1949. It is rebuilt by singer tech Total new power coat. Question is how is the mach. for leather right now I am working with 2-5OZ. What size needle and thread. The singer book doesn't say anything about leather but have read it will sew leather fine. And would this be ok for some heaver leather like belts. To old and don't want to tie up money in something I don't know if I am going to like. I now do all hand stitching and mostly saddle stitch, but hands are starting to cause issues doing it all by hand.

Thanks for any feedback

[Constabulary]

This is a quite small domestic sewing machine. You may be able sew some garment leather on it but it has it´s limits. I´m not sure what needle size it can handle but I think the limit will be a size 19 and #92 thread. The machine is not made for sewing heavier leather, it originally was made for sewing garment fabrics.

[Wizcrafts]

I own a Singer 15-91, which I have been trying to sell for over a year. It can only sew about 3/16" to 1/4" of anything, depending on how thick the presser foot is. Mine maxes out with a #18 needle and #69 bonded nylon thread. They do not feed leather properly with the standard foot, as they are only bottom driven by fine density feed dogs. Switching to a Teflon foot improves the feed slightly. A so-called "even-feed" attachment also helps feed leather, but at the expense of 1/16" lost clearance.

The motor is built into the 15-91 and lacks enough starting torque needed to penetrate 8 oz. belt leather from a cold start. You'd be hand wheeling it to get it in motion, before the foot control could take over. The top pressure spring is barely strong enough to hold down 8 ounces of belt leather, so it will need to be cranked almost all the way down. This adds more drag on the top layer, making it harder to get any appreciable stitch length. Loosening the pressure spring results in skipped stitches when the leather lifts with the needle.

My advice to anybody who is just getting into machine sewing of leather goods is buy a real triple (compound) feed walking foot machine, on an industrial table, with a servo motor, with a 2" pulley. These are great starter machines. They are also the best chap and vest sewing machines in the business. A standard industrial 20" x 48" table will typically have 2 feet from the needle to the left edge of the table. add another 10"+ inside the body and you can sew large flat items with easy.

If you progress further in the leather trade, a cylinder arm machine will be a necessity for jobs that a flat bed machine cannot handle well. Some folks start with a cylinder arm machine that has a flat table attachment, getting the best you can get of two systems in one machine. The work space on the table attachment is nowhere near the space on a real table, but it is better than nothing. Cylinder arm machines are available in compound feed walking foot systems, in light, medium and very heavy duty builds. Most crafters and pros here buy the heaviest duty "441" clone machines, which can sew over 3/4 inches of the strongest leather, with very heavy thread, up to #415 bonded nylon (requiring a #27 needle). There is no domestic machine in this universe than can come anywhere near those specs!.

[papaw]

Thanks for the heads up I'll have to take a look.

[Wizcrafts]

FYI: The difference in strength between #69 (T70) and #415 bonded threads is #69 has a breaking strength of just 11 pounds, whereas #415 breaks at 72 pounds. Most of us use #277 bonded thread on holsters and double leather straps and belts. #277 has a breaking strength of 45 pounds. I routinely sew the edges of single leather belts with #207 thread, which has 32 pounds strength per stitch. These heavy threads reinforce belts and straps and prevent holsters and sheathes from coming apart under stress or duress.

Domestic sewing machines, whether made of iron, aluminum or plastic, are not built with heavy thread and hard leather in mind. Most honest dealers will tell you that their machines on eBay that they call industrial strength are not able to sew with anything much thicker than #69 thread. This is upholstery thread, for light weight seat covers. It is not even strong enough for motorcycle seats unless you go around twice.