The Type Of Sewing Machine You Need To Sew Leather

[blueflyer]

Great information and vids. Thanks for taking the effort!

Question: Is that "swing arm edge guide" something that comes standard with sewing machines like this or is that something you rigged-up yourself? I am researching a machine to sew leather upper material to foamy/cushiony material. I'm making beach style flip-flops.

Thanks again.

[Wizcrafts]

Great information and vids. Thanks for taking the effort!

Question: Is that "swing arm edge guide" something that comes standard with sewing machines like this or is that something you rigged-up yourself? I am researching a machine to sew leather upper material to foamy/cushiony material. I'm making beach style flip-flops.

Thanks again.

The swing away guide was added on. They don't come with any machine as standard equipment. Bob Kovar, of Toledo Industrial Sewing Machines, sells the swing-away edge guides, along with bobbins, needles, thread, and parts for most industrial sewing machines. Call him at 866-362-7397 to get the current price for the guide.

Edited January 22, 2011 by Wizcrafts

[blueflyer]

Thanks a bunch for the great info Wiz! Looks I will be making a phone call to Bob K. soon.

[ramrod]

this is really a great read, wiz. very well done.

i have questions about the machine i acquired. it's a singer 211g155. it was given to me this past week and i haven't set it up yet. it was apparently used in an awning shop. i'm wondering what the maximum thickness of leather can be sewn on it? and how about the needle and thread size recommendations for leather? is this a compound feed that was mentioned earlier? is it generally a good machine?

i also have a singer 591 that was used in a local clothing factory. it seems to be a real beast and seems to punch through anything, but i've never gotten it to run perfectly.....skipped stitches and all. can you tell me anything about this one?

[Wizcrafts]

this is really a great read, wiz. very well done.

i have questions about the machine i acquired. it's a singer 211g155. it was given to me this past week and i haven't set it up yet. it was apparently used in an awning shop. i'm wondering what the maximum thickness of leather can be sewn on it? and how about the needle and thread size recommendations for leather? is this a compound feed that was mentioned earlier? is it generally a good machine?

i also have a singer 591 that was used in a local clothing factory. it seems to be a real beast and seems to punch through anything, but i've never gotten it to run perfectly.....skipped stitches and all. can you tell me anything about this one?

This is something that should go into its own new topic. Post it anew and I will answer your questions.

[ramrod]

DOH! you're right. i'll get it posted elsewhere.

[neelsaddlery]

[Does anyone know what brands/make of sewing machines Toledo Industrial Sewing Machines Sells?

ferg

Toledo sells a lot of the Cowboy brand sewing machines, as well as a large selection of used machinery and they are also dealers for most of the major brands such as Adler and Consew and many others. They are one of our biggest dealers for Cowboy Sewing Machines.

Edited February 14, 2011 by neelsaddlery

[Ankermann]

This would be a good time to compare home vs industrial motors and needles. You depend on the turning power of the motor to get the first stitch into your material, and the horsepower determines how easy or hard that will be. Once it gets the machine sewing, almost any home style sewing motor will run a sewing machine at a decent rate of stitches per minute, up to its gearing limit. But, that speed is usually only attainable if you remain within the practical limits of material density, needle and thread size. The bigger the motor, and higher its horsepower rating, the more dense the material it can try to penetrate. Most industrial sewing machines come with either a clutch or servo motor, which is mounted under the work table, which the machine rests on top of. A v-belt connects the pulley on the motor to the pulley cast into the flywheel (handwheel) on the back of the machine.

Industrial sewing machines are usually fitted with a motor pulley that best suits the intended work. Upholsters and garment makers want high speed, so they order a large motor pulley, somewhere in the vicinity of 3 to 4 inches diameter, inside the groove. The pulley on the flywheel of garment machines is typically around 4 inches diameter, so these machines are often running at close to 1:1. Industrial clutch motors run at 1725 rpm, at 120 volts, or 3450 rpm at 220 volts (3-phase), so a machine running a 1:1 ration to the motor will sew at that speed. If you were to purchase a used garment sewing machine, even with a 120 volt motor, a 1:1 pulley ration may be uncontrollable for the untrained sewer. A smaller motor pulley is the answer to that problem.

Most leather sewing machines are equipped with a 2 inch motor pulley. This not only slows the machine down to a more controllable speed, but doubles the torque. This comes in as very important when you try to sew thick or dense leather, or bio-plastic projects, or plywood covered cases. Furthermore, if you sew anything other than garment/chap leather at the high speeds used in garment machines, the friction will heat the needle to almost red hot, melting the thread, scoring the leather and usually, causing the needle to grab inside the leather, on its way back up. This causes the leather to lift with the needle. When that happens at the moment the bobbin shuttle's pickup point is passing by the eye of the needle, you will get skipped stitches.

The bigger the machine, the thicker the intended payload, the larger the needle and thread it uses, the slower it must turn. Therefore, distributors of harness stitching machines often include a speed reducer between the motor and the machine. This reduction is at least 3:1, or more. I have an Adler flatbed harness stitcher that was so geared down and its maximum speed was about 3 stitches per second, or 180 per minute. It sure could punch through 3/4" of belt leather at that speed and gear ratio!

Now, on to the pictures. The first photo shows a home sewing machine motor next to a clutch motor. The home motor is rated at 75 watts and has a 1/2" pulley. The industrial motor is a 1/3 hp 300 watt motor, with a 2.25" pulley. The home motor is suitable for driving a home machine through cloth and denim. The industrial clutch motor can sew 3/8" of leather easily with that size pulley. A 2" pulley would give it even more torque.

Clutch motors always run at full speed, but they develop their maximum torque when you engage the motor to the machine. You control them by means of a floor pedal, about a foot square, with a rod connecting it to a movable arm protruding down from the bottom of the motor. When you move your toe downwards on the pedal, the clutch begins to engage, turning the machine. Skilled sewers learn to control the motor from barely turning the machine, to full speed. This takes a bit of practice and the amount of toe required to feather the clutch often depends on the density of the material, and inertial resistance of the machine's mechanism. Also, since a clutch motor always runs at full speed, it always consumes electricity. When it runs under load, sewing, it consumes its rated power draw. Most industrial sewing motors come in these ratings, with the smallest meant for garment machines only:

1. 1/4 hp
2. 1/3 hp
3. 1/2 hp
4. 3/4hp

These motors have a 3/4" shaft and take pulleys made for them and the narrower, 7/16" v-belts they use.

In order to make sewing on industrial machines more controllable, and to reduce the cost of operating the machines on 110 volt circuits, servo control motors were developed. The early generation were prone to premature failure and made a lot of noise as they started up. This has been improved and in some cases, totally overcome, by new controller technologies. Industrial sewing servo motors are available in a range of power capacities from about 1/2, up to 3/4 horsepower. Their wattage ratings vary, from about 300, up to 600 w. The nice thing about all servo motors is that until you press down on the floor pedal, they do not draw more than 1 watt. You can leave a servo motor turned on all the time and not notice it in your electric bill, unless you are actively sewing a lot.

One of the shortcomings of many servo motors is a lack of startup torque. While they do produce their rated drive power at full speed, the opposite is true at slow speeds. That is another reason why many leather stitchers ship with a speed reducer pulley under the table. It doubles or triples the slow speed torque, while also reducing the maximum speed to one that won't burn up you leather and thread.

There is a new type of servo motor that has been produced, to overcome the problem of low slow speed torque. It is a gear reduction motor, currently marketed under the brand name "SewPro." I have their model 500GR. It features a 2" pulley and a speed limiter knob on the back. It runs at a maximum speed of 1500 rpm. This machine only consumes 300 watts flat out, but has a 3:1 reduction system, giving it the same power as most 3/4 hp servo motors. I have one and love it. I can sew from under 1 stitch per second, to about 10 to 12 stitches per second (depends on the diameter of the flywheel pulley). It is a bit low for upholstery, but not unacceptable. It is perfect for leather, which is what I mostly sew these days. It sews marine vinyl like it is butter.

Here is a picture of my SewPro 500GR servo motor, mounted under the table of my 75 pound National 300N walking foot machine:

Next, let's compare a couple of needles. The one on the left is a #12 home sewing machine needle, used to sew thin cotton thread into shirts and pants. The needle on the right is a number 25 needle (series 135x16), used to sew up to #277 nylon thread into leather holsters and straps. Home style sewing needles are not usually available in sizes bigger than #18, although I found some #20 on eBay. Series 135x16 (leather point) and 135x17 (ball point) are available in sizes up to #25. As a reference, #69 nylon thread, commonly used in upholstery and marine vinyl sewing, uses a #18 to 20 needle. Stronger results are achieved with #135/138 nylon or polyester thread, which requires a #21 or #22 needle. This leaves out all home machines, including the ones sold on eBay as "industrial strength."

Here then, are the home and industrial needles, side by each:

Now that you have seen comparisons of the motors and needles used by home and industrial sewing machines, you'll have a better understanding of what is required to sew leather.

[Ankermann]

This is one of the best descriptions I have seen. I am going to mention this in my add for

Ebay when I sell my machines. These people on ebay trying to stuff 1/4" or more leather

in those machines are crazy. Those machines were not made for that type of sewing.

This was very helpful to me. I collect and sell machines and I just learned a whole lot!!!

Thanks very much....

[tackmantoo]

Content to be added and updated on an ongoing basis.

Welcome to the Leatherworker.net Leather Sewing Machines Forum! If you are new to this forum and you are seeking information about the right type of sewing machine you'll need to sew leather, you're in the right place. Everything stated below is either my honest opinion, or the honest opinions of other members of this forum. We all have personal hands-on experience sewing a broad range of leather projects on a broad range of sewing machines. Most of us have worked our way up, trying different machines, fixing up old ones, modifying them, tricking them out, all in usually fruitless efforts to sew something they are simply not capable of sewing. This is especially true when it comes to sewing leather.

Leather varies in texture, weight, stickiness, thickness, density, dryness and chemical composition. No doubt, some of you have seen pictures and videos online, showing this or that machine sewing leather. Those pictures are uploaded by the seller of the machine, to broaden their purchasing audience. What many first time sewers don't realize, is that just because a particular machine is said to be able to "sew leather," that does not mean it will do it well for the types of leather the buyer wants to sew. Leather varies, as stated above. The machines that can sew garment weight leather may not be able to sew chaps, belts, tack, holsters, or saddle bags. Just because a machine is large, or metal bodied, or or even industrial, does not make it a true leather sewing machine!

First, I will address the machines seen on eBay, sold as Industrial Strength sewing machines. Most are all metal and proudly state that fact. The sellers talk about the "powerful" 1.2 or 1.5 amp motors that are attached. Some even have ribbed drive belts and gear reduction, to eliminate slippage when sewing thick material. No doubt these are strong machines. I have a few myself. I have 2 old iron body Singers and a metal body Kenmore, even an ancient White Rotary machine. Will they sew leather? Yes, two layers of 2 to 4 oz garment leather. Will they sew leather with nylon thread? Yes, but no bigger than #69 nylon. Will they smoothly feed garment leather as it is sewn? Yes, as long as it is fairly small in size and weight and not stitcky on the top grain. If the top is sticky, no way, Jose. Sticky vinyl and leather usually gets dragged back by the top pressor foot and the stitches are either too short, or filigree the material, or skip frequently.

Sticky material, like smooth top grain chrome tanned garment leather and Naugahyde (vinyl), does not feed evenly unless the pressure on the "pressor foot" is reduced significantly. All of the feeding is done from the bottom, by the teeth in what are know as "feed dogs." The pressor foot has to apply enough pressure to the top of the material to keep it from moving between stitches and also to prevent it from lifting with the needle, as the needle begins its ascent. This is when the thread in the needle's eye forms a loop for the rotating or oscillating "shuttle" pickup point to grab. The grabbed top thread is then pulled around the bobbin case and bobbin thread, which is pulled up by the lifting take-up lever, to create the lockstitch inside the material. If the top pressure is insufficient for the thickness and density of material being sewn, the material will lift with the ascending needle and top thread. When this happens the loop may not be formed and there will be skipped stitches. Even if the material is held down by the foot to form the stitches, the spring pressure may not be enough to hold down dense veg-tan leather when the take-up lever lifts up. If the leather lifts during the take-up phase the stitch length will vary wildly, the layers may slide out of alignment and the needle may deflect and break. This can also cause skipped stitches.

In an effort to overcome the problem of feeding sticky vinyl and leather, sewing machine companies and aftermarket manufacturers produce add on pressor feet to make it easier to feed these materials. Some dealers sell replacement feet with little rollers inside them (roller feet), or teflon plastic feet that claim to allow sticky material to feed better that steel feet. Others sell actual rolling wheel pressor foot attachments and sets, where the foot, feed dog and throat cover plate are replaced as a group. Finally, you can usually find a replacement foot called an "even feed" foot, or "walking foot" attachment. It contains an inner and outer pressor foot, which alternate up and down as the needle moves up and down. This is done by a lever that is hooked on top of the needle screw on the needle bar. The inner foot presses down and moves as the needle lifts out of the material and the feed dogs pull the material back. When the feed dogs reach the preset stitch length they drop down (drop feed) and the inside foot lifts up with the raised needle bar and snaps forward. The outer foot then drops to hold the material in place until the needle has penetrated the work again and is ready to form the next stitch.

This is not a true walking foot, as is used in true walking foot machines. It is an effort to improve the feeding ability of the wrong machine for the job. An add-on walking foot will not actually help you feed heavy garments or chaps through the machine, but it will allow the leather or vinyl to move and stitch without stitcking to the bottom of the pressor foot, allowing you to increase the pressure to prevent lifting, shortened stitches, or skipped stitches. If the material being sewn is long and wide, or heavy, your machine will have trouble pulling it back to form the stitches, despite having the even feed attachment installed. There are no teeth on the bottom of the pressor feet and the material can slide easily with a little tug, or from the weight of the work folding over the front of the work table.

I have learned that these even feed attachments usually reduce the clearance under the feet. This means you cannot sew as much thickness as with the standard foot. If you raise the pressor foot bar for more clearance, the needle bar, or top thread guide on the bottom of the needle bar will hit the inner pressor foot. They are a compromise feed system.

Even if you are able to feed the material through an industrial strength sewing machine, you are going to be limited in the thickness that it can sew, as well as the size of thread it can handle and the sizes of needle it can use. Number 69 bonded nylon thread is fine for leather vests or small vinyl projects, but is not so good for upholstery or chaps, or anything thicker, like belts and bags. For these projects, you'll want to use at least twice the size of thread: #138. At this point, most home machines drop out of the picture. Even a lot of actual industrial machines will not sew with #138 or larger nylon thread. They might be able to sew soft polyester or cotton thread in larger sizes, often sold a button or topstitch thread.

To properly sew leather you need an actual Walking Foot sewing machine. In my next installment I will define the various types of walking foot machines and what makes a dedicated leather stitcher different from a leather-capable sewing machine. I have to go earn my keep now, but maybe some other members will add to this topic.

Later!

Barra; Joanne; can this become a Sticky topic?