The Type Of Sewing Machine You Need To Sew Leather

[Wizcrafts]

This ditty is about the different types of pressor feet used on home and industrial sewing machines. Using the right foot makes your work feed and stitch better than is otherwise going to be the case. These photos will give you a frame of reference.

First, here is a picture of the standard static (flat) pressor foot used on a Kenmore home, or straight-stitch industrial sewing machine:

This is what you get with most straight stitch garment machines. Most other home machines come with a straight stitch attachment foot. All older machines, up to the late 1950's tended to be straight stitch only and one needed to attach an add-on mechanism to sew a zig-zag or button hole stitch. Now, they are standard on most home machines and you can buy industrial zig-zag machines as well.

Here is a zig-zag pressor foot:

This is a cording or welting foot (straight stitch):

A roller foot makes it easier to feed sticky material, like vinyl and garment leather. Here is one inexpensive type of roller foot:

Here is what eBay sellers tell you is a walking foot, or even feed foot:

(kinda looks like an alien bug invader!)

This IS a walking foot:

[Wizcrafts]

What is the difference between an all metal, "industrial strength" sewing machine and an actual "industrial" machine? The first term is a favorite of eBay sellers to help move out old, refurbished clunkers and antiques. Tell somebody new to sewing that a heavy, all metal machine sews leather, show them a stack of dimes under the presser foot and provide some photos and samples of the leather it can sew, and they will have all the sales they want.

Unfortunately for the buyers, most will not be able to sew the type of leather they bought that machine for. I frequently see newbies asking if the old Singer in this or that eBay ad will sew chaps, belts and holsters. It usually starts out with they only want to sew garment leather, but by the second reply the heavy stuff pops into their description. The thinking is understandable: that machine was advertised as being able to sew real leather. Yes, it can sew leather, but only thin garment or light chap leather and not without problems of dragging the top grain on the presser foot.

I think that a picture is worth a thousand words, so here is one I took of my Industrial Strength Singer 15-91, fully rebuilt and setup to sew to its best capacity, next to my National 300N walking foot machine (equivalent to a Consew 206RB).

Not in its wildest Robot Dreams will that 1953 Singer 15 class machine sew anything much thicker than 1/4", with thread no larger than #69 (maybe #92), without babying the material through the feed mechanism. I know; I tried. I had to install a walking foot attachment to get it to sew marine vinyl, two layers thick, because the material was dragging under the foot. This reduced the maximum clearance to under 1/4." Holding the material tight to keep it aligned caused it to change stitch length or break needles. Sewing leather was not a joy either, just a big hassle and more broken needles. The most aggravating part of sewing with a home machine is the tiny motor that drives the mechanism was bogging down at startup and I had to hand-wheel to help to go. Most so-called "industrial strength" machines have a motor rated at about 1/10th to 1/15th horsepower, 75 to 150 watts.

When I finally got a-hold of the National 300N walking foot machine, it came with a 1/3 hp, 1725 rpm, 300 watt clutch motor. It was set-up for sewing upholstery and had a 3" pulley on the motor. It was difficult to control and I know how to operate clutch motors. A phone call to Toledo Industrial Sewing Machines cured that problem. He sold me a SewPro 500GR servo motor, with 3:1 built-in gear reduction and a 2" pulley; the equivalent of a 900 watt motor. I haven't had any control or penetration problems since. This machine will sew over 3/8" of actual leather belting or harness strapping. It uses needles up to number 25 and thread up to #207. I can control the servo motor at any speed, even less than 1 stitch per second.

Having the actual industrial walking foot machine allows one to hold back the work and it will still feed without changing stitch length, or popping needles from back tension. You can turn on more top pressure to keep thick and dense leather from lifting under the foot, causing skipped stitches. If you intend to sew everything from leather garments to belts, a real walking foot machine is the best way to go. The feed mechanism is too rough to use on light cloth garments, but works great on denim and vinyl. It walks over seams effortlessly.

That's all I have time for now. More to come later on.

[Wizcrafts]

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.

[Wizcrafts]

This article is now being Tweeted on Twitter. Thanks all!

BTW: I am @Wizcrafts on Twitter. My tweets are mostly about computer and website security, malware threats and spam analysis, but I do make the occasional Tweet about my leather and sewing work.

Today is my birthday, so I probably won't be posting anything new today. I'll get back to this article later, or tomorrow. I know I have a contract sewing job to do sometime tomorrow. Maybe I'll shoot a couple of pix of my walking foot machine earning me some money. It may help someone who wants to sew similar leather projects.

I have shot a few movies of my machines, with my digital camera, but haven't figured out how to convert them from Apple .MOV files into WM .AVI files. I may see if YouTube has a converter and upload them there, for the world to see (in Flash format).

[CJ1]

Hallo,

I was just reading you post.very interesting. Maybe you want to take a look at Member CJs Leather Repair(my wife).She got an "old girl" posted you might wanna see.This machine is unbelievable.She goes through leather up to 1"thick and more...

Besides Happy Birthday..

[Wizcrafts]

If you intend to sew leather straps, a walking foot machine makes it so much easier. I have just uploaded a video, to YouTube, of my walking foot machine at work, sewing a rifle sling.

! Read the description for further details about the job being sewn.

The next videos will have better closeup details, but this one will show newbies to sewing leather straps how it is supposed to be done.

[Ferg]

Great information!!

I have been interested in sewing most anything since a very small child with Mom's treadle singer.

Never have convinced my wife that I need an actual leather sewing maching. LOL

ferg

[louisduck]

I love that national 300, I wish I could find it on ebay...What do you think of the sailrite LS, is it comparable?I also found a machine called sew-line around $200. I wonder if I should save some money to buy the right machine (to make leather purses).

Thank you for you very informative posts!!

[Wizcrafts]

I love that national 300, I wish I could find it on ebay...What do you think of the sailrite LS, is it comparable?I also found a machine called sew-line around $200. I wonder if I should save some money to buy the right machine (to make leather purses).

Thank you for you very informative posts!!

My machine is close to a Consew 206RB, with the exception of the top pressure spring being a different type. There are plenty of 206RBs for sale on eBay, and from some of our member dealers.

I have never had or used a portable walking foot machine, so I can't say what I think of any particular brand. On the other hand, I can advise you about what modifications will be needed to use a Sailrite, or equivalent portable machine for sewing leather. According to Bob Kovar, at Toledo Industrial Sewing Machines, it takes the dealer about an hour to un-box and setup a new portable walking foot machine, to get it ready to sell and sew. After that, if you are going to sew any leather that marks easily, the pressor feet need to be replaced with smooth bottom feet. If the buyer intends to sew belt leather, a Monster flywheel is needed, which costs about $130, from Sailrite.

I would not advise you to buy a $200 portable walking foot machine on eBay. You will probably regret it. Plan on spending double that amount for a decent portable walking foot machine, or over triple for a Sailrite. Then add the extra pressor feet and Monster wheel, for another $150, or so.

Some of our members buy these machines and modify them personally. There is at least one old thread here about modifying the pressor feet for more clearance, by grinding off the teeth and repositioning the outside foot by lengthening its mounting hole. After that mod you can sew 3/8", with the Monster wheel addition.

If you want to learn more about what to expect from a portable walking foot machine, contact Bob Kovar, at 866-362-7397. He sets them up and makes sure they are ready to sew, before they go on the truck. His price is reasonable and he takes care of warranty work himself. He also sells pressor feet and accessories for them.

[glennaycock]

Wiz,

Thanks for all the great information! I read your take on "industrial strength" junk on Ebay.

I'm in the market for an entry level (inexpensive) industrial machine for leather upholstery and motorcycle seats.

On Ebay, there is a bewildering variety of new, Chinese-made machines, all apparently produced in the same factory and branded as Juki, Feiyue, Consew, Sailrite, Yamata, Family, Morris, SEWLine -- even Pfaff and Singer. I've got my eye on the 8300/8500/8700-type models and the similar walking-foot models.

I believe companies like Sailrite may import their machines and make improvements and/or at least test them thoroughly, based on their website and videos.

I have read comments like "Juki, Pfaff, and Singer machines aren't what they used to be." Since it's inevitable that most manufacturing is moving to China these days, can I assume that these machines that look identical are identical? The material qualities could differ or the internals might be different.

I'm very confident I could handle most mechanical issues, but I am hesitant to risk a large sum for an imported machine, particularly with high shipping charges, when I am unable to find any/positive reviews.

I see posts for various machines locally on Craigslist, but I am concerned about their age/condition/history for the price. Should I try to find an older Japan-made model or new(er) Chinese model for same money?

Your guidance is greatly appreciated.