Wizcrafts

It is a high speed garment maker's and tailoring machine. Forget about sewing most leather with this machine.

I often edge stitch bridle leather belts to reduce stretch. This works better on larger sizes that exert more pressure on the belt. I use #207/207 thread into 8-9 ounces, or #277 top/207 bottom on 10-12 ounce belts. Anything thicker, or double leather belts, I use 277 top and bottom.

I have published and others have contributed to a long topic regarding the type of sewing machine you need to sew leather. Newbies to machine sewing of leather will get a lot of fetchin' up reading this before buying an old iron machine on eBay, or your local Craigslist, or Sally Ann store (with some exceptions). The so-called "industrial strength" (often misspelled) machines are domestic machines designed to sew shirts and pants. Every one is a bottom feed, flat foot machine. They do not sew thick leather (anything over 1/4"), with many maxing out at only 3/16 inch. None of them keep multiple layers aligned, because the drive is entirely on the bottom, with the steel foot holding down the top, to keep it from lifting with the needle, which would cause skipped stitches. Most can not tension thread heavier than #69 bonded (T70), or #80 polyester jeans thread. To even sew with these relatively thin threads requires the largest needle commonly available for that class of machine (#18 or a "topstitch needle"). I read a post eralier in this topic where a member asked about a White sewing machine. If it has the same rubber friction wheel drive as the old metal body Kenmore, it barely powers through denim. The slightest resistance from the material causes the motor to slip against the handwheel and rubs a channel into the little rubber wheel on the motor. You'd end up hand-wheeling through leather, as the motor is useless. All domestic sewing machines have teensie weensie motors on the back or inside the body. The ones that shipped with the machines of the early 20th Century were usually rated at no more than a half amp at 110 volts AC. That's about 55 watts of power.This was sufficient to power through cotton shirts. Later around the middle of the Century, motors became available rated at up to 1 amp. Now, one can buy replacement motors rated at up to 1.5 amps, or 150 watts. That is it for the domestic motors on the back of the machine. Machines with built in motors, or pod motors, cannot be upgraded. While the 1 and 1.5 amp motors will power a machine through denim and canvas and leather vests, they bog down when you try to sew belts or pancake holsters. Their torque is somewhere around 1/10th horsepower. In contrast, an industrial walking foot sewing machine, mounted onto a k-legs table and steel frame, is usually powered by a clutch or servo motor rated at about 500 to 600 watts. They often draw 5 amps under load and are rated at about 1/2 to 3/4 horse power. They are 4 to 5 times more powerful than the strongest domestic sewing machine motor. Walking foot machines have triple feed from a coordinated motion of bottom feed dogs-needle and inside foot. An outside presser foot lifts to allow the feed motion, then lowers to hold the material securely between stitches and the needle ascends and the knots are formed. A typical true industrial walking foot machine can sew 3/8 inch of veg-tan, bridle, or latigo leather. They power through chrome tan like butter. These are upholstery class machines. Many have 50% larger M style bobbins. Juki machines are available with even larger, double capacity LU style bobbins. An average upholstery class machine can sew with #138 thread, top and bottom; double what any domestic machine can think of handling. Specially setup machines in this class can handle #207 thread. Then, if one becomes serious about sewing leather, one will learn about the 441 class machines that sew over 3/4 inch, with 44 pound test #277 thread and heavier (346, 415).

Whenever possible, hold both threads. When only the top is available, hold it without pulling on it. Your thread clumping on the bottom in reverse is a mystery. Does the bottom look perfectly placed in forward sewing? What needle size and thread sizes are you using? How dense is the leather? What stitch length are you using? Check these things for top thread showing on the bottom: Top tension is too loose. Check thread to ensure it has not jumped of out the tension disks. If ok, increase top tension. Bottom tension too tight. Make sure the bobbin turns freely when loaded in the case and pulled firmly through the tension spring. If you feel an obstruction once per revolution, pull out the bobbin and cut off any starting thread stubs. Try less bobbin spring tension. Stitches are too close together for the size of thread. Use at least 6 per inch spacing, or longer, with #277 bonded nylon thread. Increase stitch length settings. Wait until the needle is just about to exit the leather before throwing it into reverse. Make sure there is between 1/4 and 1/2 turn clearance on the two spring loaded screws holding the shuttle race housing to the body. Move up one size needle. Make sure the needle is set with the eye facing sideways. If there is any lateral tilt at all, make sure it favors the direction of the oncoming hook. Thread might be too stiff. Try a different color to see if this is true. Not all thread is created equal and black is the worst offender. ;-)

The Cobra center foot has the tab on the bottom. Earlier Cowboy feet also had them, but don't any more.

My first Union Lockstitch Machine had some presser feet with concave extensions, ending in points, like a semi round. The purpose was to create rounded stitches with well defined hole ends. Another foot had a short blade in the front, which cut a channel as I sewed. This buried the thread below the surface. Both types of feet were only useful on straight line sewing. As soon as I turned a corner, the rounder or blade cut outside the stitch line. If you have a center foot for a 441 type machine, use it on straight stitch lines. Get and modify another center foot without the tab on the bottom for multi-directional sewing. Toledo Industrial Sewing Machines has smooth bottom center feet for their Cowboy 441 clone machines. I am certain that Cobra Steve or Techsew Ronnie will send a similar foot to their customers. I just saw some awesome looking custom made presser feet at Nick-O-Sew, for standard walking foot machines. They are called leather sewing feet and closely resemble the harness feet supplied on Cowboy and Cobra 441 stitchers. They work with any machine that uses "Singer 111" presser feet.

I always grind off that protrusion on the bottom of the center foot. Then I use Emory cloth on the edges, then buff to a high polish.

Using pre-lubricated thread on top makes it easier to pull up the knots, reducing the required foot pressure a bit. If you don't have this thread, but do have a lube pot, pour in some liquid silicon thread lube and run the thread through it. You may even be able to move down one size needle, further reducing the needed pressure. Experiment. On some jobs I will reduce both tensions. This definitely makes it easier to pull the needle up without lifting the leather. You would have to find the best minimum tensions to balance the knots, without leaving loose stitches on top or bottom. If you reduce the tensions on top and bottom and find that there is still too much upper tension with the top disk nut backed entirely off, change the thread path to straight through the top post instead of wrapping around it. You may also need to reduce the check spring tension to the minimum needed to return to the lower resting position. If you can't reduce the foot pressure with the adjuster almost off (because the spring is taller than the channel it rides in), remove the threaded pressure adjuster and coil spring and cut off a couple of coils. This will give you more turns in the almost zero range. Black bonded thread is usually double-dyed and is springier than most other colors. It automatically exerts more tension than other colors. White and beige thread is usually softer and easier to balance. If your 3500 shipped with the blanket foot set (with teeth), you can get the teeth filled in with rubber, dipping compound, or epoxy and use them instead of the harness feet. The wider footprints spread out the top pressure, reducing foot tracks in the leather, while holding down the leather between stitches. Just a thought. Finally, you can use a modeling spoon, teaspoon, or a rounded and beveled end of a bone folder to rub out foot tracks. I always keep a couple different nose shapes of bone folders.

Yes, reduce the pressure spring as much as possible, without allowing the material to lift with the needle. If there are still foot marks, order a pair of paddle shaped feet from Bob Kovar, at Toledo Industrial Sewing Machines (866-362-7397). I bought a right and left toe set from him. The right toe paddle foot is especially useful for sewing narrow flanges on holsters and cases, where the standard right foot would fall off the edge. If you back off the top pressure spring until it almost pops out of the head, it may be too strong. Bob also has lighter and heavier pressure springs. I have standard and heavy and plan to order a lighter spring.

Thanks Bob for your input. Note; on my CB4500, with the Family Sew motor, with its 2" pulley, feeding a 3:1 speed reducer, up to the machine pulley, for a total reduction of 9:1, there is no need to modify the pot or switch in the slightest. I already can sew at the speed of grass growing. Setting the switch to the slowest speed and pressing the pedal to the metal yields a steady top speed of one stitch per second. Even if I move the top speed position well up there, the slow speeds are still easy to attain.

The foot pressure is controlled by the long leaf spring along the back. There is a thumbscrew under the pivot axle on the top trapeze mechanism. That screw tightens or loosens the pressure as you adjust its position. There is a sliding regulator gib on the back of the presser foot and above it. There is a thumbscrew that secures the gib in place. Raise the foot with the hand lift lever, then loosen the screw on the gib, slide it all the way down until it touches the top of the foot mount, then lock it in place. That is the maximum stitch length setting. On a like new patcher, the maximum stitch length into 8 ounces is 5 to the inch. On a worn out 100 year old patcher you'll be lucky to get 7 or 8 to the inch into 8 ounces. If you find that the stitch length doesn't improve with the regulator gib all the way down to the raised foot, try wiggling the foot forward and backward. If it moves more than 1/16 inch, it is shot. If it moves between 1/64 and 3/64, it may be savable by brazing, shaping and polishing bronze welding rod material onto the inside "puck" that slides inside the round ring under the head.

Hydraulic clicker press, using steel rule clicker dies. The press weighs about 2000 pounds and operates on 220 v.

The motor starts at the slowest switch setting (350 rpm), once the brake is released. The pedal has a good range of speed control, from just over 1, up to about 2.33 stitches per second. I only use that setting on biker patches and phone/pistol cases. It is way too slow for anything else I do on that machine. The brake is needed to stop the machine from over-sewing on 10 to 15 sps jobs.

The changes are noticeable for each click of the switch. That is, until the last three, which do nothing more to increase the speed. The switch has been wired in backwards, with higher speeds counterclockwise and the lowest at full clockwise. The maximum driven speed at the machine would be about 1400 spm, or 23 per second, which is too fast for the machine. I get this by dividing the maximum rpm, which I think is about 3600, by 2.5, which is the motor to machine pulley ratio. My actual maximum sewing speed used would be about 10 to 12 stitches per second (under 800/minute), on long zippers or hem lines. I guess a top motor speed of 1800 would do just fine for me on this machine. The slowest speed I currently get is ~1.5 stitches per second (thin pouches, wallets, phone cases and patches). I would like to be able to get 1/2 stitch per second, steady pace, for precision sewing around curves and shapes on motorcycle patches. Right now I single stitch around these shapes, or hand wheel through them. Taking my hand off the work loses control over the vest. My vest patch machine is a 20" body Singer 139w101, compound feed, walking foot machine, with a 4.5" diameter machine pulley. The Family Sew motor has a 2" pulley.

I will do that next time I go into the shop.

Bob; Will your pot and resistor mod plug into my rotary switch on my FS550s? Or, would it replace the switch completely? Does this extend the slow speed below stock and still have enough torque to turn the machine over at under 60 rpm (at the motor)? Right now my FS 550, attached to a long body Singer 139 walking foot machine, bottoms out at 1 stitch per second, with 2.5:1 gear reduction from motor to flywheel. I cannot give up my top speed. Whatever mod I might use, it must still allow full speed when needed (3500 rpm?).

For a while, about a year ago, I had a problem with the top thread moving away from the center of the upper tension disks. I ended up using a drastic fix. Normally, you feed the top thread around a triple eyelet part, then into and around the tensioners. Since this wasn't hold that particular thread down all the way, I actually fed it under the steel spring pin on the right side of the tension disks, then up on the right and over. That absolutely cured the top tension problems. I had to back off significantly to compensate for the added tension from that sharp turn. Maybe this will help the O.P. Other things to check are scratches on the hook and the area that is beveled behind the point. Also, make sure the hook is very tightly mounted. Any looseness can cause issues. Check for thread remnants under the hook, in the shuttle area, or even underneath.

I have tested the Family Sew fs550s at work, mounted to a long body walking foot machine, having a 2.5:1 ratio between the motor and machine pulleys. The best steady slow speed was quicker than 1 per second; probably around 1.5 per second. The Sew Pro 500 definitely sews slower at a controllable pace, in a oranges to oranges comparison. If your motor has a 2" pulley and the machine has a 4 or 4.5" pulley, your results may be similar to mine. But, if the machine phulley is under 4" your minimum steady speed may be higher. Note: it is trivial to stop the needle up or down on the FS550 to do single stitching. I do that all the time around sharp corners and inside curves.

I researched the NakaJima 380 a bit and found these facts: It is a triple feed, light to medium duty, walking foot machine. It has reverse. It will sew with #138 thread top and bottom. It has limited sewing capacity under the lowered feet; just under 1/4 inch In contrast, a Consew 206RB-5 can sew into 3/8 inch of material

There are several members here that are modifying their FS 550 motors for better slow speed control. One person has plans to market the components after optimizing them. This would allow one to sew from 1/10th, all the way up to 50 or more stitches per second, with one dial setting on the motor. As for the Sew Pro 500GR, it has become hard to find.

I have a walking foot machine at home and a similar machine at work with each of those motors. The one at home has the Sew Pro 500GR motor and sews into denim jeans at about 1 stitch per second, steady pace. It drops out into single stitching when I try to sew slower. This is with the speed knob on full. It sews slower at about the 50% position on the pot, but loses top end. It groans loudly at the slower speeds, at 50% or under rotation. I am worried about its future. I'll try the same piece of denim at work, tomorrow, on the Family Sew 550s equipped machine. That motor is only one year old. I'll be back tomorrow afternoon with my findings. I have another FS 550 under my big Cowboy CB4500. It feeds a 3:1 reducer system, up to the flywheel. It can plow through hard leather at the astounding rate of 1 stitch every 5 or 6 seconds. Sometimes I hold it at that rate just to amaze myself and my customers. Watching thee needle move that slowly is like watching grass grow. The overall speed reduction from the motor to the CB4500 is about 9:1. On the walking foot machine it is 2:1.

You can buy a Family Sew 550s for $135.00 shipped.

To your knowledge, will your pot mod substitute for the rotary switch currently installed in my FS-550s? I already have great slow speed control, especially with the 3:1 reducer in the chain.

That Neel's number 5 is a good machine for saddlery, like you want to do It sews just under 1/2 inch, depending on how dense the leather is. It uses heavy bonded nylon and bonded polyester thread, definitely up to #346. The machine is bottom feed only, with aggressive feed dogs. As long as the bottom appearance isn't critical to your work, this machine is a decent alternative to a CB4500. What you will lack is a walking foot that climbs up and down new layers, triple - needle feed and a 16.5" arm. Those things exist on the model CB3200 and up.

My FS-550s has a rotary switch, not a pot. The slowest setting is full clockwise. It speeds up the wrong way, CCW. On the pot mod, is the slowest speed at the lowest resistance (~10 - 12k)?