Wizcrafts

Chapman asked if the Cobra Class 4 is good for thin material. Technically: yes; practically: not without certain readjustments. I have used a Class 4 owned by a fellow leather goods producer and own an identical machine branded as a Cowboy. These machines are built tougher than most sewing machines. They have massive castings and very strong pressure and tension springs. Their feed dogs are very large and have a gigantic needle hole that is more or less a slot. The cutout in the throat plate is very long and wide, to accommodate the full range of motion of the feed dog and its maximum stitch length setting. All this is meant to allow you to sew very dense and thick stacks of leather, or webbing, with most of the heaviest bonded threads in common distribution. So, what needs to be done to sew thin, soft material? You need to dumb down your machine. Here's how. For normal stiffness heavy broadcloth and denim (pants and shirts), etc: change to a #20 or 21 regular round point needle. Switch to #92 bonded nylon or polyester thread, or #80 or 100 cotton/polyester jeans thread. Load the bobbin with the same thread. When you install the bobbin, reset the spring tension on the bobbin case for a slight, but smooth resistance. Basically, it needs a little more pull that a domestic sewing machine, but nowhere near what you use to sew a half inch stack of veg-tan. Use the supplied open end wrench to loosen the nut on the back of the housing on the head for the shaft on the lower tension disks. There is a spring on the bottom shaft, known as the "check spring." It's job is to keep tension on the top thread as the needlebar moves down. It lets go just before the needle reaches BDC and reengages as the needle and take-up lever start moving up. The amount of travel can be set via the movable sliding steel stopper under the bottom of the spring. Normally, your 441 machine is adjusted with a lot of check spring tension, needed to maintain control of up to #415 bonded thread. It is waaaaaay too much action for #92 thread! After loosening the locking nut, use a screw driver blade in the split end of the bottom shaft and turn it counter clockwise to loosen the spring action. You'll want to back off the spring action so the spring has just enough tension to fully travel up and down to its stopper, and nothing more. Tighten down the nut behind the housing to lock in that spring setting. You may or may not also need to back off the nut on the front of the lower disk shaft, to allow the upper tensioner to control the position of the knots. Back off the upper tension disks nut and sew into a test piece of the same material and thickness. Keep backing off the top tension nut until the knots are buried inside the material. You may have to take it to zero tension. If you cannot back off enough on the top, loosen the lower tension disk tension with its round knurled nut. If the knots are just slightly on top, tighten the bobbin spring a little. Make sure the top thread feeds straight from the thread stand through just one hole in the top post. Doubling the top thread around that post can sometimes override the top tension spring in soft and thin materiel. As a last resort, move down one more needle size. You can go as low as a #19 needle for #80 or 92 thread. Smaller needles make tighter holes and help the knots to move down. Last, back off the presser foot pressure adjuster until it almost pops out of the housing. Hold back the starting thread in your left hand. Backtack over the first three stitches to lock them in. Sew at about 8 stitches per inch. Backtack 3 stitches or so at the end To sew soft and thin cloth materials (iffy) Switch to no more than #69 bonded thread. Polyester may work better. Install a #18 standard round point needle. Make sure the top thread has a direct feed path to the upper tensioner without doubling over any posts. Remove the throat plate and bobbin case, then unscrew the feed dog. Use a wide flat blade screwdriver and lots of torque (ccw). Install the optional flat throat plate with a narrow slot. Reinstall the bobbin case. Follow above procedures for reducing all tensions and foot pressure. Use the double toe harness foot, or even the wide blanket foot, if you received one. Balance the tensions as best as you can, with a minimum of bobbin tension. Install the flat table attachment for better material stability. Hold back the starting threads and sew forward three stitches Reverse and sew back over those stitches. Hold the material fairly tightly front and back and sew at about 8 or 9 stitches to the inch. Backtack at the end. These readjustments will technically allow you to sew cloth on your big 441 machine. The drawbacks are the time needed to do all these changes and parts removals and the walking feet with an open gap behind the inside foot. The huge feed dog and its throat plate can allow soft and thin materials to get pushed down into those openings. All these worries can be alleviated by using a standard industrial sewing machine for lighter work. You can even use a common household machine for light cloth and linings. They use much lighter thread and much smaller needles.

Once you get the timing problem corrected, it may be worth up to $500. You may have to replace the driving gear. Adler parts can be expensive! Otherwise, try dropping the racks and reposition the gear manually, to time it to the needle. Reinstall the racks so they move it in sync.

Chapman; You posted your general question in what is known as a sticky topic. Steve's tips for 441 owners was supposed to be his own limited discussion topic, not an open discussion. You should re-post your question as a new topic, in this section of the forum (but not this particular topic). Personally, I keep several machines, each with a different capacity. Smaller machines are for thinner work. Your Cobra Class 4 is not meant to replace them.

Look for a hole in the base on the front right side of the machine. If there is such a hole, you can insert a straight blade screw driver into an eccentric screw that moves the shaft that connects under the arm to the long rack gear. Unless the screw has rusted, or been Locktighted, it should turn freely. Doing so moves the shuttle. You'll want to either retard or advance the hook to arrive after the needle bottoms out then rises and stops. That is when the best loop is formed. If you are unable to correct the timing using the eccentric screw adjustment, the racks may be misaligned with the driving gear. Compare yours to the photo Constabulary posted.

When I mentioned "soft to medium temper" leather, I was talking about vests, chaps, motorcycle seats, dress belts, bridle leather and veg-tan leather projects that aren't made of hardened or dense leather. The tougher the leather, the higher the requirements for a suitable machine. An upholstery grade machine equipped with a #23 (aka 160) needle and T135 bonded nylon thread on the top and in the bobbin will have a hard time holding down thick or dense carving leather after it has dried thoroughly. It will also take a lot of tension on the top to pull the knots up from the bottom. The same job made of bridle leather may sew like butter, depending on who tanned it. If you intend to build gun holsters, knife sheathes, scabbards, armor, thick cases and such, a heavy duty leather stitcher will probably be required. These machines are typically referred to as class 441 machines. Examples are the big machines sold by Techsew, Cobra, Cowboy, Nick-O-Sew, Weaver and other dealers who cater to the leather trade. These machines must be modified by the dealers before they are ready to sew thick or dense leather with very heavy thread. My Cowboy CB4500 is usually threaded with #277 (T270) bonded nylon thread, top and bottom, and is capable of sewing over 3/4 inches (20 mm?). Your typical industrial sewing machine dealer will not sell such a customized machine for dedicated leather sewing.

Joe K; If you are looking for a machine to sew leather that is 3 mm in thickness or over (Canadian measurement), with any substantial size of thread, "cheap" may end up being well over $1200. The only manually operated machine in common use among our members is the Tipmann Boss. It sells for about $1400 USD. However, if you have arthritis affecting your right hand and arm, the Boss may be too stressful to operate (it uses a push pull lever on the right). We do have a section of the forum called Marketplace, which includes a section where people can sell used sewing machines. Boss machines show up very often. If you're looking to sew soft to medium temper leather, up to not exceeding 10mm, a decent upholstery grade walking foot machine may handle it. There are many machines in this class. The ones useful for leather sewing are triple (compound) feed walking foot machines. Examples are those sold by Juki, Consew, Chandler, Brother, etc. Singer used to make such machines, decades ago. The most widely used were the older model 111w155 and the newer 211w155. Either will take #138 (T135) bonded nylon thread. Check your local Craigslist, or equivalent, for businesses or individuals selling one of these in good working condition. Every upholstery shop, plus alterationists who sew denim jeans, use walking foot machines. Upholsterers usually sell off older machines as they buy new ones. You might pick one up for $500 to $700 in decent condition. Anything under that might possibly need parts or servicing.

The Singer 211 might do for you, as long as it has a triple feed walking foot system. Otherwise, the Mitsubishi 350 might work on your stuff. Note, it only has top and bottom feed, with a fixed needle and inside foot. The other machines look like bottom feeders only.

I suspect that your Boss uses the same 441 type bobbins my Cowboy CB4500 uses. I have obtained bobbins from 3 or 4 sources and can tell you with certainty that there is a dimensional variation in some of them. There are a few that are taller and actually protrude beyond the lip of the bobbin case. These bobbins have more tension on the thread than the shorter (normal) bobbins. If this ever becomes a real problem I can easily loosen the bobbin case tension spring a quarter or half turn while using the oversize bobbins. I don't think your situation should be any more complicated than mine. If a bobbin rides beyond the bobbin case, back off the tension spring a bit until the pull on the thread feels the same as on the shorter, normal bobbins. You would have actual trouble if the diameter of the top or bottom bobbin flanges was the same as the inside of the case. That would be Emory Cloth time for me, to reduce the diameter for a smooth revolving fit. Also, I believe that some of my bobbins are more curved on the outside of the flange than others. These would also have a tad more tension for a given thread and bobbin case spring setting. Unless the bobbin actually binds, it shouldn't be a deal buster.

Need I point out that part of the wear on patchers happens inside the drive ring and cam? It's not just the easy stuff that needs to be rebuilt. It depends on how the machine was used and abused. I recently replaced the driving cam in my k71 and the new part is different than the original. The action is not as fluid and binds in certain conditions. When I get time I will take the head apart and try modifying the new part. I bought a new shuttle driver and its gear, as well and the following gear and racks for my k172. The parts that actually fit bound up 100% in 1/2 revolution. The following gear wouldn't even go onto the shaft. I had to reinstall the old parts and use Locktight Blue to get the machine back into sewing condition. That was after dinking with it for two days. There is so much work needed to make some new parts fit like the originals did that it may not be worth the time and expense.

I own both a 29k71 and a 29k172. The 71 has a small bobbin and short arm, while the 172 has a larger bobbin and a longer arm. If you want a different brand, look for an Adler 30-7 or 30-70. Some folks own Claes patchers. Darren Brosowski also sells a unique type of patcher. I have seen the Cowboy patcher that is sold at Toledo Industrial. It is rock solid. He has a web page describing Cowboy patchers. Our other dealers also sell their brands of patchers. Ask them all about prices and warranties. Tis better to buy something new when going into actual production.

You can send the machine to Campbell Randall, in Yoakum Texas, to be rebuilt. I spent about $1000 in parts rebuilding my last Union Lockstitch Machine, just a couple years ago. New parts and tight clearances make a huge difference in the performance of these beasts. I was able to do the work myself, as I've owned two of them. If you have to send it to the factory, expect to pay out about $1500 to $2000 for a rebuild, plus about $300 shipping each way. Your first purchase, if you don't already own one, is the user's manual. It is a combination setup and adjustment manual and a parts book. Every single part is listed, including optional presser feet and throat plates. Also, unless you got at least three of the sizes of four sided internal adjuster T-wrenches, buy a set anew. The smallest is about 3/16 inch and the largest is 1/2 inch. Old bobbins tend to have suffered falls or other calamities. Buy some brand new bobbins. Old bent steel bobbins often have sharp burrs from people trying to straighten them out with pliers. A new bobbin is just $22 and should last a lifetime, unless you drop it on a hard floor. I had 10 for my last ULS machine. If your needles or awls are bent or rusted, discard them and buy new one. They sell for about $34 for a pack of ten. Use one number larger awl than needle. A #3 needle and #4 awl is the practical minimum for black #277 bonded thread. You can get by with a half size smaller if you use light colored thread. Buy every needle size you expect to need. I used to have every needle from 0 through 6 and every awl from #1 through #7. The 0 needles are as rare as Hen's teeth now. Consider yourself lucky if you can find some #1 needles. They work with 3 cord linen or #92 bonded thread. Sometimes you can grab #138 thread in a #1 or 1.5 needle. I used such a setup to sew rifle slings on my ULS, with #138 Weaver bonded nylon thread. Small hole = tight knots. Lax Wax is great, but requires the wax pot to be removed and cleaned out every so often. I like Ceroxylon just as well. These are used with Barbour's Irish Linen thread (left twist, glazed only). Campbell Randall stocks this thread in various sizes. Do not try to save money on the European linen thread. Buy Barbour's. Who cares if it costs almost $50 a pound? The results are worth it. Your machine can use 3 cord through 10 cord linen thread, run through liquid wax. Left twist only!

BigSmile; A Singer 66 is NOT a leather sewing machine. It is meant for sewing light cloth with thin cotton thread and tiny needles. The maximum stitch length is very small. The bobbin basket is not built to clear heavy thread, the presser spring won't hold down hard leather and the solid foot will drag the top layer out of alignment. How do I know? I have one at home and one at my shop, for sale. I rarely use the one at home, and then, only for very light cloth. It is a hobby machine.

If you should decide to go into leather repairs and sewing patches onto Biker vests, a patcher is indispensable. I have two in my shop: a long arm large bobbin and a short arm small bobbin. Both have little 1.5 amp motors and foot operated speed controllers. Both need to be started by hand before the itsy bitsy motors can take over. Why a patcher? Because of the very narrow cylinder arm, a patcher can sew a patch over a pocket and get very close to the sides or bottom. No other machine in my arsenal can do that. Due to the 360 degree presser foot feed, a patcher can follow the shapes of the patches or seams as you sew. Of course, this takes away one hand. Patchers can get inside purses to repair tabs that are pulling off. They are especially good at replacing zippers on purses, or on leather jacket pockets and sleeves. The machines can get well into the vamp of a shoe to go over loose or missing stitches. In short, if you need to sew in very tight quarters, with thread not too thick, into material not exceeding 1/4 inch, and possibly in more than one direction, nothing beats a patcher!

I bought the same parts from Toledo Industrial Sewing Machines. 866-362-7397.

As pcox mentioned, the shuttle hook can be moved laterally, as well as forward or backward. Plus, the needlebar itself has some lateral adjustment via the long bolts that go through the moving arms on the fore and aft of the body. Some causes of missed stitches, or cut thread, are, in no particular order... A burr on the bobbin cover; A sharp leading edge on the bobbin tensioning spring that is mounted on the inside bobbin case cover; Too much tension and not enough clearance for the top thread due to that spring being set too close with no wiggle room; Twisted thread on the barb of the needle (various causes and fixes); A bent needle (believe me, it happens); Top thread being held too long on the needle down cycle. This can cause the thread to stay on the needle and get caught in the bobbin drive gears. It can be caused by a wrong too long setting for the slack takeup lever that holds the thread back as the looper feeds the needle. Bad thread can happen. I always operated my ULS machines with the bare minimum of clearances necessary to sew smoothly and consistently. A properly tuned ULS can sew flat out at 15 stitches per second, until the bobbin runs out. Wear earplugs before doing this!

Most of the thread used in modern day leather stitchers is bonded and often lubricated. It resists most of the leather dyes. Fiebing's oil dyes may penetrate white bonded thread better than other dyes. When I had my Union Lockstitch machines I used Barbour's glaced linen thread. It was available in natural, white, brown, yellow, or black. Any of those lighter colored linen threads could be dyed darker after sewing and the color held fast. If you care to experiment with glazed linen thread, start by getting a Union Lockstitch, or Campbell Randall Lockstitch machine. Or, most shoe sole stitchers use linen thread.

Unless you are doing tailoring, the serger will be of little use to you. You should contact any dry cleaners or tailors, or seamstresses in the area and see if you can off load it at cost. Sergers like yours don't sew leather, just soft cloth. Their purpose is to cast a tight layer of thread over the edge to prevent the material from fraying.

I use a serger when I hem cloth pants, skirts, etc. If you tune it up and sharpen the blade, it will lay down a nice overcast stitch on denim jeans.

Be aware that parts for these ancient Singer 45 types are few and far between. Make sure you know what you are getting into. Missing screws may have to be custom turned.

All of the missing parts are available as aftermarket items. They may or may not fit without modifications. If you can locate old used, but not abused parts they may fit better and work with less binding. I tell you this from personal experience.

Bridles can be really thick on certain areas of the straps. I repaired one yesterday that was about 5/8 inches thick. Neither the 2500 or 3200 would have sewed that thickness as easily as the CB4500 (if at all). Anybody sewing horse tack for customers is bound to encounter these really thick junctions. But, if your Son will be only making his own tack, he can limit the thickness to what the machine can handle. As for a good learning machine, the forward feed only CB2500 will force him to learn the Poor Man's Reverse. Then he can learn to smooth out the tooth marks and needle hole puckering on the bottom.

Yes, tacky cement can cause skipped stitches. Ditto for Venture leather tape. Since I use the tape a lot, I switched to titanium coated needles on both patchers and on my long body Singer 139 walking foot machine. Unfortunately, there aren't any available for the big 441 clones yet. You may be able to compensate by using lubricated thread.

Nice work! I'm not surprised that the Consew handled it this well.

Sometimes the simplest errors in reassembly can cause the biggest grief to the sewer.

You should ask Cobra Steve what size bolts they're tapped for. He may even have a pair of bolts.