Sew #69 Thread On My Cobra 4?

[Squilchuck]

I assume I can sew #69 thread on my Cobra 4, but I am not sure of the correct needle - something like 110/18 or 120/19? I usually use 794S or LL points with larger thread and needles, but I cannot seem to find a source for this needle system and smaller size. Any suggestions on size and supplier?

[Art]

Chuck,

You will be trying to do something that machine was not designed to do. The smallest 794 system needle in a leather point is a 160/#23 and the smallest I know of in a round point is a 140/#22. The smaller the needle diameter, the farther away the hook is from the needle. This can be adjusted (with some work), but you really shouldn't go screwing around with those adjustments over and over. The good thing is that you will wear out before the machine. The 160/#23 needle will work fine with Z-138 and Z-207/Z138 for a tighter stitch. You could use Z-69 with the 160/#23 needle, but the holes will be huge.

The best way to solve the problem is to purchase a CB-227R.

Art

[pcox]

I have sewn with 69 thread on that class machine. I use 7x3 # 18 needles but I had to change lots of adjustments . Needed lighter tension springs and change bobbin tension. Those long skinny needles flex a lot as you go over seams etc so you are going to break some needles. I didn't think it was worth the trouble. As said above maybe time for another machine.

[Wizcrafts]

The practical lower thread limit is really #92, top and bottom. Use a #20 needle with it

As mentioned already, there are no leather point needles in stock below #23 in system 7x4/794. Getting smaller leather point needles would require placing a very large minimum order with the needle manufacturer.

If your Cobra is already set up for #277 thread and sewing normally, you will have to reduce the tension to almost nil on the top disks and the check spring. Balance the knots using the bobbin tension spring. The travel of the check spring may also need to be dinked with to get a suitable loop at the eye of the needle on the upstroke. Of course, the top pressure spring will need to be adjusted almost all the way out.

Sewing things that look best with #69 thread may indicate that some of the material if very soft and thin (4 ozs and under). Such materials tend to get shoved into the huge slot in the throat plate and feed dog. So, it is best to remove the feed dog and standard plate and replace it with the optional flat slotted plate (with a narrow slot).

[Darren Brosowski]

You are using a sledge hammer to break wallnuts.

[Squilchuck]

Thanks for all the good feedback. You all confirmed my suspicion that the Cobra 4 is not designed to sew such lighter leather, which I rarely do anyway. I definitely don't want to have to fiddle excessively with tensions etc., not to mention deal with broken needles, then try to get back to my normal working settings. I'll work on a different solution - machine etc.

[Cobra Steve]

We sew with thread sizes 69-415 on all Cobra Class 4 machines, yes you will need to change the needle to a size 20 and adjust tensions, but it will do it.

By the way, I am back from my 3 surgeries in 10 weeks and I'm as good as new!

[Wizcrafts]

We sew with thread sizes 69-415 on all Cobra Class 4 machines, yes you will need to change the needle to a size 20 and adjust tensions, but it will do it.

By the way, I am back from my 3 surgeries in 10 weeks and I'm as good as new!

Welcome back, Steve! I'm glad you survived the butchery.

[Cobra Steve]

Thanks Wiz!

[Wizcrafts]

To be fair, I have managed to get a Cobra 4 to sew with #69 bonded nylon thread. I used a #19 needle, which was the smallest I could get at the time. I reduced all tensions, including the check spring. Finally, I had to remove the feed dog and throat plate and install the narrow slotted plate in its stead. With minimal top tension, I was able to sew a canvas bag and a zipper in a vinyl jacket.

The time it takes to transform such a machine into a light duty stitcher is only worth it if you only do it once in a great while. It is simpler for those in business to acquire other medium and light duty machines for thin, soft materials.

[Art]

I once paid $20 to watch two porcupines screw, but I can't say I would ever do it again.

Art

[Massive]

I just bought a singer 153W102 to sew thread in that range with 135 system needles. I have the cobra 4 set up for 277 thread, and figured I could get it to work with 69, but the main thing that deterred me was just that the needles are so long they will struggle with drawing up the thread. They are still long enough to do the super deep work that the machine is designed for so that means a long run of light needle going up and down, and also trying to needle feed. Just because one is running lighter material doesn't mean it will be a breeze to feed, so the needles could come in for a workout, then it needs to draw up the tension. I would rather do either with the 153 and 135 needles, which are dead cheap and plentiful in the sizes we need for these lighter threads. I hope I made a good choice, as I don't really know anything about the 153 directly.

[Massive]

One thing I do with my bobbin cases on other machines than the Cobra (because they don't seem to be removable, and anyway, are probably expensive). Is I get a weight that pulls a length of thread through the tension spring when I hold the case in my fingers with the thread running with the weight straight to the floor, not taking some bend around the spring. This allows me to return the spring tension precisely to the perfect setting for various threads. I have been chasing a setting and got all messed up, though getting back is no big deal if one has a good system. However it makes me happy to know I can regulate the bobbin tension to factory specs and start all over even though it isn't marked. I sometimes mark the bobbing screw slot with a sharpie to know where to return the setting to, but the mark usually dissolves away eventually. However it works for a brief walk to the wild side.

With machines that use cheap cases I set several up for different threads. For instance the Sailright I have does some domestic weight sewing and some heavy sail sewing, so 49-90ish threads. 69 is in the middle and can run out of either setting extreme. But I did get in a muddle when I chased the promised domestic sewing end performance when the machine comes set-up up for heavy leather and sail type work (heavy leather over dacron, not holster type heavy).

I recently sewed some jeans on the sailright that were using 18 needles and heavy Jeans thread, into very densely woven Board Short material. What a set of Frankenstein settings that took. Sometimes you can't avoid breaking the whole the whole thing down.

A lot of the nice new machines these days we are told do not need bobbin case adjustments and stuffing a heavier thread under the same spring as a lighter one will to some extent regulate tension anyway, the heavier thread needs more tension, and that is what it gets under the same spring. It works up to a point.

[Squilchuck]

Steve, great to hear you are back in action. I did no see you Friday at Pendleton show and wondered why.

[CowboyBob]

Steve,

Glad to hear your back BUT I didn't know you were in the hospital.

Hope you mend up quick !!

[Cobra Steve]

Thanks Bob and Squilchuck! By the way, quite a day in San Bernardino on Wednesday. 5 miles from my house........too close to home!

Edited December 4, 2015 by Cobra Steve

[Darren Brosowski]

Steve I have run a 441 style machine on #69 and yes it can do it.

For someone who is going to run 69 or 138 on a regular basis then I really think they should look at having a seperate machine set up for the job.

I treat sewing machines like any other tool. Yes, one hammer will do any job but a range of hammers is more versatile.

We sew with thread sizes 69-415 on all Cobra Class 4 machines, yes you will need to change the needle to a size 20 and adjust tensions, but it will do it.

By the way, I am back from my 3 surgeries in 10 weeks and I'm as good as new!

[Cobra Steve]

I couldn't have said it better!

[SantaFeMarie]

The time it takes to transform such a machine into a light duty stitcher is only worth it if you only do it once in a great while. It is simpler for those in business to acquire other medium and light duty machines for thin, soft materials.

What would some examples of good choices for light dutry stitchers for a leather shop be?

[Art]

Marie,

For "light" duty, a Juki 5550 class of machine, but most "duty" around the leather shop is really medium duty such as is accomplished with the Cowboy CB-227R or the Techsew 2700. These machines will also cover the "heavy" end of the light range of needles and thread; e.g. #14/90 needles and Z-46 thread.

Art

[25b]

I use a Sailrite LSZ-1 for my light-duty parts of projects and a CB3200 for heavy duty use when the bottom stitches won't be able to be seen.

[Wizcrafts]

What would some examples of good choices for light dutry stitchers for a leather shop be?

Let me describe my operation and how I use different machines to sew different parts of a project.

Most members in this section of the LWN are very familiar with the concept of sewing heavy and thick leather on big stitchers with large needles and thread to match. But, not every job can be sewn on those machines, or with heavy thread. You cannot hide the lockstitch knots from #277 thread inside 6 ounces of leather or denim. Also, the big 441 and 205 type machines tend to eat thin and soft material inside the hole in the feed dog and stock throat plate.

This is were we must obtain lesser machines to sew thinner materials with thinner needles and thread. These machines can be both walking foot and straight stitch machines for general sewing. You are going to have serious trouble sewing together a satin lining of a leather skirt, or jacket, or a vest, on a walking foot machine. The material is extremely thin and requires common household sized thread and a tiny needle with a round point. A tailoring machine is best suited to this work.

I have a Singer 31-15 tailoring machine that I use for linings and cloth garment repairs. It can use the thinnest of threads, all the way up to #69 and sometimes #92. The feed dog and throat plate can be replaced with sets for light, medium and heavy materials. It can produce stitches up to 5 to the inch, or down to almost zero. Put in a #10 or #11 needle and #33 thread and a roller foot conversion and you can sew patterns onto cowboy boot uppers. Switch to a heavy feed set, a #18 needle and #69 thread and you can sew wallets. Change some springs and you can probably get it to sew chaps with #92 thread, using a #20 needle.

With all that versitality, it still has trouble sewing over seams, like on denim jeans. That is where you need to cross over to a walking foot machine. It will have higher clearance under the alternating feet and will climb over and back down seams reaching 3/8 inch in thickness. Your straight stitch machine probably cannot do that. Further, the walking foot machine has a different shuttle and bobbin system that allows it to easily sew with #138 thread. Most can be adjusted to handle up to #207 on top, usually with #138 in the bobbin. You would use this machine for everything too heavy for the straight stitcher and too light for your harness grade machine.

Big harness and holster sewing machines are not designed to be nice to thin materials. They often don't have leather point needles available in sizes under #23 (160). The feed dogs have large holes to clear huge needles and thick thread. GA1-5 type machines have a giant feed dog with serious teeth. It will eat thin material and seriously mark leather on the bottom, if the grain side is down ( as in double leather pouches, cases, belts and straps).

When it comes to sewing thick leather, you need a more powerfully and strongly built 441 and 205 type machine. They have beefed up parts and springs, needed to hold down thick leather and tow straps that are sewn with needles the diameter of porch nails. While you might be able to dumb down these machines to sew with thin thread and needles, into thin material, the time spent readjusting them back and forth may not be worht it if you have a busy shop. Besides, it's fun to watch your customers' expressions when they see a shop full of big sewing machines!

Edited December 8, 2015 by Wizcrafts

[Cobra Steve]

You are exactly right Wiz. Marie, we also have the machine that you need.

[Darren Brosowski]

Between the 15-91 and a walking foot is the pure needle feed machine. They are built on the same frame an industrial straight sewer and can pretty much handle all the work of one but they have a much more delicate touch that a walking foot machine.

In a perfect world everyone would have 10 different machines on tables but always remember than many machine heads fit in the same hole.....