CB4500 vs Cobra C4 on thin leather

[Brazo]

Most responses here to the question of a Cowboy 4500 vs a Cobra Class 4  seem to be along the lines of "choose the color you like best" or "which dealer is closer to you". However, I have seen a few posts indicating the CB4500 handles thin leather a little better than the Cobra. Can anyone comment on what the machine differences are that would allow this to be true? Or is it just a result of the skill levels of the operators in setting up their machines?

Edited January 28, 2019 by Brazo

[Ferg]

I cannot answer for the 4500, I have a 3200 and I am going to assume that since the operation is very similar in the two models....

I find the thin leather falls into the feed dog space/hole and distorts the leather you are sewing. I have a small slot needle plate which has another problem. Thin leather doesn't slide over the plate easily without more than normal foot adjustment pressure thus making marks in the leather face.

Bob Kovar suggested placing a piece of silicon tape on the needle plate so the leather would slide more easily. I haven't done that as yet. I just don't stitch thin leather on the 3200.

Ferg

[Wizcrafts]

2 hours ago, Brazo said:

Most responses here to the question of a Cowboy 4500 vs a Cobra Class 4  seem to be along the lines of "choose the color you like best" or "which dealer is closer to you". However, I have seen a few posts indicating the CB4500 handles thin leather a little better than the Cobra. Can anyone comment on what the machine differences are that would allow this to be true? Or is it just a result of the skill levels of the operators in setting up their machines?

Both of these machines are known as 441 clones and are equally caapable. They are clones of the Juki TSC-441, from around 1988 or '89, which was marketed to companies sewing buffing wheels, heavy webbing tow straps and leather harness. The 441 had a huge double toe presser foot, a wide inside foot and a wide feed dog, all of which had teeth to grip the material. The machine used needle sizes 23 to 27, covering thread sizes 138 through 415. Most users threaded it with #346 thread. It was never expected to be used to sew thin material with small needles and thin thread. For that they made the LU-563, which I had.

The Cobra and Cowboy 441 clones have a different type of foot design that is geared towards saddlers. It is known as the "harness foot set." The outside presser foot is about 3/8 inch across and the inside foot is just under 3/16" wide. Because the machine was cloned from a TSC-441, the feed dog is still very wide and has a wide, long hole for the needle. This extreme needle hole is needed because the feed tolerances allow quite a bit of range off-center as the feed dog moves forward and backward at different stitch lengths. Aerospace tolerances would solve that problem and allow for a more rounded hole, but that isn't the current state of affairs. Further, because the 441 clones are expected to be used with thick threads, up to #415, they have to allow for needles from #23/160 (for #138 thread) up to a #27/230 (for #415 thread), which is about the diameter of a roofing nail. So, you have a long and wide hole/slot inside a very wide feed dog that rides inside an even longer and wider rectangular slot in the throat plate.

Thin and/or narrow straps are easily pushed down into the throat plate slot and sometimes the feed dog hole. Backing off the foot pressure reduces the tendency to push the material into the slots, but is just a stop gap measure.

My solution is to remove the feed dog and change to the optional slotted throat plate and back off the presser on the feet to lessen the drag on the throat plate and foot impressions on the top grain. This takes about 10 minutes to change over. Better still would be to use a smaller machine to sew anything under 8 ounces, with thin thread and small needles. I have a bunch of such machines in my shop.

Your Cobra and Cowboy dealers sell a slotted throat plate, which is already included in the deluxe accessories package.

If you are going to sew as part of your business model, plan on buying more than one type of sewing machine. There isn't one that is equally adept at sewing from a few ounces up to 3/4 inch or more.

[Brazo]

Thanks for all the info Wizcrafts and Ferg. I have a Juki LU-1508N that I use for making bags, pouches and outdoor gear. I have used it to sew some thin leather and will continue to do so. I use 69, 92, and 138 thread in the 1508 but mostly size 92. As I get more into making leather items, I have a need for a larger machine. But sometimes sewing the thin stuff I need a cylinder machine. That's what prompted my question. For the occasional time I need a cylinder machine for sewing a peculiar type bag or something, I was hoping my new big leather machine, say CB4500, could be used with size 92 (or 138) thread.

Edited January 28, 2019 by Brazo

[Wizcrafts]

4 hours ago, Brazo said:

But sometimes sewing the thin stuff I need a cylinder machine. That's what prompted my question. For the occasional time I need a cylinder machine for sewing a peculiar type bag or something, I was hoping my new big leather machine, say CB4500, could be used with size 92 (or 138) thread.

Okay, I Grok you now.

Sewing thin material on a 441 clone requires you to dumb down the machine (read my blog article). This involves lessening all tensions and pressures. It also calls for some thin needles that are really easily deflected. In a nutshell, you need to spend 20 minutes or so changing settings and tensions in order to be able to sew 6 ounces or less with 92 thread with a #19 needle. I do this when I hem chaps, jeans and work pants on my CB4500 (because I don't currently own a medium duty cylinder arm walking foot machine).

[Brazo]

1 hour ago, Wizcrafts said:

Okay, I Grok you now.

Sewing thin material on a 441 clone requires you to dumb down the machine (read my blog article). This involves lessening all tensions and pressures. It also calls for some thin needles that are really easily deflected. In a nutshell, you need to spend 20 minutes or so changing settings and tensions in order to be able to sew 6 ounces or less with 92 thread with a #19 needle. I do this when I hem chaps, jeans and work pants on my CB4500 (because I don't currently own a medium duty cylinder arm walking foot machine).

I read your blog post. Good stuff there. Whenever I have to adjust tension, I usually use different color threads for top and bottom when making the adjustment - makes it easier to get the knot buried in the fabric.