How Do I Use The Strap Plate W/o Feed Dog To Sew Tack On My Cobra 4?

[Oak Grove Leather Works]

Good morning! I have been using my Cobra 4 to sew holsters and knife sheaths for a little while now, and I just got induced to start making horse tack. The Cobra 4 instructions say to remove the feed dog and install the narrow slot needle plate, along with the adjustable guide wheel. I have done all that and when I try to sew, the leather doesn't move. I'm sure the solution is something simple, since this is a popular machine, but I'm not sure what to do. The machine comes with a holster plate, which I tried some time ago with the same results and a stirrup plate that I haven't bothered to mess with. I am hoping somebody out there can give me some hints on how to make these accessories work.

Thanks for any advice!! -Steve

[dbusarow]

Even without the feed dogs you still have the walking foot and the needle which are both moving the leather. The only thing I can think of is that you have the stitch length arm in the center position.

Dan

[Oak Grove Leather Works]

Thanks for the reply. I have the machine set for about 8 stitches per inch, so that's not it. I'm wondering if I just need to crank up the walking foot pressure. I didn't change that at all.

[jsmith]

Try going to 6 or even 5 spi until you get the stitch you want.The # wont match up with where you have been running it.

[JLSleather]

The 'cobra' foks can't tell you? I heard wonderful things about the 'customer service' there ..

[Oak Grove Leather Works]

The 'cobra' foks can't tell you? I heard wonderful things about the 'customer service' there ..

I haven't heard back from Steve, yet. I may have to call him.

Try going to 6 or even 5 spi until you get the stitch you want.The # wont match up with where you have been running it.

Well, the issue is that the leather doesn't move at all, not that it doesn't move the right amount. If I don't pull the leather along a bit, all the stiches go in one hole and jamb up the bobbin hook. I'm giong to try tightening up the foot pressure.

[Wizcrafts]

Back off the pressure spring until the material moves with the needle. Make sure you have just enough pressure to keep the leather from lifting with the needle.

Also, use one size smaller thread in the bobbin. If you have 277 on top use 207 in the bobbin.

Examine the slot in the throat plate for burrs or sharp edges and Emory them smooth.

Edited February 15, 2013 by Wizcrafts

[Oak Grove Leather Works]

So... Hours later... It was indeed the stitch size. It is now cranking out 8 per inch nice and smoothly. A little tension adjustment and it will be fine. Thanks for the suggestion.

[JJs Leatherworks]

I am still learning all about my Cobra 4 and this was an issue for me as well. You definitely have to play with the tension when switching the plates and removing the feed dog and the SPI you get with the feed dog will not be the same as when it is removed without playing with the stitch length adjustment. I have started keeping track of settings used for each plate to make it easier when switching back and forth for different projects and then doing a quick sample in appropriate thickness of leather before putting the 'good leather' under the needle.

It's a big learning curve, but as you learn the tricks, it is a great machine to sew with.

JJ

[Wizcrafts]

As JJ mentioned, the stitch length changes when you sew without the feed dog. What many don't expect is that the reverse stitches no longer match the forward stitches, at the old settings of the feet. I find that it is possible to dink with the point in rotation where the needle and inside foot makes contact with the leather, to almost balance out the differences. This is iffy at best, so I usually just watch where the needle is about to hit in reverse and pull down a little on the stitch lever to compensate if too long (reverse is usually longer w/o feeders).

[Oak Grove Leather Works]

Thanks for all the advice. It will certainly steepen the learning curve for me. I made a headstall and you can see my work improve from ring to ring. I'm going to have to replace most of it with better stitching, but it could be worse. It could be raining.

[Cobra Steve]

Hi folks. This is for anyone who owns a 441 clone type of machine. When using the slotted plate, holster plate, or the stirrup plate, you have to remove the feed dog, add stitch length, and in some caes increase the foot pressure. When sewing without a feed dog you have taken away half of the feeding and to compensate for this you must increase the stitch length until you achieve the desired look. Thanks, Steve

[art23]

Hi Steve . Are there any repercussions if you use the slotted plate, holster plate, and the stirrup plate and you do not remove the feed dog. Is there any type of damage that can occur?

[CowboyBob]

If you leave the feed dog in when trying to use these needle plates it will hit the bottom of the plate & either break some major part or just bind up the machine.

[BigJake]

I have a C4 machine and this is what I've learned and some of this may be of benefit to the OP. The text in blue is from another post which I describe some of the problem.

I have the same problem with my C4 machine and it's about the top thread tension. Put about 1/4" of leather in your machine and turn the handwheel very slowly and look closely at the needle/presser foor interaction. You might take off the dust cover off and also watch the thread as the stitch is picked up. When the hook picks up the thread the needle is on the way up and as the hook rotates on around pulling thread through the needle and top thread tensions, observe what happens. The top thread is pulled toward the front of the machine and at the same time the needle is pulled/bent toward the front of the machine along with your product because the needle is still in the product. The high tension will cause the product to slip under the pressor foot, which is effect shortens the stitch length. The thicker the material being sewed, the more top tension, therefore shorter stitches. I also expect that when you are backstitching the needle is not going in the same hole. That's because to compensate for the above issue if you want 6 STI you will need to set the machine for 5 STI. When the lever is reversed there is no p[roduct slipage under the presser foot and therefore you will get 5 STI on the backstitch.

Take a scrap piece of 8oz veg tan and stitch without any thread in the needle. The stitches will be longer than when thread is used. Is there a fix for this, which I'm sure is a top tension issue? I don't know. I do believe that haveing the front of the walking foot or needle foot cut out adds to the problem. When I sew 1/4" of veg tan using 277 thread top and bottom and a 25 needle, the needle will be bent forward completely into the cutout. The other heavy stitchers like the Ferdco and Juki 441 I've seen, don't have this cutout. Just a round hole for the needle to pass through. This round hole would prevent the needle from coming forward nearly as much and I believe would solve much of the problem.

This is follow up info I've learned since then. I basically sew cowboy gunleather using veg tan leather in 9/10 to 12/14 oz and 277 nylon thread top and bottom and a 25 needle. I mainly use the holster plate and the feed dog with the teeth on it, (don't know what it's called). This feed dog has a smnall round hole for the needle to pass thru and the small hole is the reason I use it. I know the manual says to remove the feed dog when using the holster plate, but on my machine the feed dog does not hit the plate at any time. Without the feed dog the thread and the needle will be pulled forward just as the needle is about to clear the leather and the shuttle hook has picked up the top thread and is pulling the thread forward along with the leather,the stitch length is shortened due to the material moving forward under the pressor foot. This also causes the stitches not to match when reversing the stitch.

Having three different type of needles and all have the same issue which is the needle below the scarf is back to normal diameter but with no slot to recess the thread the top tension is thrown off by this increased tension as the needle is about to clear the leather. Having the feed dog with the small round hole forces the thread to be pulled in a more straight down pull and does not pull the needle forward or the leather and therefore the problem. Increasing the pressor foot tension to the max did not fix this problem. Only adding the feed dog.

This issue is very difficult to explain in text and I hope this explanation is clear. Turn your machine over by hand very slowly and carefully watch the leather, the needle and pressor foot and interact, if you have this problem, you should consider what I've tried to explain above.

[BigJake]

My previous post need correcting. The OP was about STRAP PLATE and somehow I got HOLSTER PLATE and my comments were pertaining to the HOLSTER PLATE. The strap plate is not as tall and I'm certain the feed dog would hit the plate. Sorry for the confusion.