cobra 4 Cobra 4: Presser Foot, Needle, and Bobbin Problems

[Philip Crabtree]

I bought a Cobra 4 a couple of months ago.  It's brand new and needed a little adjustment when it arrived to get going.  Things were going great until three weeks ago.  When I returned from a convention in Texas, problems ensued forcing me to hand stitch the projects I have waiting.  I contacted Steve, but we don't have a resolution yet.  Here are my issues I can use help with.

1. Presser Foot:  It is coming up as the needle is traveling upwards at the end of stitches.
2. Needle:  Bending on shuttle and breaking.  I've had to force the needle up higher to see the end in the window.  I've been using channel locks and a lot of elbow grease to get it done.  This cannot be the best way but is necessary.
3. Bobbin:  I can pick up the bobbin thread with my needle when initially change out the bobbin, but after that, nothing.  I find myself just poking a lot of holes in my leather rather than stitching.

I'd be grateful for any assistance.  I have projects customers are waiting on, but I'm having to hand stitch everything from chinks to holsters, saddle skirts and harness.

 

Thanks,

Philip Crabtree

www.CrabtreeSaddleWorks.com

[Ferg]

Philip,

I don't have a Cobra but I know many folks have them.

I believe you are going to do one of two things, return it for adjustment, have a sewing machine mechanic that knows how to work on industrial machines, look it over.

Steve is always good to help folks that have trouble. Give him another shout. You will probably need to start from the beginning of the adjustments.

BTW: Are you certain no one attempted to use the machine while you were gone?

Ferg

[jfdavis58]

I have a cobra 4.  Out of the box-or rather right off the shipping pallet it ran like it was charmed.  And I've managed to screw it up a couple times; still one thing always works as a fix: Start at the beginning.  Pull all the thread out, remove the needle and start over.  I usually run the machine very slow but if I start over I run it at a crawl when first starting, so set the servo for it's slowest speed too.  This start over exercise seems almost trivial, takes a few moments of intense concentration and one must use/read the manual so send everyone away and just do it.  It has never failed me.  Pay particular attention to rights and lefts and don't add in any specifics from personal experience -like say changing he kerf angle a bit.  I know anecdotally that when it does fail someone and they call Steve, it's where he starts nearly every fix not specific to some broken part(s).  Same goes for adjusting the thread tension (a bit of a recurring issue)-start from the neutral point found in the manual and make baby steps.  I try to keep in mind that this is a 'production' machine-made for an assembly line.  Made to be adjusted to one task and then run until it doesn't.  Then cleaned and readjusted first to the beginning point and then to the specific task.  And usually this adjustment is done by a specialist.  Good luck!

[Ken G]

Sounds like you have your needle to hook timing out of whack. Al Bane has several very good youtube videos online. One is a quick check of needle to hook timing inspection. His instructional video of the Cobra Class 4 shows the adjustment of needle to hook timing around the 28:35 mark. Search youtube for "Al Bane" or "Cobra Class 4" to find them.

[Northmount]

If the leather is lifting with the needle, and pulling up the presser foot, you need more pressure on the presser foot to keep it down.  A different batch of harder leather could have done this to you.  Also, a larger needle can do it too.

Don't leave any plier marks on the needle or anything in the thread path, else it will snag and damage the thread leading to what appears to be tension problems, and birds nests under the feed dogs and plate.

As above posts mention, pull all the thread out and clean up around the bobbin and hook, then rethread carefully to make sure it is done right.

Tom

 

[Uwe]

Make sure you use the right type of needle (794). The needle should slide easily into the needle bar before you tighten the set screw.

These two videos should cover most setup and adjustment issues. Watch them in their entirety and compare your machine's settings with those shown in the videos.

 

 

Edited May 1, 2016 by Uwe

[JLSleather]

I had a video on my computer at one time, must have deleted it after deciding it wasn't my responsibility to answer for questions from someone ELSE'S customer

But, to spare you the pain of enduring over an hour of what-have-ya over a simple question, we'll use this one. Well, actually, a small sliver of this one.  FF the second video to about 14:30 on the time (slide the red dot on teh timeline).  This will show you the "end view" of that machine so you can quickly tell if your problem is in the timing of the needle.  No need to turn on the machine and shatter something, just turn the wheel by hand.

Note the position of the needle and the the position of the shuttle and presser foot (you can turn the sound off it you like, may help).

Looks like about 14:32 the needle is about bottomed out.  The hole in the needle is a little lower than the hook.  The hook is rotated left and the (outer) presser foot is coming up (center foot coming down with the needle). Continuing, the needle begins to rise and the hook rotates clockwise until about 14:34 the hook arrives to pick up the thread and the presser foot is all the way up. By 14:37 the thread is sweeping the hook assembly and the presser foot is down again

[JLSleather]

Incidentally, if somebody got this same view on a Cowboy machine and cares to send it, I'll put it on my site for FREE viewing by all. 

[Uwe]

The pain levels caused by a non-functioning machine your business depends on may be higher than the pain of watching some essential instructional videos that help you understand how the whole machine works.

I think it's useful to use common terminology regarding needle anatomy. There's a "scarf" on a needle, but no "kerf". "You know what I mean" doesn't really work for beginners who are trying to learn. 

Anybody planning to rely on remote, internet-based tech support for their machine is also well advised to quickly figure out how to take sharp, well-lit photos and video snippets with their smart phone, and how to share video snippets with others on youtube, either privately or publicly.

In the absence of overriding clone manufacturer instructions, the original Juki Engineer's manual for the TSC-441 class of machines is the authority on adjusting these machines.

[Darren Brosowski]

This sounds odd to me as it appears the machine was working and then it wasn't.

Something changed.