a Tension distraction

[brmax]

Hey you all with my cobra4 craigslist find I picked up earlier this year, I didn't have to tune much at all with it and kept with the 277 thread size though replaced with poly.

I did find replacing the old spool of thread did everything I had issue with in the stitch tension issue, off n on every 3".  I'm positive it had a catch in the spool somehow so not being any particular type thread thing. 

So anyway getting a few more chances to put some leather under it, I have found with some earlier adjustment. Here goes, that even though I have top tension backed off and flush with thread end, seriously.  Lower tension knob a thread from being flush, the machine with some tuning sews good with what I been messin with 5oz to 5layers of 8oz with just messin around stuff.

My gripe is, in a sense if I have any  The shuttle tensioner, screw is tight and I actually have no adjustment (knock on wood) as mentioned before it runs a pretty good stitch. I have kindly started to remove it, tweak it with no results. I guess I have not bent it enough in any way and am still at max with the screw tightened on re-assembly thinking I may have some change, nope.

So with the need for some fine adjustment with whats been mentioned.  I am now getting around to order another, as this part may get all jacked up before I'm done bending it. And this may be a time to just bend another instead.

I thought this is a great time to just ask your opinions and for sure feel free.

Thanks

Floyd

[brmax]

As the photo shows the bobbin tensioner spring,  and is a pretty tough nut trying to carefully bend with a couple pair of pliers.

To think id like to be able to run a tensioned thread on the bottom, ? na

The knot most times is above center and would appreciate it if I could get it to just move when I adjust the screw.

 

Edited December 20, 2016 by brmax

[TinkerTailor]

Did you back out the lock screw before you adjusted the bobbin tension? That little round hole is where there is a setscrew that is supposed to lock the tension screw. If this is in too far the tension screw may contact it and not go in any further leading to too low max tension.  Also, If this screw is missing or not tight, the tension adjust screw may back itself off while sewing. This happened to me, somehow from asia to here that setscrew was absent. I would set the bobbin tension, and then try to match the top to it. As i tried, i would have to back the top off a little at a time until there was no top tension at all. No end of confusing tension issues until i got it installed. Rock solid ever since.

[brmax]

Thanks Tinker, on this one I do or did loosen the set screw when I started working with it. Just from picking up some procedures here listening a bit, and some of the different guys doing some u tube videos. Its all a great benefit for sure, even just reading some conversations without having a particular machine or doing a certain tooling technique. It seems later on many times some of the key things are remembered, hopefully more than forgotten

Back at it, I've  tried bending the spring steel a bit but as mentioned I was trying not to screw it up. Even considering that little piece is pretty darn tough, so one reason to mention it here. Also a good idea as more experienced members can throw some required and other questions, I totally get that as an old wrench it just works best.

With the situation here I have removed the spring screw and re-assembled and found the tab if one can call it that where the screw goes thru, well it does bottom out against the bobbin case itself, and so none or not enough squeeze for the thread. Maybe I should use this tensioner spring on for 346 and up possibly : )

In the past I have adjusted a bit with the top tensions in the beginning and seemed to have dialed the machine in with the bobbin spring as is, but from the get go noticed I could not get the bottom side to produce much tension to see and why I should want to get what everyone doesn't want.  I'm laughing trying to figure why I want that problem

Its crazy but it has a pretty decent stitch in my opinion just not available as it should be, so to bend the spring correctly maybe impossible.

I haven't called any the pro shops for parts yet, and considered that in the steps ahead respectfully. And thought its a pretty good time to ask here as some time is avail with the holidays.

Hey thanks, and good day there

Floyd

Edited December 20, 2016 by brmax

[Wizcrafts]

Floyd;

If you call Steve at Leather Machine Company, I suspect that he will send you a replacement bobbin tension spring. It's definitely worth a try.

[brmax]

Hi there Wiz, you know I think your right, I only talked to the shop once out there and it was a real good experience from the front desk clear back the machine techs.

Well, this was a part that I decided to take another crack at this evening. Not quite as familiar with the shuttle machines but I think the other shop tools scared it and so tapping around on tension spring a bit with some brass did the trick.  I guess a learning curve of sorts so anyway at present I can pull the knots down and believe theres a bit more working area to be had, or a couple turns possibly.

At first jackin around with it the center of the spring was preventing the bobbin assembly and so a tap or two adjustments remedied that to a better curve. I managed to run a test on couple 5oz layers and then again with a couple 8's and so with perseverance turned a pretty good test run this evening.

Now I can get cracking on some projects, and appreciate the tips you all.

good day

Floyd

 

[Darren Brosowski]

I see these questions a lot and there are a few issues.

1/ when setting the bottom tension it is pretty much a case of you just want to feel some resistance as you pull it through the feed dog. It is hard to quantify but you don't want it to come straight through and you don't want to put your foot against the machine to pull it out so about half way between those extremes.

2/ When setting the top tension the most important issue is that the thread goes around the main tension 1 1/2 times and the tension roller spins as you pull the thread through. Sometimes this means that there will be very little tension on the main spring. The tension at the top/back is the one that puts the pressure on the thread to spin the main tension.

There are many ways to balance the tensions and no two people will agree as with three springs there are a thousand ways to do it. Nobody is right or wrong and you need to find a way to balance everything that works for you

 

 

[TinkerTailor]

2 hours ago, Darren Brosowski said:

There are many ways to balance the tensions and no two people will agree as with three springs there are a thousand ways to do it. Nobody is right or wrong and you need to find a way to balance everything that works for you

This is so true. It is funny, when I was first figuring out this machine, both before and after i figured out the screw was missing. I must have tried 5 methods of setting and balancing tensions until I finally settled on a threading/tension configuration that works for what i am sewing. (Btw with that  bobbin screw missing, setting bottom tension was like weighing a bucket of water with a hole in it.....) It was not just about tension, but how the thread pull feels on this machine. I firmly believe that even withing supposedly identical clone machines, there are enough inconsistencies between them that the two machines may work best with differing setups.

Also, I have my thread tension quite tight. I tried to sew with the tension loose, and it sews beautifully in whatever i set it up to sew, but I ran into problems changing to other materials. I found that when I switched from sewing hard veg sammiches over to something like heavy canvas sewn to softer horween, the stitch would be too loose, or would not be even close to centered. I was constantly balancing it for the material at hand. I also had to spend 10 mins to get it right after a thread size change.  Then I tried with the tensions much higher, and i have found that i can switch thread size from 138-277 and mix up the materials without the balance issues. It seems to me that when the tension is light, the material composition effects the stitch formation and thread pull much more than if it is higher. These 441 machines are tanks. They were built to sew anything sewable and handle the tensions required for this. They do not have the finesse for low tensions in my opinion. To me, its kinda like an NFL runningback trying ballet.

I also installed a bicycle rear view mirror on the arm of my machine so i could see the stitch formation right behind the foot while sewing. I take it on and off, but it sure comes in handy sometimes, especially in difficult materials/problem areas. The additional sight line allows you to see if it skipped a stitch much easier and back up to fix it before its too late. Also helps prevent the wife sneaking up behind me and scaring me while i am sewing and making me drive crooked....

Edited December 21, 2016 by TinkerTailor