Singer 7-33 Stitching problem & parts

[hackish]

3 hours ago, Evo160K said:

The shuttle tension spring is not really rough but I feel like its related to the problem because it is limited on the amount of tension it can apply.  Hackish it looks like the spring has been bent down to try to create more tension on the thread.  If so, that may be because a groove has been worn into the shuttle underneath the spring?  I salvaged one of my shuttles by having a welder fill in that groove with a spot of weld......smoothed it down with a dremel tool....worked fine after that.

I'm not sure how much is necessary when sewing such thick material.  Aren't the needle and bobbin threads supposed to cross in the center of the goods, is that the case for the 7-33?

The shuttle is not worn. It's a 50 year old new part that was never used.

The threads are supposed to cross in the middle of the material but it's going to be a ratio between top and bottom tension. At this point I'm feeling like I should just return the machine to the seller and go buy a consew 7-33 or something like that instead.

[Constabulary]

You say the thread is resin coated. I have not worked with this type of thread but maybe it needs a certain lubrication. To eliminate a thread issue I´d try an uncoated polyester thread instead just to make sure that THIS spool of thread is not causing the issues. I know you have to use this thread because of certain specs but maybe you have just a spool of poor thread. Sewing machines sometime act different with certain threads.

F.I. I wanted to use a pure cotton threads on my DVSG / BUSMC #6 and by the lord it did not form a loop and I have no clue why. I tried different tensions and needles but no change. Then switched to a Polyester thread and it sews like a dream right away. I still want to use the cotton thread but cannot see where the problem is. Sounds stupid but thats how it is.

When your machine came from a dealer tell him to setup the machine for the material and thread you want to use.

Edited October 9, 2016 by Constabulary

[hackish]

5 hours ago, Constabulary said:

You say the thread is resin coated. I have not worked with this type of thread but maybe it needs a certain lubrication. To eliminate a thread issue I´d try an uncoated polyester thread instead just to make sure that THIS spool of thread is not causing the issues. I know you have to use this thread because of certain specs but maybe you have just a spool of poor thread. Sewing machines sometime act different with certain threads.

F.I. I wanted to use a pure cotton threads on my DVSG / BUSMC #6 and by the lord it did not form a loop and I have no clue why. I tried different tensions and needles but no change. Then switched to a Polyester thread and it sews like a dream right away. I still want to use the cotton thread but cannot see where the problem is. Sounds stupid but thats how it is.

When your machine came from a dealer tell him to setup the machine for the material and thread you want to use.

The thread is not the issue. I've tried 3 different cones of it and it's the identical brand and type the factory uses on the identical machine. I have fixed the skipped stitch issue, it's just the mystery loops forming on the top of the seam now.

 

[mikesc]

Any chance that you have a speck of dirt inside of the spring tensioner ( the barrel part that it sits in ) or even in the spring coil, that would make it stick just ever so slightly from time to time and give a "loop"..had that problem with a totaly different machine, was driving me nuts until I thought strip and clean it and maybe inspiration will come to me whilst I do that, there was the tiniest amount of dirt on a cotton bud when I cleaned it, put it back together and its sewed perfectly from then on..then again maybe I just let the gremlin out when I stripped it.

Edited October 9, 2016 by mikesc

[Singermania]

When these type of problems occur its a good idea to swap the thread for a completely different brand or type, replace the needle.   Some machines simply don't like some threads.   Also both of your top tension units are wound up tight, I'd back them right off and try again.   Overtight on top will drop stitches.

[hackish]

9 hours ago, mikesc said:

Any chance that you have a speck of dirt inside of the spring tensioner ( the barrel part that it sits in ) or even in the spring coil, that would make it stick just ever so slightly from time to time and give a "loop"..had that problem with a totaly different machine, was driving me nuts until I thought strip and clean it and maybe inspiration will come to me whilst I do that, there was the tiniest amount of dirt on a cotton bud when I cleaned it, put it back together and its sewed perfectly from then on..then again maybe I just let the gremlin out when I stripped it.

I've had the shuttle spring in and out probably 5 times so it is definitely clean. For the lower tension on the machine itself I can watch the tension pulley rotate with each stitch so there is nothing evident there. I've had every part of the machine I can think of apart several times. I may have reached my limit of frustration. I think I should buy a few parts I know need replacing and buy a Consew 733-5 or 733-25. The number of hours I've wasted on this machine I probably could have bought a new one anyway.

[Singermania]

You also have a lot of white crap coming off the thread... starting right at the top (secondary) tension unit, if that is normal for this kind of thread then 'ok', but if not it indicates to me the top thread is under considerable strain.  I have eight or so 7 class Singers and a few even bigger Adler, but don't recall any of them doing that.  With regards to rotation off the bobbin, I find it can go either way and is not critical.   Lastly you are sewing tight weave webbing, this stuff sticks to or closes up around the long left groove in the needle not allowing the thread to hide in there...(yes technical speak), try going up a needle size to increase the size of that groove.

Look forward to hearing your results.

[hackish]

28 minutes ago, Singermania said:

When these type of problems occur its a good idea to swap the thread for a completely different brand or type, replace the needle.   Some machines simply don't like some threads.   Also both of your top tension units are wound up tight, I'd back them right off and try again.   Overtight on top will drop stitches.

I have coates, american eford and a DJA (made in the USA) branded thread. The factories are primarily using coates. I will try backing everything off again. The frustrating thing is that I can't tolerate a single messed up stitch. Since a harness is a life saving device you can't just rip out a faulty seam and do it over a bunch of times. Lots of $$$ and time in the trash if the machine messes up.

[hackish]

6 minutes ago, Singermania said:

You also have a lot of white crap coming off the thread... starting right at the top (secondary) tension unit, if that is normal for this kind of thread then 'ok', but if not it indicates to me the top thread is under considerable strain.  I have eight or so 7 class Singers and a few even bigger Adler, but don't recall any of them doing that.  With regards to rotation off the bobbin, I find it can go either way and is not critical.   Lastly you are sewing tight weave webbing, this stuff sticks to or closes up around the long left groove in the needle not allowing the thread to hide in there...(yes technical speak), try going up a needle size to increase the size of that groove.

Look forward to hearing your results.

I think the thread is under a lot of strain at this point. I've been starting with the bobbin loose as hell and then cranking the top tensions up every pass to see if it is getting better or worse. I'll then add a bit to the bottom and repeat the process.

[Singermania]

Yes I understand what you mean about getting it right, with leatherwork there can be no compromise !!