Singer 7-33 Stitching problem & parts

[hackish]

I tried more and less pressure on the foot. No difference. I re-adjusted everything including the hook. This time I dropped the needle bar so the eye of the needle is far below the 1/32" the manual says - more like 1/8" below the hook tip. It's not dropping stitches anymore but the loops forming on the top are more pronounced now. It seems to me that it could be related to bottom tension but it's like a loop of loose thread is forming on the bottom and then is being pulled through the material by a "kink" in the thread as the needle rises.

 

I need a transparent sewing machine so I can see what's happening while it sews!

[Yetibelle]

Here are my .0002 cents. 

First that stich-per-inch looks a little tight for Size 27 needle and 346 thread.  See if you can max out the stich-per-inch (I think it is like 5) then try it.  Also sometimes the needle gets a little bent, you can't see it with the eye, so swap out the needle for a new one.  If that does not help....then.  Try a smaller needle like a 22- maybe some smaller thread like 277 and 207?  Try the 277 on top and the 207 on the bottom again with the longer stich.  Then test that out on the lighter material and see if that stops the skipping.  I typically find skipping is a bad needle, or your pulling or pushing the material and the needle ever so slightly misses the hook. 

Also send over a pic of how your threading the top town, and the head of the machine. 

Its not that far off

[hackish]

The harness that I'm sewing specifies that many SPI as well as the thread and needle type. These machines are industry standard as is the needle size. It has to be sewn to spec. I've tried changing the needle.

 

You can more or less see the thread path. The thread goes all the way around the lower tension disc before exiting through the spring.

[Yetibelle]

Yeah nothing looks obvious from that, looks like a great machine.  I understand the specs your trying to get.  I was just wondering if going slightly smaller made and difference?  Could be a loose screw on the feed dogs assembly, causing some play left or right?  I had that, when I used a bolt down there that was not standard it didn't pull right untill I had it all correctly tighten down.  

 

[hackish]

There is a good amount of right/left play in the feed dogs but I haven't figured out how to tighten it. The shaft is in there firmly but I think the only way to tighten up the feed is to shim it since the assembly that holds it is cast. Although not ideal, I'm not feeling like that is the issue because I can feed it smoothly. It has to be something in the tension. Any suggestions on how much tension to use for the bottom?

[Evo160K]

50 minutes ago, hackish said:

There is a good amount of right/left play in the feed dogs but I haven't figured out how to tighten it. The shaft is in there firmly but I think the only way to tighten up the feed is to shim it since the assembly that holds it is cast. Although not ideal, I'm not feeling like that is the issue because I can feed it smoothly. It has to be something in the tension. Any suggestions on how much tension to use for the bottom?

Coincidently my 45K53 had the same problem recently with the feed dog screw, it wouldn't tighten down enough on the feed dog, letting it drop.   The mechanic who's helping me restore the machine put a small, copper shim in behind the feed dog screw, the copper, of course, crushed and held the dog and screw tight.  He said there were singers that he maintained for his employer that used small, serrated, copper washers; I don't remember if he mentioned where they were used. Others may know.

Hackish, does the shuttle cylinder tension spring in the picture above look a bit rough or distorted?  If so, could it be snagging the needle thread occasionally as it comes around creating an issue or perhaps interfering with the bobbin thread in some way?

Edited October 8, 2016 by Evo160K

[Constabulary]

How it the thread coming off the thread spool? Is it a X-wound cone of straight wound spool? Sometime thread keeps hanging when the thread is not coming off the spool properly . The thread guide arm of the thread stand should be straight above the spool. I´d also leave out the wax pot when you do not sew with waxed / oiled thread. At least worth giving it a try.

[TinkerTailor]

Is the thread snapped into the second tensioner? It looks like it may be riding around the outside. Give it a firm tug and make sure it is all the way between the discs.

Second, the thread  looks a little tighter coming out of the thread lube pot than it is going in, its it catching up in there? What happens if you sew without the lube pot in the path, does it still act up?

[hackish]

6 hours ago, TinkerTailor said:

Is the thread snapped into the second tensioner? It looks like it may be riding around the outside. Give it a firm tug and make sure it is all the way between the discs.

Second, the thread  looks a little tighter coming out of the thread lube pot than it is going in, its it catching up in there? What happens if you sew without the lube pot in the path, does it still act up?

Don't quite understand what you mean about the second tensioner. It's wrapped all the way around the tension disc to make sure it doesn't slip. The manual was printed in 1918. That was before nylon was invented so I expect old cotton thread only needed a single loop.

The lube pot does add some tension to it but it's consistent. I expect that would be at most a tiny change while the problems I'm having are not tweaks to stitch quality, they're major problems. The thread is coated (resin perhaps) and that's what the white flaky stuff is - I could omit the pot.

18 hours ago, Evo160K said:

Coincidently my 45K53 had the same problem recently with the feed dog screw, it wouldn't tighten down enough on the feed dog, letting it drop.   The mechanic who's helping me restore the machine put a small, copper shim in behind the feed dog screw, the copper, of course, crushed and held the dog and screw tight.  He said there were singers that he maintained for his employer that used small, serrated, copper washers; I don't remember if he mentioned where they were used. Others may know.

Hackish, does the shuttle cylinder tension spring in the picture above look a bit rough or distorted?  If so, could it be snagging the needle thread occasionally as it comes around creating an issue or perhaps interfering with the bobbin thread in some way?

I can try shimming it. It would be nice to eliminate slop, but the feed dogs fit so well in the needle plate that the slop is only there when I've taken the plate off.

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. I'm not sure how much is necessary when sewing such thick material. I might spend a few more hours this evening to see if I can make any headway.

[Evo160K]

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?