Skipping stitches on 29K70 and Needles, Needles, Needles...

[Snakeoil]

Yesterday, a friend dropped off some nylon straps for me to sew into custom length straps for a large structure he will be loading in and out of his Sprinter van. My 29K70 was giving me fits with skipped stitches and as bad as sewing several inches with not a single stitch. I adjusted the timing multiple times and  with time and patience, managed to make the 4 straps for him. But my wife told me that she was sure that a fist fight was about to break out in the basement, even though she knew I was down there alone. Yes, I was doing a Basil Fawlty impression as I berated my machine. Although I did refrain from giving it a proper thrashing.

Today, having cooled off, I did a little research. First, I read both of the original manuals I have and they both say exactly the same thing. Missed stitches are probably a needle problem. I went to Google for more and found a pretty good write-up that walks one thru the missed stitch issue and ended up at the same conclusion, bad or wrong needle.

So, I went back down into the basement, where my machine cowered in the corner, donned my jewelers visor (magnifies up to 10x) and started looking at needles. I also looked at the needle and thread charts that I've found or was directed to here by members for proper needle to thread sizing.

A slight tangent first. When I got my machine a few months ago, the little drawer in the base was packed with needles in cases and loose in the drawer. I figured that I had a lifetime supply of needles. I did my research and learned about needle sizes and then on a bitter cold day, hunkered down in the basement and went thru what could easily be called a pile of needles. I had original SIMANCO needles and other brands. I had plastic caddies with brand new GB needle in several sizes. I had needles that looks like something you could use to frame a house. I sorted them, put them into little vials with nicely printed labels with sizes and was quite pleased with myself. I had what I thought was a lifetime supply of needles, given the hobby application for this machine.

Meanwhile, back at the ranch, something I noticed in the two singer manuals was the differentiation between cloth needles and leather needles. For this machine cloth requires 29x3 and leather 29x4. All the cases, caddies, envelopes in that little drawer said 29x3, regardless of the size. So, it would at first glance appear that I have zero leather needles. And I got this patcher from a shoe repair shop that was closing up.

I put on my jeweler's visor and started looking more closely at my needles. The older ones with no packaging were interesting. It appears that they had been re-sharpened. The point was not symmetrical and was more of two flats that came to a point, and at a rotational angle relative to the eye. I looked at brand new GB needles and they looked nothing like that. So, my plethora of needles is really more of a pile of scrap metal.

I put a new needle into the machine with a properly matching thread size and sewed a perfect seam down a piece of that same nylon strapping I was sewing yesterday. My guess is the thread I was using yesterday, a V92, was a tad too big for the 130 needle I was using. Although the chart  have says a 130 will work, I suspect that a 140 would have worked better. What I was finding as I worked on the straps yesterday was if I went slow and ran the hand wheel by hand, all was well. But if I upped the speed with the treadle, I'd start to skip stitches. I suspect that the slipperiness of the nylon strapping did not help produce a decent loop for the shuttle to catch.

I did measure all my thread today with a micrometer and compared it to the chart that Wiz directed me to (thanks again, Wiz). Turns out I have 1 spool of V46, several of V69 and 1 of V92. It was the V92 and a new 130 needle that was giving me agita yesterday. I never would have guessed that needle size would create this problem. Just proves that because you can sew, does not mean you fully understand how a machine sews.

This reminds me of working on friend's cars as a kid. I was always a motorhead. I'd get calls for dead cars and the owner would have all kinds of theories on why it would not run. More than once I turned on the ignition and saw that the car was out of gas. Yesterday, my 29K70 was out of gas.

regards,

Rob

[Bert51]

When I first started sewing, I to had problems with missing stitches and like you I worked out just because the thread fits through the needle, does not mean it will sew smoothly.

I found on this forum where some one put up a post about getting a meter of the thread you what to use and if the thread slides down when held on an angle it's okay to use, if it sticks, go up one size.

Also known as the school of hard knocks.

Bert.

[Wizcrafts]

Okay. I use #92 thread in my long arm, big bobbin patcher and #69 in the small bobbin 29k71. I have round, lr and diamond/tri point needles in every size. When sewing leather I use a leather point needle of some configuration. Most of the titanium needles I now buy are tri-point. They let the thread lay on top more than the slicing point needles do. But, you weren't sewing leather...

Webbing is a woven synthetic fiber material. Leather point needles will slice and break the strands in the woven webbing. They are the wrong point. You should use 29x3 or 135x17 round points when sewing woven and cloth materials.

Size-wise I use a #19 or #20 needle with #92 (T90) bonded thread. If you are using a #22, the eye is way to large. There won't be any resistance in the eye as the needle makes its down/up/down jog and the loop may dissolve before hook time occurs. You can counter this by playing with the settings of the barrel adjuster vs the top flat spring on the arm. When I encounter difficult materials that cause skipped stitches I try loosening the flat spring and cranking up the lift from the barrel adjuster. This is in addition to checking and tweaking the hook timing.

If you have adjusted the timing perfectly and tweaked the take up adjusters and are still getting skipped stitches, replace the paddle shaped spring inside the needle bar.

[Constabulary]

Patchers - they can be a lot of fun but even more a pain - sometimes.

3 hours ago, Wizcrafts said:

If you have adjusted the timing perfectly and tweaked the take up adjusters and are still getting skipped stitches, replace the paddle shaped spring inside the needle bar. 

Ouuuuh yes, this little annoying thingy can be a pain and is the last thing you would think of.

Not sure if it is mentioned in the manual but you can also move the needle holder a bit sideways (by loosening the upper screw) when the hook will not grab the thread. As Wiz said - you can also use 135x17 (or 135x16 for leather) they have the same length as the 29 needles but have a scarf above the needle eye. I´m using 135x16 / 135x17 needle only in my 29K71.

[Snakeoil]

I guess it is all part of the right of passage. When any type of machinery is new to me, there is always some suspicion that something is going on that I'm not aware of. I don't have a lot of feel for what is acceptable wear which put that in the back of my mind all the time.

I now suspect that those needles that look like they had been re-sharpened, could be what Wiz called "diamond point. I need to learn a bit more about needles. I was on a site several weeks back for a company that manufactured needles. I think it was GB. The range of styles and sizes was truly mind boggling. I also read a post here where someone was having trouble and a member mentioned a different type of needle with a larger scarf.

I had that paddle spring off the needle bar when I had the head apart. The spring is fine. But there was a track cut into the needle bar from the thread passing by. Someone else who was rebuilding a 29K machine mentioned this issue and was not sure if that track is supposed to be there or is simply wear. I suggested a fix using epoxy if indeed it was wear. I chose not to fix mine and if that track is wear, it could be contributing to the problem. Although, I would think that the creation of the loop is a job for the needle and the material being sewn. But that could be ignorance talking on my part. I need to watch the machine go thru the entire cycle to get a mental image of all the parts moving and which moves when and how they interrelate.

I read in a post here when I first got the machine that sewing a straight line with them is difficult at best. I was skeptical of that comment. But since then I've learned that it is pretty damn accurate.

I appreciate the input, guys.

regards,

Rob

[Wizcrafts]

2 hours ago, Snakeoil said:

I chose not to fix mine and if that track is wear, it could be contributing to the problem. Although, I would think that the creation of the loop is a job for the needle and the material being sewn.

The loop is created when the needle makes its down/up/halt jog. But, the take-up spring exerts pressure on the take-up lever at this point. If the little paddle spring and the area behind it are badly worn the spring pressure will cause the loop to dissolve before the hook can pick it off.

The original System 29x needles have no scarf above the eye. The current System 135x16 and 17 have a scarf. You can move the needle clamp to the right to get it closer to the hook than you can with a straight  29x3 or x4 needle.

[CowboyBob]

 

3 hours ago, Snakeoil said:

cut into the needle bar from the thread passing by. Someone else who was rebuilding a 29K machine mentioned this issue and was not sure if that track is supposed to be there or is simply wear. I suggested a fix using epoxy if indeed it was wear. I chose not to fix mine and if that track is wear, it could be contributing to the problem. Although, I would think that the creation of the loop is a job for the needle and the material being sewn

Epoxy would wear quickly,we always filed them & yes if this is deep enough it is one of the many reasons it could be skipping.

Edited March 3, 2020 by CowboyBob

[Snakeoil]

Thanks guys.  I truly appreciate the follow-up info.

There are epoxies with metal filler or I can add metal powder to JB weld to give it better abrasion resistance. Another option would be to braze it and then file it down to original specs. Keep in mind that this is purely a hobby machine for me. So, it will not see a lot of wear. They also make super glues with metal fillers in them now. My cousin has used them to repair damage to engine blocks and similar. They work great. But I realize that those repairs do not see any abrasion. And nylon thread is like running lapping compound thru the area.

I have the needle as close to the shuttle hook as I can get it.

I just have this thing about keeping original parts working. There was a bobbin in the drawer that looked like it had been thru both world wars. The hole in the hollow spindle was ripped, the flange on the non-slotted side looked more like a Chinese coolie hat. I made a jig and brought it back to shape, fixed the hole in the spindle and had to take a few thousandth off the OD because it had stretched a bit as I reformed it. But it's back in action now.

I suppose I could just spring for a new needle bar. But that would just go against my grain. ;-)

regards,

Rob

[mikesc]

Another option would be to braze it and then file it down to original specs

Use Nickel rod ? ..harder..resist abrasion better ..a little more of a challenge to do, but :)

[shoepatcher]

JB weld better to use and fix groves.  Depending how deep the grove is, I sometime file the steel down just a little  where the thread has cut a grove in the needle bar at the spring.

Glenn

[Dufresne]

What do you clean the needle bar with before applying JB weld? I have to fix a couple. Not sure how deep of wear is to deep. It makes sense to fix it while the head is apart.

[jimi]

I don´t think Brazing would be a good idea? The heat could bend the needle bar?? and there is a small channel for the thread to pass which has a small wall where the groove is closed with a thin strip of metal, that could come loose maybe??

[Snakeoil]

I'd have to look more closely at the needle bar to see what you are talking about Jimi.

I'll give JB Weld a try. I can always do it over with braze.

Cleaning should be done with acetone or lacquer thinner. You need to cut the grease/oil and alcohol will not do that. Mineral spirits will work, but can leave a residue behind. If you use min spirits, and this would work with zero solvents used, wash the bar with Dawn dish detergent and very hot water. Make the JB Weld fix and then once cured, oil the bar inside and out. The small amount of flash rust you will get between washing/drying and oiling will be of little consequence.

regards,

Rob

[Constabulary]

I know JB weld very well but I would not use epoxy on such a small "blemish". Not sure if it really would "stick" in place for a long time or how fast it will wear off again. How deep is it 0.2 mm? File it down - done. Really not a big deal.

[Snakeoil]

Slightly of topic, but let me tell you about using epoxies for stuff like this. I have repaired pitted front fork tubes for vintage British bike when replacements were not available. The bikes are still leak free. My cousin has an ancient Caterpillar dozer. The two hydraulic rams for the front blade were severely pitted. New cylinders were going to cost more than that relic of a dozer was worth. We fixed them with epoxy and that was probably 25 years ago and they are still leak free.

The front sights on Colt Govt model .45ACP pistols are staked in place. The slide recoiling tends to make them loosen over time. I install them with JB Weld and have never had one loosen after 1000's of rounds.

If you prep the surface correctly, the epoxy will stay put.

[Snakeoil]

Okay, I was fresh out of important things to do and thought I'd play with the needle arm. Pulled the needle arm out and took a closer look at the thread erosion. Here is what I found.

This is the needle arm surface under the little thread tension spring.

What I had not noticed before or simply forgot about (damn gray hair) was the wear on the thread tension spring.

So the combination of the wear on these two mating parts may have contributed to my skipped stitch issue.

I decided to use JB Weld on the needle arm wear. Here is the repaired (filled) wear area on the needle arm.

I did not fill the wear in the spring as being hardened and polished, I did not expect it to stick. So, I stoned the surface a bit and then polished on the buffing wheel with a little white jeweler's rouge. The wear is not gone, but greatly reduced. I think I need to put on of these on my list of parts I need to get.

So we'll see how the epoxy holds up. When I get around to ordering a few parts and they arrive, hopefully, I've have used the machine a bit and can see if the thread gnawed thru the JB Weld.

As a side note, I think my 9 year old laptop is dying. I need to get a new laptop and should it die before I do, please excuse any lack of response in the interim. I have my phone so it probably will not happen. But just in case...

regards,

Rob

[Constabulary]

As I said, I know JB weld very well and I´m using it A LOT (just as you do) - but keep in mind that you are threading the needle bar with a metal wire and the edges of the threading wire will wear off the epoxy sooner or later because it is "rubbing" exactly where the thread is running. So the groves in spring and needle bar are the result of the thread but also a result of the rubbing threading wire. I don´t think this tiny amount of epoxy will last for a long time. Just my 2 cents.

[Snakeoil]

Great point. I had completely forgotten about the threading wire. Yes, I can see that chewing thru the epoxy. On my wire, shortly after getting the machine, I did not like how that wire felt as it passed down and out the end of the needle bar. The wire, which is a high carbon steel, was certainly "biting" into surfaces on its way down the needle bar. So, I stoned the end and then polished it. Made quite a difference to how the wire travels down and out the end of the needle bar. So, although your point is well taken, my particular wire might not be as damaging as say a new one.

It's an experiment for sure. We'll see what happens. Appreciate the insight. A bit embarrassed that the effect of the wire never occurred to me. 

Homer Simpson moment for sure.