A tale of a broken screw, loose screws and a DIY mechanic for the Singer Hemstitcher 72w-19

This lovely 72w19 Singer Hemstitcher (circa 1945) has caused me all kinds of grief this month.


I have had a persistent problem with this machine every since I purchased it 4 years ago. The left needle thread has a tendency to break, almost randomly. I can stitch some distance, it will start skipping and then get cut by either the needles or the piercer. I have played around with various settings and adjustments continuously over all this time. Sometimes I can improve it, other times it becomes worse. Despite all these adjustments, the right needle continues to behave as it should and the left will not.

One day, I noticed that the piercer holder was loose. I could wiggle it with my finger. This led to me over tightening the piercer holder screw and breaking it. This screw is a size #6 and some of the screw was stuck in the machine. How to get it out?



It would be easy to say I am not a sewing machine mechanic. I have done some basic tuning up on regular sewing machines. Set the timing on both of my sewing machines. Cleaned, oiled, lubed. But that is about it. Armed with my 72w19 manual, I set out to fix my machine, extract that screw and get to the bottom of the thread breakage problem. The engineers who designed this machine and most mechanics who worked on these are all gone now. Those that are left are hobbyists, for the most part. Some are very good, but too far away to consult. Other mechanics rarely work on or understand these machines.

Even with the manual, there are gaps of knowledge. Perhaps later I will post a little about the history of these machines. One thing I did learn is that the ladies who purchased these machines attended a training and certification class so they could adjust them on their own. I am sure they picked up all kinds of information never written in the manual.

So back to the broken screw. Nothing could happen until that screw was extracted and replaced (and luckily I did find a replacement).

Assemble some basic tools:
1. Drill (variable speed, set on slowest setting)
2. Very small metal cutting drill bits (like 5/64")
3. Punch
4. Extractors and/or left hand drill bits
5. A steady hand.

Step 1
Use an auto centering punch to punch a pilot hole into the broken screw. There are different sizes and shapes of punches. I found one that is about the size of an ink pen. You press down on it and an internal spring forces the punch. A very nifty and useful gadget for small spaces (also expensive uni-tasker). You may need to do several punches because the surface of the broken screw will probably be uneven. This punch is critical so that the drill with a metal cutting bit doesn't float around.

Step 2
Using the drill with the regular metal cutting bit, drill a hole in the center of the broken screw. Make sure the drill is on a slow speed setting. In my case, I could drill all the way through the center of the screw to the other side and not risk damaging other components. Even so, drill just far enough to be able insert a slightly larger extractor or left hand drill bit. Stop every so often to clean out the hole and to let the drill bit cool off. The drill bit may dull quickly, so be prepared to replace it.

Step 3
If the screw is not jammed too tightly into the machine, you may be able to insert the extractor and turn the screw out by hand. This is what I ended up doing in my case. If you need more power, use the drill but be sure to reverse the direction of the drill.

And here is the result. You can see how small that broken screw bit was and why I was so nervous about it.

With the broken screw removed and a new one inserted, I once again began to check all the possible adjustments. In this I discovered more lose screws. There were lose screws on the piercer bar, and underneath the bobbin. Cleaned more lint and gunk out of areas I rarely clean. Oiled every moving part. Adjusted the vibration (zig-zag), pitmans, levers, etc. I could definitely say I have learned a lot by over adjusting some part and seeing what would happen (very carefully of course). I think I may have zeroed in on the vibration setting as the sources of the skipping as the left needle only skips on the inside vibration.

And then the piercer snapped in half the other day. I can't figure out how or why. Did I have it set too low in the machine? Maybe it was just worn out and over abused?

Thankfully, replacement piercers can still be found. Though they are very expensive. I bought two, just in case this happens again. Hopefully not.

The Singer Hemstitcher 72w-19 broke down

Every time I sit down to stitch blankets on the hemstitcher, I cave and try to adjust it. The left needle thread continues to break despite everything I have done. One commenter suggested I move the main piercer either up/down or left/right. While I attempted to do this, I discovered that the main piercer holder was loose. Is it possible that the main piercer holder was vibrating or moving as a stitch is formed? It could explain why I could stitch a few inches and then the left thread would break randomly. The holder was only marginally lose but I could moved it ever so slightly with my finger.

So I attempted to tighten the screw on the holder. I wrenched down on the screw and shouldn't have done that. After all it is a 70 year old screw. And yes, the screw broke.

There is a broken part of the screw stuck in the machine. Thankfully, I was able to locate a new screw. One nice thing about the old Singers is that the engineers used as many of the same parts in multiple machines as they could, especially screws. The problem, of course, is extracting the screw. I zoomed in pretty close in the picture above, but that screw opening is only about 1/8 inch. I am very nervous about doing this because I have to be very, very careful to not damage the threads of the piercer holder. That part will be very difficult and expensive to find, if at all. I probably will buy a Dremel as I don't trust myself with my regular drill. I don't know.

I am my own mechanic when it comes to repairing my Singer Hemstitcher 72w-19. There are very few mechanics familiar enough with this machine that I would trust them to work on it. I have really spent a lot of time studying it and I think I now understand how all the important parts work. The movement of the piercer thread holder as it stitches proves that it can break or cut the threads. It moves much more now that the screw is not completely there.

And of course this happened at a time when I have two large blanket orders. Thankfully, my customers are willing to wait. But if I can't fix it, then I will be taking these blankets to one of my competitors to finish. I am a bit stressed about the whole thing.

Troubleshooting a stitching problem on a Singer Hemstitcher 72w-19

I have previously blogged about my hemstitcher and how temperamental it can be. I would blame most of its stitching problems on its "personality" and just try to deal with it. The primary problem I have experienced is skipped stitches. Skipped stitches are very bad because that extra thread can get caught around or under the piercers where they are cut. Usually, I would experience skipped stitches with either the left needle or the right needle, and occasionally both.

In the past, I would work through the most "obvious" and possible solutions to prevent skipped stitches. Most how-to guides suggest rotating the needles out ever so slightly. I would thoroughly clean, oil, and lube. I would check the threading. I would replace and reset the needles. Often, I could solve the problem enough that I would experience little thread breakage. That was until I worked on a blanket order that consisted of flannel fabric that came from H - E - double hockey-sticks L. If you heard a scream, followed by head banging 2 weeks ago, it might have been me.




The picture on the left shows the stitching along the long grain (the grain parallel to the selvedge edge, also called the warp). You can see the frequent skipped stitches. In fact it skipped so often that I was experiencing thread breaking and thread fraying every 2 inches of stitching. The picture on the right shows the stitching along the cross grain or weft. The stitching would be absolutely perfect - no skips or thread breakage.

My initial thought was there was something wrong with the fabric. It either was a blend or had too much sizing. My hemstitcher will not stitch reliably on polyester fabric blends, but a burn test confirmed it was cotton. I couldn't wash the blanket to rid it of the sizing. Some flannels do not look the greatest after washing, and usually the sizing does help with the stitching. Too much sizing is an indication that the fabric is of lesser quality, although not always. This order was a 45" x 45" blanket consisting of a panel print on the front and a coordinating print on the back. I had very little scrap left over to do any testing to see if it was indeed the fabric. Stitching on other softer flannels was easier, although I was still getting thread breakage.

It took me a while to finally figure out what the problem was. One significant clue is the stitching difference between the long and cross grains. There are distinct properties to these two grains that affect how fabric behaves and also how it behaves as it is stitched. The long grain (warp) consists of yarn that is pulled taut. The cross grain (weft) consists of yarn that interlaces with the long grain. It goes over and under the long grain yarns. If you fray out fabric, you will notice that the cross grain yarn has a wave and the long grain is straight. You can pull the cross grain yarn like a spring, but the long grain will snap. Because of this, the cross grain of a plain weave fabric has a natural, built in stretch.

While stitching, a hemstitcher inserts two needles into a pierced hole. As the needles come up, they swing out pulling the yarns of the fabric apart. The next stitch will hold the hole open. Each hole requires three stitches. The machine has to work harder along the long grain of the fabric because of the inherent nature of that grain. The machine works less hard on the cross grain because of the natural stretch built in.

Ok. So now I knew the problem, but I didn't know how to solve the problem. I have to stitch around all four sides of my blankets, so there had to be a way to adjust the machine so I could stitch and not get anymore skipped stitches. I pulled out my usual help guide in diagnosing stitching problems. The Coats & Clark pamphlet titled The Basics of Hand & Machine Sewing, published in 1995. This is a fantastic pamphlet that covers many aspects of needles, thread, proper tension, etc. I don't know if this is available anymore, as I acquired the full set of Coat & Clark pamphlets in college. The best part of this particular pamphlet is a Checklist in Case of Trouble. Every possible stitching scenario is covered.

At the top of the list for skipped stitches was Wrong size or type of needle for the fabric. But I skipped that because I assumed I had the right type and size of needle. Other solutions suggested:

Timing of machine - check
Lint - check
Threading - check
Damaged needle - check
Sewing at a steady, even pace - check
Fabric with excess finish - ? possibly
Hold fabric taut while sewing - check

Nothing seemed to make a difference. I think the excess fabric finish contributed to the problem, but was not the root cause. Stitching on other fabrics showed the problem still existed. So I finally decided to cave and try the next needle size up. It couldn't be that simple, but why not try.

In a true, head smacking moment, the machine stitched absolutely perfect on both grains. And it makes sense too. A larger size needle is stronger and can pull the yarns of the fabric apart easier. Since I have to stitch through two layers of flannel, a larger size needle is necessary. Now I have to decide what to do with 100 size 12 130x3 needles, while I wait for an order of size 14 needles.

One thing I am not sure about. I had some Singer brand size 14, 130x3's laying around loose in the table drawer, which work great. The Singer brands are known to be the best, but also the most expensive. I am ordering the Organ brand (which is what my size 12's are) in the size 14. Hopefully, there isn't too much of a quality difference.