From The Bench

Plastic Gears or Metal?

Servicing sewing machines at my workbench since 1977 has given me very good insight to the many different designs used by todays manufacturers. The one concern I hear more on the sales floor than any other, is if our Husqvarna Vikings have metal gears or plastic? I proudly say plastic, of course they are a very high grade material with a much fancier name but I love to see the reaction it gets from the customer. Today all manufacturers use a plastic composite of some sort for their gears.. If a dealer says his are all metal ask him to take the covers off of the machine and look for yourself. It really isn't a bad thing that they are not all metal. Gear breakage in sewing machines mostly occured in a couple lines that Singer made back in the 60's and 70's. Because they sold millions of these machines, when the problems started many people heard about it. (Most manufacturers used plastic in their gearing even then). At that time we sold Necchi and Elna Sewing Machines. In fact, my father was the top Necchi Dealer in the country in 1957! Back then both Necchi and Elna used a high grade plastic material for their gears, bobbin cases, pulleys, cam stacks and even linkage. I am proud to say many today still operate with their original parts.

O.K,. then why the breakage with Singer? It was mostly due to the design of the gear not the material. When a sewing machine is running at a decent speed and something makes it lock up in an instant, all that force has to go somewhere. For Singer it tested the strength of their "bevel cut" gear. That particular type uses rather large tooth placement. When the machine is running only a few teeth of the gear are engaged with one another. After many years of thread jams and so forth, they would crack. I have been told that the early material used also required lubrication. Few people would regularly oil them so they got dry and brittle and cracked. Of course bad news travels fast so when friends asked friends which machine to buy, few said Singer if they had a Singer which broke a gear. Todays gears are made with more of a spiral tooth and more of the teeth are in contact with one another making for a stronger union between the gears. They also now require no application of grease by the consumer.

One very prominent brand on the market today uses a belt to drive the thread hook instead of gears. The thread hook is the spinning mechanism around the bobbin. It's function is to grab the loop of thread from the needle and tie the knot. I don't like that design myself because when lint packs in between the belt teeth and the pulley teeth the belt skips a tooth. Now the sewing machine won't sew and needs to be retimed and serviced. (At this writing the brand I am speaking of doesn't even have a cover over the belt to prevent lint from packing around it!)

To be fair to Singer, many didn't start breaking gears until the sewing machine was over 10 years old! Singer of course changed their gearing many years ago and the problem immediately stopped. Their gears today are as high quality as any other manufacturer and have no problem with breakage.

I have replaced many gears in many brands over the years and although its rare, yes even a Viking! Here is a challenge for you: Find another appliance in your home that will last as long as a sewing machine! I would say the average life of todays good sewing machines is still over 20 years of life. You may buy an upgrade sooner than that but if you don't you're going to have it for many years, especially if its a Husqvarna Viking!

During a presentation of the Husqvarna Viking Designer 1 one gentleman said to me, "For $6000 it better not require service". I looked at him and replied, "Even Mercedes has a service department." I guess he liked my reply, his wife now owns a Designer 1.