My sewing machine has a timing belt issue

Hello. I'm new here, but I was thinking of getting a new sewing machine to mend clothes, make adjustments in sizes and make new things from scraps of fabrics, when I remembered my dad has a sewing machine which he has had since the 70s. The only problem is that when I tried to use it I realised there was an issue with the timing belt. I'm wondering how to repair it, or whether it's worth finding somewhere that would repair it for me. The instructions I've read seem very complicated. Does anyone know if it is a big job or if I can do it myself?

I would expect the older sewing machine to be well constructed and well worth saving. Often a good cleaning is all that is necessary to get them working properly again, and maybe replace a rotted belt. Oils can polymerize and collect dust so become sticky instead of lubricating.

Having just adjusted the timing of a sewing machine… it's possible.
But if you are not into mechanics (and don't intend to do get into them), its probably best done by someone else.

If you can find the technical manual for the machine, the chances are better.

Thank you both... There's definitely something wrong with the timing belt. I cleaned and re-oiled it before I tried using it. I doubt I'll find the technical manual.  I think that's probably still in Rotherham (I'm in London, England). I'll and find someone in my area to get it fixed. I think there may be one person but I'll have to call and ask if they do repairs. Thanks for the advice.

What model sewing machine, I do not recall older ones with a timing belt.  

If it's a rotary bobbin machine it's probably worth saving.  If it's an oscillating bobbin machine then it is probably not worth saving.

you mean rotary hook, how made it?

Yes, it's the hook assembly that actually rotates or oscillates not the bobbin itself but that is always how I've always had the two most common types referred to as.

My point was that the rotary type are usually much better machines that last and last and last and are also capable of sewing much thicker materials without the bobbin jambing up.  We're as the oscillating type tend to much less heavy duty machines that don't actually stand the test of time (So called and so marketed "heavy duty" oscillating machines particularly drive me nuts, I've seen so called industrial machines sold and marketed for sewing heavy canvas for boat sails of the oscillating type wear out after only a few years of off and on use.  Where as old home duty only rated rotary machines last for decades sewing multiple layers of heavy canvas, jeans, hemp, and heavy ballistic grades 550d to 1050d nylon and poly fabrics.)

Now there are a few machines out there that are of neither the rotary or oscillating type.  Hook chain stitch machines that don't use any bobbins either single or double hook - those are nearly bullet proof so long as the hooks are still in good condition and/or replacements are available.  But I really don't trust the loop chain stitch compared to the lock stitch for most applications.  Then I've heard rumors and seen pictures of machines using a "shuttle" unit rather then a bobbin but never seen or played with one myself.  I believe that those would have much more value as a collectors item and you probably wouldn't want to actually use one of them.

That is why I say if it's a rotary bobbin machine then it's probably worth saving and if it's an oscillator then it probably isn't worth saving.  There are exceptions on both sides of that equation but they are exceptions not the rule.

If it's a rotary machine look for timing marks on the geared pulleys, it might just be out of time and/or need just a new belt (installed in proper time of course).

  Hi, I found an old singer machine that is gear driven and is light years above the belt driven dressmaker I had. The singer can go through layers of sailcloth and canvas. It is old from around 1970 or so . Keep an eye out for the older ones, they are much better than any newer ones.

From the way sewing machines work, I would expect that the timing belt  is in the column.  See of there is a cover that you can open.

You can also remove the plates around the needle foot to see what's happening below.  If the foot is removable, take that off too.

 basic idea.

https://www.youtube.com/watch?v=lT98wbDLVco shows a real machine and explains where the hook should be relative to the needle path.

Normally the action will work something like this:

Needle comes down, and punches through the fabric,

Needle starts up.  Depending on the cams internally, it may pause briefly.  As it comes up a bow is formed on the tail thread. (one furthest from the spool)  

The bobbin hook catches this thread and caries it around about 2/3 of a circle..  The tensioning lever rises and pulls up the extra slack.


Next thing:  Try a search on youtube for your make and model of sewing machine.  

There are sewing machine shops all over. you did not give any indication if you live on the moon, as there are none there, but I would be willing to bet there is one near you.   Take it in,  they will fix it. this is an inexpensive repair and just general maintenance.. timing is EVERYTHING  it may have skipped a tooth on the belt or it may just have an adjuster out of alignment in the bobbin which lines up, as the needle comes down to engage.  Not a bad thing to have them blow out the fabric fibers and re oil everything.

If the bobbin is not hooking the thread usually this is an issue of the needle bar needing to be adjusted. An easy way to check this is loosen the needle and and lower it in the groove a little bit and re tighten it. if that works there is typically a screw that holds the needle bar in place loosen this and and drop the needle bar a little bit. Be sure and raise the needle to it's original position!

Ok for starters can we just get the nomenclature straight.
1.  Just because a belt has cogs on it does not mean it is a timing belt!  Yes it will be a cog belt but that does not mean that it has any function as a timing belt.  Sometimes it is just a non-slip belt  But that does not mean that it necessarily is used for any "timing purpose" where two shafts have to have coordinated movements.  Calling it a "timing belt, if it is not used for timing may interfere with getting a correct answer.  Sometimes even the person who wrote the manual is so naive about this as to merely generate and spread confusion.   ......... Cog Belt....OK ..... Timing belt ?..... Maybe!!!  

2.  If it really really is used as a "timing belt", unless designed by idiots, there should be some kind of indexing feature on or around the cog pulleys connected by the belt  These may be as simple as small punch marks on the pulleys that have to be lined up with each other or specific marks on the machine frame etc. when the machine is assembled or the belt replaced.  And the pulleys have to be securly locked to the shafts they are on by a key or pin, etc.     Also any slack that is in the belt has to be taken up on the "slack" side of the belt. and this is usually provided for by a belt tensioner device of some sort.  So my first question would be, "have you looked for such timing marks and are the pulleys rigidly aligned on the shafts that they fit on?".  

On the cheap, but not necessarily bad,  the pulley to shaft alingment might be done with a pin (e.g. a roll pin) that goes through the hub and the shaft, but in this case it is possible to get the pulley on 180 degrees out of position.  The closer to fool proof approach is to have a key that fits into a slot in the shaft and into a corresponding slot inside the hole through the pulley hub.   Beware tha sometimes the key is locked into place by a setscrew.  And sometimes some idiot will loose the key and so just runs the setscrew in until it engages the slot in the shaft or aggggh somewhere else on the shaft.   If you find that you have any of this on the pulley/shaft system on your sewing machine, one or more close up photographs would sure help especially if they are not the grainy awful photos that some cell phones take.  

The fact that the machine has both a rotary bobbin and a cog belt certainly implies that it is not likely an ancient machine and may be well worth the repair issue if it appears otherwise well made.    

You were a little vague about what sort of timing issue you thought the machine might have, so a bit more elaboration about what sort of malfunction it is experiencing might well help to get a better evaluation.  

Best of luck, I hope that helps.