Although it may initially look complicated to change the long leather belt on a treadle (pedal) sewing machine, it's actually very simple, and can easily be done by the average person using tools that are common around most households. My directions will seem more complicated than the procedure actually is.
Tools needed; a sharp knife or large scissors, an ink pen or Sharpie marker, a 4d-6d finish nail or a sharp ice pick or punch about the diameter of a pencil lead. A pair of pliers.
Clip the old belt in two (if it's still present) These belts generally last a long, long time under the right conditions. I have seen 100 year old treadle belts that still worked! However, they eventually dry-rot or just break.
The machine should be in the up (working) position.
Fold the new belt in the middle, and place it over the top of the handwheel of the machine. There will be two holes on most machine's cabinets directly under the handwheel, and immediately to the right of the machine base. Half the new belt goes in the front hole, and half in the back hole. Push it all the way down so that it comes down over the handwheel and lays in the belt groove, which will be to the left of where you grasp the handwheel, and be smaller in diameter. You may have to work the belt around the bobbin winder or belt guard to get it into the right place.
Now get on your knees and peer up underneath the cabinet. You will of course see the two long ends of the belt that you just pushed through from above. The object is to get the back half looped around the large pulley underneath, and pulled up toward the front of that pulley so it can be measured and marked. This takes a little doing, especially the first time. No, no, go ahead and get the belt on and don't stop to clean out all the dust and cobwebs that you see under there!
On some machines there will be metal loops immediately above the front and back of that large pulley that the belt must go through before looping around the pulley for measuring. Most Singer machines only had one hinged loop in front. Be sure the belt gets through the loop(s) Then work the back half of the belt around the back and bottom of the large pulley. To get it all the way around you will have to pull it farther down and give some slack on the front half of the belt.
Being sure the belt is still correctly around the machine handwheel, and that it's looped around the large pulley underneath, and through all the loops and holes it's supposed to go through, then pull it up snug, let the ends lap, and mark the end that does not have the metal staple in it.
Some folks take the belt back off at this point, others just work with it while on their knees. You'll have to at least flip it loose from the large pulley to give yourself some working slack. Cut the excess belt off at your mark. on most machines you'll wind up cutting off about 4"-8" of belt. Note how that metal staple is fastened in to the other (uncut) end, and punch a corresponding hole in the cut end of the belt. Try to get the hole centered in the belt material.
Put the belt back in place, hook the staple through the hole you just punched, then using your pliers pinch the open end of the staple down onto the belt. You've done it!
The goal is to have the belt tight enough so that it doesn't slip much, but not so tight that it makes the machine difficult to pedal. After a few months you may have to clip some more off, as the leather may stretch some. After that, it will be good for decades!
We carry a supply of good quality treadle belts in our online catalog at http://www.vintagesingersewing.com/. We also have bobbins and shuttles for a lot of the old machines.
