Repair Sewing Machines: White Futura 464
It is important to understand the operation of a sewing machine from the standpoint of stitch formation and the design type of the machine. Here we have a classic sewing machine with a side loading bobbin and an oscillating hook.
When we understand the key elements going into how the stitches are formed, it becomes quite easy to adjust the machine. For example, tensions consist of two thread sources with various guides, tensioners, twists, and turns. One thread comes from above, and the other from below. If the resistance on both top and bottom are equal, the thread will from a stitch knot inside the fabric. If either one pulls harder than the other, that side of the fabric will collect excess threads. The same principle applies on this machine and virtually every other lockstitch sewing machine ever made.
The stitch selection may vary from machine to machine, but the function remains the same on most mechanical machines. A lever is used to increase or decrease the stitch length. On most machines stitch width and variations are added in similar fashion.
Sewing machine timing is not just a single adjustment. Instead it involves the alignment of needle bar assembly, feed dog assembly, and hook assembly. All three must be adjusted to work together.
For Videos On Sewing Machine Repair check out the following:
Fix Sewing Machines Institute http://youtu.be/g6v-zOjIK1M
Sewing Machine Disassembly http://youtu.be/KqdGGQwjwiA
Sewing Machine Repair http://youtu.be/KABZ6Zo8AH4
Invention Of The Sewing Machine http://youtu.be/_LBWar-MF6A