Need Help : Scanning a drawing template and converting it SVG file

I need help on taking my drawing template and adding it to the x carve. What are some accurate methods to do for this? i tried drawing my tools shape then scanned it to the computer. Using the computer to make vector lines but the size of the tool changes. What is the reason for that?

My solution for this is to lay out the tools on a grid of a known size, then photograph that — a square or a ruler can be used instead. Then import the image, scale it so that the grid/rule are the correct size in the drawing program, then draw. Tutorial on this on the wiki: https://wiki.shapeoko.com/index.php/Carbide_Create_Photo_Tracing — but you can use any drawing program which will allow you to place an image and scale it. Just make sure that the scale/size is preserved when importing into your CAM program (I like to draw a rectangle of a known size first).