Looking at the end of your sewing machine, measure across the base, sides and top as shown in the picture. Allow a 1/2' to 3/4" of ease rather than snug measurements.
For the machine shown here, due to the angles, I found it easiest to hold a piece of newspaper print paper to the end of the machine and fold the paper to the size I wanted on the end of the cover and then add 1/2" seam allowances to three sides of the pattern.
Draw the desired size on a piece of paper and add 1/2" to all of the sides except the bottom.
This is the pattern for the ends of the cover.
Using the lines indicating the finished size of the end pattern piece, find the total of the height, across the top of the pattern piece and the second height. A+B+C = Sum
Fold the top of the pattern in half and continue the fold down the pattern piece. Use this fold as a straight grain line to layout and cut two of this piece.