THE START IS THE SAME FOR ALL CYLINDERS.
We trace the axes of the upper part, with an angle between them of 60 degrees.
The upper parts are drawn, because half of the lower ones will be hidden.
We take the measurements of the spokes on the axes, measuring from the center.
We draw the diamonds, where we will inscribe the ovals of four centers, or circumference in isometric perspective. We draw their major diagonals.
We join the lower midpoints with the upper vertices, to find the two centers of the missing oval, on these diagonals.
To draw the lower circumference, the center is moved according to the heights of the cylinders.
We trace the axes of the lower part, parallel to the upper ones. And we also draw the major diagonals.
We draw only half of the lower ovals, for that we lower 3 of its 4 centers. With the same distances of the heights of the cylinders.
We trace these semi-vaults with the new centers and the same radios used above.
The axes will determine the points of links.
We finish the cylinders joining their two bases with tangent lines.

Cylinder first.
On the upper axes we mark the width of the slot. Where it is cut with the oval, its depth is drawn.
We lower the centers this same measure.
To draw the oval sector of the slot, the radius is picked up with the compass, and the measure of its depth is transferred.

Cylinder second.
Also on the upper axes, we mark the measurements of the width and length of the slot. It ends the same as the previous cylinder.

In the third cylinder, we must draw a new interior oval with the same start procedure. we lower the indicated depth, by lines parallel to the upper drawing.

Fourth cylinder.
At the top, we draw the line of the cut.
at the intersection with the oval, its depth is lowered.
To finish, we must lower two centers of the upper oval, the same depth measurement, to draw the section of the oval of the cut.
On this plane we mark the axes and draw the oval of the perforation.

Cylinder fifth.
We must draw another interior diamond with the measure of the radius of the inner circumference.
We trace his oval.
At the top, we draw the line of the cut.
at the intersections with the ovals, the thickness of the opening is plotted.
We must go down two centers of the small oval, to draw the inner oval that lets us see the opening.

The sixth cylinder is made in the same way as the fourth. But now we draw two side cuts.
We need to draw another oval, lowering the four superior centers, the measure of the depth of the cut, and with the same radii the new oval is drawn.
And to finish it, the necessary lines are drawn so that it has the logical volume.
The solution cylinders are drawn to a greater thickness.
It is very important to leave all the auxiliary lines, (NOT CLEAR ANYTHING), so that the teacher can check the work done.