Whether a crust is flaky or not doesn't depend on the type of fat (though it does to some extent, with shortening/lard giving a more flaky crust because they don't have water in them) as much as it depends on the size of the fat pieces which are combined with the flour.
For flaky crusts, you want to combine the fat with the flour only until the mixture gets to the size of small peas. The larger sized peices of fat melt and create steam as the crust cooks, which, in turn creates layers of flaky crust.
For a short crusts ("crumbly" "mealy"), you need to combine the fat until the peices are much smaller. Like cjs's recipe says -- till they resemble coarse cornmeal. cjs's recipe looks like a good one for a short (or "crumbly") crust.
DO NOT knead more!
Consider replacing a t of water with vinegar for a more tender crust.
Fats: The differences in textures of many pastries has to do with the type of fats and how it's introduced. Fats contribute to the tenderness (shortness) and especially flakiness of pastry. Pure fats, such as shortening and lard, produce to flakier pastry than those that contain water such as butter. Pastry is often a trade-off between flavor and texture, much of which comes from the fat in the recipe. Some bakers use both butter and shortening to capture the best qualities of each, but I prefer to use all butter because of its better taste.
Fats contribute to the flakiness and tenderness of pastry by being layered in between sheets of thin dough. It can also be cut in or rubbed into the flour as pea-sized shapes before the final dough is made. The fat melts during baking, leaving air spaces. When placed in the oven, the flour starches set around the fat, leaving a layer or space when the fat melts which is reabsorbed back into the dough. The longer the fats take to melt in the oven, the more well defined the air cells. The melting point of shortening is higher than that of butter, and it stays solid longer. As a result, it forms better flaky pastry, but without the butter's wonderful flavor."
Less is not more. More is more and more is fabulous.