End grain turning

It is possible to turn end-grain bowls; it's just not a good idea. An end-grain cup has the grain of the wood running up the height of the cup, an arrangement which utilises the strength of wood along the grain. A bowl is usually wider than tall, so the shape runs across the grain, resulting in a weak structure. Also, if you use the log in the round, you will certainly get a radial crack opening as the wood seasons.

Bowl turners ideally start with a log the same length as its diameter and cleave it in half so the cleft faces are roughly square, then round off each square face with a side-axe before putting it on the lathe. Having the grain running across the bowl results in a much stronger structure, with only two weak points on opposite rims, but that's inevitable with straight grain across a circular bowl.

Of course, you may already have found this out by trial and error, as you have been waiting nearly six weeks for anyone to post. :-)