You only get notified (via an event) when the Interval is expired - the Tick event is raised. If you want to "do some job" at 50ms then you need to set the Interval to 50, not 1000, but you had better make sure that the "job" is pretty quick, or you aren't going to keep up. If you mean that you have an Interval of 1000ms and you want to "do some job" every 50 seconds, then that's easy:
private int ticksCount = 0;
void myTimer_Tick(object sender, EventArgs e)
{
ticksCount++;
if (ticksCount >= 50)
{
ticksCount = 0;
DoSomeJob();
}
}