tickThickness: Number

Sets the thickness of the tick marks drawn for the axisY stripline’s labels when the labels are placed outside.

var  chart =  new  CanvasJS.Chart("container", {
 .
 .
 axisY:{
	stripLines: [
		{
		 tickThickness: 5
		}
	]
   },
 .
 . 
});
chart.render();