If I order 19ft of the 1/2" lead screw will it come in three 6'5" lengths by default? This is what I need. Thanks

No they will not come in that length as a default, we would contact the buyer to ask specific lengths due to the total length purchased. However if you order the 1/2" lead screw we can get them cut to the specific length you require, by contacting us here or call us at 281-815-7701.