If you are a machine quilter then you must use safety pins to baste together the layers of your quilt. Safety pins should be pinned about 3 inches apart all over the quilt top to ensure that the layers will not shift. You will need a couple hundred pins when basting a lap quilt.
Do not baste your quilt with a needle and thread and then try to machine quilt it. This will only result in heartache. The basting thread will get caught on every protruding part on your machine. You will end up having to baste the quilt top again. (Safety pins will also hang up on protruding parts but will not come out when you pull.)