The adjustable warp springs shown in the detail image allow the spacing between the warp threads to be adjusted to any size bead. The threads can also be adjusted as you work to allow for precise accommodation for subtle changes in bead size as you work. Because you can snug up the spacing between the warp threads, when you "park" a row of beads between the threads, they will stay put until you can cross sew them.

The  detail image also highlights the thread anchors evenly spaced across the back of the loom head to hold the warp threads. Anchoring the threads evenly across the loom head maintains consistent tension.