An Elastic Stitch Hemmer works great for sewing elastic end to end while preventing bunching.

Guaranteed to fit Brother Sewing Machine Models:
B837

Guaranteed to fit Juki Sewing Machine Models:
DNU-1541, LS341, LU-562, LU-563, LU-1114, LU1508, LU-1510, LU-1560

Guaranteed to fit Singer Sewing Machine Models:
111G, 111W, 153K101, 153W101, 153W103, 168W, 211G, 211U, 211W