Needle notes...

The regular sewing machines all take type 130/705H (also known as 130R, 15x1 or HAx1 needles).

The Elna 704DEX serger takes ELx705 needles. This is a Schmetz variant on the 130/705H needle designed for Elna cover stitch sergers, but should perform well in any serger that uses 130/705H needles (and is worth trying if your serger that uses regular needles is being flaky). Other manufacturers also make ELx705. Size 11-14

The BabyLock (Juki) BL4-738D serger takes DCx1F needles. Size 11,14

The Singer 14u13 serger takes Singer #2053 (Organ type JLx1) needles. Size 10-14

More needle notes...

...because I'm sick of paying $5 for a card with 5 needles, and running out.

Organ DCx1F serger needle, 100 pack
CTS: $89.95
Diamond Needle: $44.90
AllBrands.com: $49.99

Organ SY2922 (ELx705) serger needle, 100 pack
CTS: $34.95
Diamond Needle: $31
AllBrands.com $34.99

Schmetz ELx705 serger needle, 100 pack
AllBrands: $40

Organ JLx1 serger needle, 100 pack
CTS: 45.95
Diamond Needle: $26