I HAVE HUNDREDS OF TIE TACKS, TIE BARS AND CUFF LINKS. cuff links: 0.67" x 0.67" (11/16" x 11/16" or 17mm x 17mm). tie tack/bar: 1.74" x 0.38" (1-3/4" x 3/8" or 44mm x 9.5mm). collar bar: none. 0.25" = 1/4" or 6mm - pretty small for standard button holes.
