These handy drill jigs have the proper spacing to fit MS21051 Single-Lug Nut Plates.
To use, simply drill the hole for your bolt or screw (where the nut will be). Insert the larger lug of the tool into that hole and tap the tool with a hammer. The single small lug acts as a transfer punch, locating the first rivet hole. Drill that hole, then flip the tool over (or insert the tool from the other side of the panel) and insert the tool with the two lugs in the two holes. Drill through the bushing on the tool to locate the last rivet hole perfectly.
Sizes 06 through 10 have 0.344" rivet spacing; 1/4" size has 0.5" spacing. All sizes have a hardened tool steel bushing for a #40 drill bit.* Each size has its own handle style for quick identification. Sold individually.
* A #40 bit will drill the appropriate size hole for a 3/32" rivet. The 1/4" jig can also be used for 5/16" and 3/8" nut plates, but you must ream the rivet holes to 1/8" diameter.
Note: Fits standard-size MS21051 and MS21061 nut plates only. Does not fit MS21071 "Mini" nut plates.