What size hole for a 1/4-20 rivet nut?

It depends on the body. A 1/4-20 flat head (smooth round body) rivet nut takes a Q drill (.332″ hole); a 1/4-20 ribbed rivet nut takes a 25/64 drill. Drill what the package calls for.

What drill size for a 3/8-16 rivet nut?

A 3/8-16 ribbed rivet nut (large or small flange) takes a 17/32 drill. A 3/8-16 half hex rivet nut needs a .500″ hex hole (across the flats).

What does grip range mean on a rivet nut?

The grip range is the total thickness of the material the rivet nut is set in — every sheet it clamps, together. Pick the rivet nut whose grip range takes in your thickness.

Why does my rivet nut spin in the hole?

Most often the hole is too big. Each style is made for a tight hole: drill exactly what the maker calls for. Ribbed and hex bodies resist spinning better than smooth round bodies.

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Rivet Nut Sizes

Inch rivet nuts by thread: grip range, body length, head diameter and the hole to drill for flat head, ribbed (large and small flange) and half hex rivet nuts.

A rivet nut (rivnut, threaded insert, blind rivet nut) puts a threaded hole in thin metal or tubing. It goes into a drilled hole from one side and the tool pulls the threads up, so the body bulges behind the sheet and clamps it; then a screw can go in and come out again. A rivet nut is sized by its thread and its grip range — the thickness of material it is made to clamp — and each body style is made for its own hole size.

The labels match the table columns. Not to scale.

Jump to: Flat head · Large flange ribbed · Small flange ribbed · Half hex

Flat head rivet nuts, smooth round body — heavy wall
Thread	Grip range	Body length	Head dia	Hole (min)	Drill
#4-40	.010–.060	.345	.270	.155	—
#4-40	.060–.085	.370	.270	.155	—
#6-32	.010–.075	.438	.325	.189	#12
#6-32	.075–.120	.500	.325	.189	—
#6-32	.120–.160	.500	.325	.189	—
#8-32	.010–.075	.438	.357	.221	#2
#8-32	.075–.120	.500	.357	.221	#2
#8-32	.120–.160	.500	.357	.221	—
#10-24	.010–.080	.531	.406	.250	—
#10-24	.080–.130	.594	.406	.250	—
#10-32	.010–.080	.531	.406	.250	1/4
#10-32	.080–.130	.594	.406	.250	1/4
#10-32	.130–.180	.641	.406	.250	—
1/4-20	.020–.080	.625	.475	.332	Q
1/4-20	.080–.140	.687	.475	.332	Q
1/4-20	.140–.200	.750	.475	.332	Q
5/16-18	.030–.125	.750	.665	—	—
5/16-18	.125–.200	.875	.665	—	—
5/16-18	.200–.275	.937	—	.413	—
3/8-16	.030–.115	.844	.781	—	—
3/8-16	.115–.200	.938	.781	—	—
3/8-16	.200–.285	1.031	.781	.490	—
1/2-13	.050–.150	.906	.906	.625	—
1/2-13	.150–.250	1.031	.906	.625	—
1/2-13	.250–.350	1.141	.906	.625	—

Inches. Steel and aluminum share a row. Printed where every maker that lists the row (AVK, Marson, Sherex) gives the same value; a dash: they differ, or one gives two values — drill what the maker’s package calls for, or give us a call. Hole (min) is the smallest hole the makers give; the drill is the one they name.

Large flange ribbed rivet nuts — ribbed / knurled body
Thread	Grip range	Body length	Head dia	Drill
#6-32	.020–.080	.420	.390	17/64
#6-32	.080–.130	.470	.390	17/64
#8-32	.020–.080	.420	.390	17/64
#8-32	.080–.130	.470	.390	—
#10-24	.020–.130	.475	.415	19/64
#10-24	.130–.225	.585	.415	19/64
#10-32	.020–.130	.475	.415	19/64
#10-32	.130–.225	.585	.415	19/64
1/4-20	.027–.165	.580	.500	25/64
1/4-20	.165–.260	.680	.500	25/64
1/4-28	.027–.165	.580	.500	—
1/4-28	.165–.260	.680	.500	—
5/16-18	.027–.150	.690	.685	17/32
5/16-18	.150–.312	.805	.685	17/32
5/16-24	.027–.150	.690	.685	—
3/8-16	.027–.150	.690	.685	17/32
3/8-16	.150–.312	.805	.685	17/32
3/8-24	.027–.150	.690	.685	—
3/8-24	.150–.312	.805	.685	—
1/2-13	.063–.200	1.150	.865	—
1/2-13	.200–.350	1.300	.865	—

Small flange ribbed rivet nuts — low profile head, ribbed / knurled body
Thread	Grip range	Body length	Head dia	Drill
#6-32	.020–.080	.420	.310	17/64
#6-32	.080–.130	.470	.310	17/64
#8-32	.020–.080	.420	.310	17/64
#8-32	.080–.130	.470	.310	—
#10-24	.020–.130	.475	.340	19/64
#10-24	.130–.225	.585	.340	19/64
#10-32	.020–.130	.475	.340	19/64
#10-32	.130–.225	.585	.340	19/64
1/4-20	.027–.165	.580	.455	25/64
1/4-20	.165–.260	.680	.455	25/64
1/4-28	.027–.165	.580	.455	—
1/4-28	.165–.260	.680	.455	—
5/16-18	.027–.150	.690	.595	17/32
5/16-18	.150–.312	.805	.595	17/32
5/16-24	.027–.150	.690	.595	—
5/16-24	.150–.312	.805	.595	—
3/8-16	.027–.150	.690	.595	17/32
3/8-16	.150–.312	.805	.595	17/32
3/8-24	.027–.150	.690	.595	—
3/8-24	.150–.312	.805	.595	—

Half hex rivet nuts — large flange, hex body
Thread	Grip range	Body length	Head dia	Hex hole (across flats)
#6-32	.020–.080	.385	.375	.250
#6-32	.080–.130	.435	.375	.250
#8-32	.020–.080	.385	.375	.250
#8-32	.080–.130	.435	.375	.250
#10-24	.020–.130	.435	.390	.281
#10-24	.130–.225	.535	.390	.281
#10-32	.020–.130	.435	.390	.281
#10-32	.130–.225	.535	.390	.281
1/4-20	.027–.165	.585	.510	.375
1/4-20	.165–.260	.685	.510	.375
3/8-16	.027–.150	.685	.655	.500
3/8-16	.150–.312	.845	.655	.500

Inches. Steel and aluminum share a row. Printed where every maker that lists the row (Marson, Sherex) gives the same value; a dash: they differ, or one gives two values — drill what the maker’s package calls for, or give us a call. The hole is a hex: cut or punch it to the size across the flats.

Good to know

Grip range is the total thickness of everything the rivet nut clamps. Too thin for the grip range and it won’t clamp tight; too thick and it won’t set.

Drill the hole the maker’s package calls for: each style is made for a tight hole, and too big a hole is the number one reason a rivet nut spins. Ribbed and hex bodies resist spinning; a large flange spreads the load; a small flange sits nearly flush.

Torque and loads (install torque, pull-out, spin-out) depend on the maker, the material and the hole — they are not on this chart. The makers ask for trial installations in your material to confirm the grip.

Not on this chart: thin-sheet (swaging), bulbing / slotted, low-profile poly, expander, closed end and metric rivet nuts — fewer than two of our makers list them the same way. Their TECH DATA sheets give the part’s listed sizes.

Quick answers

What size hole for a 1/4-20 rivet nut?: It depends on the body. A 1/4-20 flat head (smooth round body) rivet nut takes a Q drill (.332″ hole); a 1/4-20 ribbed rivet nut takes a 25/64 drill. Drill what the package calls for.
What drill size for a 3/8-16 rivet nut?: A 3/8-16 ribbed rivet nut (large or small flange) takes a 17/32 drill. A 3/8-16 half hex rivet nut needs a .500″ hex hole (across the flats).
What does grip range mean on a rivet nut?: The grip range is the total thickness of the material the rivet nut is set in — every sheet it clamps, together. Pick the rivet nut whose grip range takes in your thickness.
Why does my rivet nut spin in the hole?: Most often the hole is too big. Each style is made for a tight hole: drill exactly what the maker calls for. Ribbed and hex bodies resist spinning better than smooth round bodies.

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