Choosing the right drill bit for rivet nuts, the size of the hole really matters. It ensures the strongest and safe connection for well installed rivet nuts. Hole too narrow or too broad can bad affect the output of the rivet nuts later
Use calipers to estimate the diameter of the rivet nut, and drill a bit bigger than the body of the rivet nut, some thousandths more. For instance, M8 large flange steel rivet nut measures correctly 13.44 mm, so 13.5 mm drill works. Other info shows that for M8 rivet nut 11.0 mm drill works.
Choose the Right Drill Bit Size for Rivet Nuts
Hence it matters to check the precise specifications for the used kind of rivet nut. Different grades require different sizes.
For 1/4-inch rivet nuts the results range similarly. Some 1/4-inch rivet nuts work best with 23/64-inch drill. It can seem a bit small at first, until you widen the hole out a little bit.
Some 1/4-20 aluminum rivet nuts require.332 to.338-inch drill, so letter Q. In test on scrap material with standard drill felt bad, virtually the rivet nut will pull through. Switching to 29/64-inch drill everything worked almost perfectly.
For 6 mm rivet nuts the right drill size is 23/64 inch. 4-40 threaded rivet nut is very small, so its body requires small diameter. In some cases you use 17/32-inch bit to expand holes for nutserts, while 3/8-inch drills go through mounting holes.
Size 3/16 you commonly choose for certain rivet uses.
The right kind of drill matters as much as the size. Use metal drill bits for rivet use, no masonry bits. After drilling clean the hole, turning the bit a bit around for good fit.
Stepped drill also works for such work. Start with the smallest available and go to the next size to help not drill too big a hole.
There is a tool in production that uses one drill designed for SAE and metric rivet nuts, covering 22 to 30 different sizes and brands of rivet nuts. That would simplify everything. Now even so always look at rivet nut drill size chart for precise specifications before drilling.
