That said, they are very close, the 3/8″ bolt is about 0.019″ smaller and the pitch’s are very close so the 3/8 -16 bolt will thread in the 10mm x 1.5 but the 10 x 1.5 bolt will not fit the 3/8 but..Click to see full answer. Herein, are m10 and 3/8 the same?Since 10 mm is bigger than 3/8″, the simple answer is, “NO”. But you CAN drill the hole out to either 25/64″ (for 3/8-24) or letter “X” (. 397″)( for 3/8-16), and tap for a Helicoil.Additionally, is m10 the same as 10mm? The M8 will measure about 8 mm in diameter, more likely, just a touch undersize, (. 31496″) The M10, about 10 mm in diameter, (. 3937″) and the M12 about 12 mm in diameter, (. In this example the bolt is 10 mm in diameter, 40 mm long, and the threads are 1.25 mm apart. Accordingly, what size is a 3/8 bolt in metric? Fastener Conversion Chart Inch Equivalent Metric Size-PitchISO and IFI Rec. 10- 24 10- 32 M5x .8 1/4- 20 1/4- 28 M6x 1 5/16-18 5/16- 24 M8x 1.25 3/8-16 3/8- 24 M10x 1.5 Are m5 and 10 32 interchangeable?10/32 is slightly smaller in diameter than M5. You can use a 10/32 screw in an M5 nut pretty safely. The inverse is not true.