What size drill bit

[ACC]

I am experimenting and need a drill bit that is close to .358 inj diameter. What fractional drill bit is close.

ACC

[sparkyv]

23/64" is 0.359". Is that close enough?

[FLINTNFIRE]

You would want a T size

[M-Tecs]

This chart shows you what available in letter, number and metric in addition to fractional. Drill bit always drill oversize and they don't produces perfectly round holes. 1% to 5% oversize is normal for drill bits finished hole sizes.

https://www.abbottaerospace.com/wp-content/uploads/2017/02/Inch-and-Metric-Drill-Bit-Size-Chart-1.jpg

[Moleman-]

drill undersize and use a reamer.

[JonB_in_Glencoe]

You may get better advice if you told us your plans.

If you are removing a GC shank from a 358 mold, something I have been thinking about doing, you can search Ben's posts, as he has done that and has a real good technique that your average Joe can do with a drill press...and he used a 23/64" HSS Straight Shank Straight Flute Chucking Reamer, which isn't much more expensive than a real good drill Bit.

If you are doing that, or something else but still having to do with mold cavities, be aware that standard Drill bits don't make round holes.