Is 21/64 a standard shaft diameter? I have never heard of it but recently bought some shafts marked in that diameter. Are field points available? I am familiar with 23/64, but this size is new to me.

I ran across this a while back and have seen several Bear arrows advertised in that size. Don't know about point availability though...

11/32" points will work fine.

We have some 21/64 nocks and a few 21/64 points

5/16 is 1/64 smaller and 11/32 is 1/64 larger, use eiter one and dont worry about it. Not building NASA rockets here, just arrows. 21/64 size nocks and points are for aluminun arrow sizes 2117,2115,2114,2113,2112................

21/64 shafts were made in the 40s and 50s, maybe later as well, but haven't been made recently. As has already been pointed out 5/16 and 11/32 components will work just fine.

Thanks! I've got plenty of 11/32 points on hand. Nocks don't matter, as I'm going to try to do self nocks to shoot off my English longbow.