question about plugging a hole in aluminum

[sixto]

What size threaded plug should I use in a 21.4mm untapped diameter hole in aluminum?

I'd prefer to use a freeze plug but I can't find anything that fits. 7/8" is really close but really close doesn't work :/

Thanks,
Sixto
87 300D

[t walgamuth]

Buy a tap that works for the size of the hole and buy a plug that matches. YOu weren't thinking of putting in the plug wo tapping it were you?

Or maybe I didn't understand the thrust of your question.

[Brian Carlton]

Drill it out to .922 and tap it for 3/4" NPT.