Aluminum Hole distance from center to edge of part?

[ecope]

Hello,

I know that if you are tapping aluminum the rule is twice the depth of the dia. hole. But what is the rule from center of hole to edge of part? Is the rule still 1-1/2 times the dia. or is it twice?

Maybe I am wrong altogether, but I need to know!

Thanks!

 

[hydtools]

I use 1x to 1.5x the nominal diameter.

Ted

 

[unclesyd]

We use a lot of Al tooling plate where we use 1 1/2x bolt diameter up to 1/2" and 2x for 1/2" and above.

 

[limey1]

Is there any stress in this application?. If the hole isnt pre-stressed before tapping, I believe a minimum of 1.5 is the general rule.