# drain hole for turbo



## OZMAN (Apr 1, 2003)

SUP guys i know i have to use a 1/2 inch npt tap for the hole in the block but what size drill bit do you use for the final hole before you tap the the threads,i dont want to go to big if yiu know what i mean thanx...


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## James (Apr 29, 2002)

http://www.efunda.com/DesignStandards/screws/tapdrill.cfm


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## lshadoff (Nov 26, 2002)

23/32 in. 

Here's how I did it without removing the radiator.

Lew


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## James (Apr 29, 2002)

23/32 is .71" lew, I don't think you can tap anything else after that...


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## lshadoff (Nov 26, 2002)

James said:


> 23/32 is .71" lew, I don't think you can tap anything else after that...


http://www.carbidedepot.com/formulas-tap-pipe.htm

Lew


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## James (Apr 29, 2002)

hmm... sorry not thinking.


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## javierb14 (Jul 9, 2002)

lshadoff said:


> 23/32 in.
> 
> Here's how I did it without removing the radiator.
> 
> Lew


good info :cheers:


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