Topic: I want to thread a 7/16" 6061 aluminum bar,what die size should I use ?

[grcamna2]

I have this 7/16" aluminum bar that I will be using to make 2 fairing brackets.I don't have a tap & die chart & looking online hasn't helped me yet.. I have a set of metric tap and dies but not an SAE set.I want to use the exact best size for this application,coarse threads will be best. Any ideas ?

[Alan F.]

External threads require some calculation to derive info like that, from what I've read charts aren't available...?

Look up the relationship between Major Dimeter and Minor Diameter. 7/16= .4375

But then I found this chart:
http://www.carbidedepot.com/formulas-tap-standard.htm

[754]

External , is easy 10mm is.10mm. 3/8 I s 3/8..
 I most cases or ideal you will would end up 3 to 5 thou under ( die will take care of it ).. but for practical purposes  the size is  the size.

[calj737]

It’s completely elementary to calculate: 7 divided by 16 = .4375
10mm is 10 / 25.4 = 0.393
7/16 is closer to 11mm. Good luck finding a tap for coarse 11mm. Buy some 10mm rod and be done with it.

[grcamna2]

It’s completely elementary to calculate: 7 divided by 16 = .4375
10mm is 10 / 25.4 = 0.393
7/16 is closer to 11mm. Good luck finding a tap for coarse 11mm. Buy some 10mm rod and be done with it.

I purchased a 7/16-14 Die online after I received advice that 7/16" is the correct size Die to use to thread 7/16" O.D. rod.I will not "buy some 10mm rod" because 7/16" O.D. is the correct spec for my fairing mount clamp/brackets which slide over the two rods and then clamp-down onto it.I will need to drill 4) holes in the fairing(through the black gelcoat finish)to attach the clamps and 2) lower brackets which mount to the headlight ears.This is to mount a black Maier  GP sport fairing pt.#511 made for a 7" round headlight.I purchased this one from Dennis Kirk in 2016'.