Tapping aluminum

General tips/tricks/tools that could be utilized on any platform.
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Leatherneck
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Tapping aluminum

Post by Leatherneck » Thu Mar 26, 2020 1:08 pm

Is it better to fine thread or course when tapping aluminum? Thank you.

Ol'fogasaurus
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Re: Tapping aluminum

Post by Ol'fogasaurus » Thu Mar 26, 2020 3:18 pm

Leatherneck wrote:
Thu Mar 26, 2020 1:08 pm
Is it better to fine thread or course when tapping aluminum? Thank you.
Depends on the AL.

https://www.thoughtco.com/aluminum-or-a ... oys-603707

This is a basic list of the alloys and the components in each alloy. Add to that there is the temper of each alloy going from -0 to -6 or -8 (I think -8 is the strongest alloy I worked designed to). An example might be 2024- T6 to which the part may be designed to be formed in a -0 condition then heat treated to a -T6 condition.

https://www.practicalmachinist.com/vb/c ... um-235446/

This might give you some additional thoughts on threading. Machining vs. tapping is very different as the threads are shaped differently.

https://www.eng-tips.com/viewthread.cfm?qid=39629

Another set of thoughts on AL.

http://www.shender4.com/thread_chart.htm

A thread tap chart.

I could go on I think but this might give you a basis for search.

Lee

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Leatherneck
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Re: Tapping aluminum

Post by Leatherneck » Thu Mar 26, 2020 3:25 pm

Ok, let’s say I know bumkiss about the alloy it’s something I found in the metal pile, what say you Lee? Just pick one.

Ol'fogasaurus
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Re: Tapping aluminum

Post by Ol'fogasaurus » Thu Mar 26, 2020 7:12 pm

Do you know what the AL stock actually is? What is it going to be used for and if you have a choice of material what kind of loads do you expect it to be used for and how thick is it?

Lee

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Re: Tapping aluminum

Post by Ol'fogasaurus » Thu Mar 26, 2020 7:47 pm

Do you know where the stock came from or what it was used for? It is a hard question to answer.

Lee

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Re: Tapping aluminum

Post by Ol'fogasaurus » Thu Mar 26, 2020 8:39 pm

Without knowing a lot more: if it is a thick piece of stock/material and you are putting a big load on it then I would suggest that you go with less threads per inch. The threads would be stronger due to the thicker material in the threads.

Lee

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Leatherneck
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Re: Tapping aluminum

Post by Leatherneck » Thu Mar 26, 2020 8:57 pm

Yes will be thicker and more of a stand then support. Thanks Lee.

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sideshow
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Re: Tapping aluminum

Post by sideshow » Thu Mar 26, 2020 9:42 pm

I suggest matching the bolt threads, and use a common thread to the rest of the device. Fine thread while in theory generally isn't used as galls and crosses easier (harder to make well).
Yeah some may call it overkill, but you can't have too much overkill.

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Leatherneck
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Re: Tapping aluminum

Post by Leatherneck » Fri Mar 27, 2020 11:57 am

Gotcha, I will use that “ keep it similar “ thought in the other. Looking through my 20 year can couldn’t find enough fine thread bolts in that size. 😢

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GS guy
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Re: Tapping aluminum

Post by GS guy » Sun Mar 29, 2020 8:37 am

I generally use coarse thread in AL, unless the material is thinner - like 1/8" or under. Also use 70-75% thread height drill sizing and a good cutting fluid for both drilling and tapping.
Jeff

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