what kind of aluminum is best for threading?

[upTheHill]

I want to part and thread an aluminum rod and thread an aluminum tube for an air gun project I have been thinking about.
there will be 2 different tubes. 1 with an OD of 1.5" and a wall thickness of 0.065", the other tube having an OD of 1.0" and the same wall thickness, the rod would be turned and threaded to go inside the 1.5" tube, and a hole drilled and threaded for the 1.0" tube to go inside of it.

I was going to use 6061 for this, but was wondering if I should consider another kind of aluminum. is 6061 easy to thread? I want it to be lightweight, and it doesn't have to withstand a lot of pressure, that's why I'm thinking of aluminum, unless you think a different metal (or even Delrin) would be better. I will be doing this work on a Grizzly G0602 lathe I have on order, and I'm trying to have the material and tools ready for experimenting for when it arrives.

TIA, Dave

 

[Ray C]

6061 = very good threading material.

Anything softer and it gums-up.

Use WD-40 (or a mix of kerosene and auto trans fluid) as lubricant. You will get less sticking to the bit and a smoother cut. -Trust me on this. 80% of the marina parts I make are AL.

Edit: And the previous poster is correct too. Any 60xx AL will thread OK.

 

[upTheHill]

thanks for the info and links. I get my material from McMaster but hadn't seen that page you sent.
I was planning on a fine thread. I'm sure it will take many tries and practicing to get things down, but at least for mow, that's part of the challenge / fun.

Dave

 

[upTheHill]

Agreed. I always use WD40 when cutting aluminum. If you don't anodize, just keep some sort of lubricant on the threads when screwing/unscrewing. Even a coat of Johnson's paste wax helps.

What happens if the threads aren't coated?
rust / bind up?

for one part, that wouldn't be a bad thing, since I do not want them to come apart. I was going to apply loctite or a grub screw to hold everything in place.

 

[Ray C]

It's soft, easily cross-threads and also tends to bind-up like stainless steel. Keep the threads clean and put a light smear of vaseline on e'm. Grub screw is a mechanical fastner that usually damages aluminum surfaces. A locking collar (like a double-nut) might be a consideration. Loctite? Now that I think about it, I don't recall ever putting it on AL threads. Read the bottle and let us know. -There's probably different kinds suited for AL.


Ray

What happens if the threads aren't coated?
rust / bind up?

for one part, that wouldn't be a bad thing, since I do not want them to come apart. I was going to apply loctite or a grub screw to hold everything in place.

 

[upTheHill]

Loctite? Now that I think about it, I don't recall ever putting it on AL threads. Read the bottle and let us know. -There's probably different kinds suited for AL.

Ray

According to Loctite, the red (271) or blue (242) can be use on AL with no problem, the red is good up to 500 deg. and can only be removed with heat and force. just keep either away from any plastics or O2 rich environments was their only warning. so I'll try the red on and see how it works out.

 

[Ray C]

Do keep in-mind that AL is fairly soft stuff and not well suited for fine threading. Maybe draw a sketch of what you plan to make along with the intended thread rate and we can assess if you have a candle's chance in a windstorm of it holding up for more than 2 minutes.

 

[jgedde]

6061 = very good threading material.

Anything softer and it gums-up.

Use WD-40 (or a mix of kerosene and auto trans fluid) as lubricant. You will get less sticking to the bit and a smoother cut. -Trust me on this. 80% of the marina parts I make are AL.

Edit: And the previous poster is correct too. Any 60xx AL will thread OK.

+1 on the 6061. The 7000 series stuff threads very well too. Most of the 2000 series stuff I'v worked with is very gummy and the tool loads up if you don't "do the right thing"...

John