Problems cutting smooth threads in aluminum

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Darrell
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Re: Problems cutting smooth threads in aluminum

Post by Darrell »

Maybe the cutting fluid? Is it for aluminum?
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Aglifter
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Re: Problems cutting smooth threads in aluminum

Post by Aglifter »

What grade of Al? (I know nothing of machining other than some comments about our fabricator that "you can always tell 6061.")

Now, in dairy, we deal w. very soft, but very corrosion-resistant stainless, and everything is held together with clamps - would something like that work?
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Steamforger
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Re: Problems cutting smooth threads in aluminum

Post by Steamforger »

Oddly enough, WD-40 is an excellent cutting lube for Al. Are you using a quality insert with the right geometry for an Acme thread? Iscar or something equivalent? Acme is just unusual anyway. I think we cut them about once a year in soft stainless for Oil Field valves. Other than stubbing up your tool holders as much as you can get away with, and shortening the length of part hanging out of the collet as much as you can get away with, I don't know much more to add. Are you using a proper speed and feed with corresponding RPM for 6000 series Al? I'm sure you are but thought of that just as a double check. I know Doc Nickel will occasionally wrap tool holders in rubber bands to get that last bit of chatter out. I've never had to do that. I cut 304, 316, 17-4PH, Inconel and Monel during my shop days (some of that shit comes with its own headaches). I suspect HTRN will be a bit more helpful.
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Netpackrat
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Re: Problems cutting smooth threads in aluminum

Post by Netpackrat »

Take the biggest crescent wrench you have, and apply repeatedly to the designer. :mrgreen:
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Re: Problems cutting smooth threads in aluminum

Post by Aesop »

<------conspicuously not asking what you're doing threading multiple nested watertight AL tubes together, to maintain plausible deniability.
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Cobar
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Re: Problems cutting smooth threads in aluminum

Post by Cobar »

In my limited experience WD-40 works great when cutting Al.
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Netpackrat
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Re: Problems cutting smooth threads in aluminum

Post by Netpackrat »

Have you tried Boelube? The people who created it know a thing or two about cutting aluminum.
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Denis
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Re: Problems cutting smooth threads in aluminum

Post by Denis »

Random thoughts:

Try WD40, kerosene or aluminium "Tap-Magic" as cutting fluid.

Instead of carbide, use *really sharp* HSS cutting tools. Lap your own on a diamond stone, or buy Warner HSS inserts:

http://www.arwarnerco.com/c-6-standard- ... serts.aspx

Are you cutting V-threads to a sharp valley? Try rounding the apex (adjust your tool) a little instead to avoid galling. Edit - I see you mentioned Acme thread. Lower the plateau of the male thread, so it can't gall on the flat of the valleys.
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HTRN
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Re: Problems cutting smooth threads in aluminum

Post by HTRN »

Denis wrote:Try WD40, kerosene or aluminium "Tap-Magic" as cutting fluid.

Instead of carbide, use *really sharp* HSS cutting tools. Lap your own on a diamond stone, or buy Warner HSS inserts:
Yes to both - using carbide to thread in aluminum.. Yeah, two reasons why that isn't a great idea. One, Carbide is "dull" compared to HSS - it doesn't like very fine cuts(IE, less than .01) and it's terribly high sfm(starts at 1000 in AL) means you really should be cutting at speeds that you're lathe doesn't even go to, let alone what you're comfortable in.

Boelube works, as does that nasty Ridgid sulfurized pipe cutting oil(if you can still get it). Another option that I really like is A9 - we buy it by the gallon at work.
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Darrell
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Re: Problems cutting smooth threads in aluminum

Post by Darrell »

HTRN wrote:
Denis wrote:Try WD40, kerosene or aluminium "Tap-Magic" as cutting fluid.

Instead of carbide, use *really sharp* HSS cutting tools. Lap your own on a diamond stone, or buy Warner HSS inserts:
Yes to both - using carbide to thread in aluminum.. Yeah, two reasons why that isn't a great idea. One, Carbide is "dull" compared to HSS - it doesn't like very fine cuts(IE, less than .01) and it's terribly high sfm(starts at 1000 in AL) means you really should be cutting at speeds that you're lathe doesn't even go to, let alone what you're comfortable in.

Boelube works, as does that nasty Ridgid sulfurized pipe cutting oil(if you can still get it). Another option that I really like is A9 - we buy it by the gallon at work.
Relton A9 is what we use as well.
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