Is there anything special that needs to be done or is it the same process as threading steel?:D

To my knowledge it's the same process just easier.:D

I threaded my bellhosing with a tap and it worked fine.

Tap Magic makes a formula specifically for aluminum. Whether or not it helps, I can't say for sure. But I haven't had any problems when I've used it.

cmk

depending on material, you can use a cutting or rolling tap.

Use lots o lube and go slow. Material can load up in the tap wipe out your threads as you cut them especialy when backing it out.

When tapping steel, you generally use a drill size that creates a 60% thread depth, on softer material, use a drill that makes a 75% depth. Most tap charts show both. I also use fine thread when I can in Aluminum.

Originally posted by Ramstein
Use lots o lube and go slow. Material can load up in the tap wipe out your threads as you cut them especialy when backing it out.


For a second I wasn't sure if you were talking about tapping threads or tapping... :D

Originally posted by zags
When tapping steel, you generally use a drill size that creates a 60% thread depth, on softer material, use a drill that makes a 75% depth. Most tap charts show both. I also use fine thread when I can in Aluminum.

Standard engineering practice is coarse thread in aluminum. this is strongest with most aluminum alloys.

Tap magic for Aluminum works awesome, but you can get by with any lube.

I have never had much luck hand tapping with the forming taps great for CNC though.

Originally posted by zags
When tapping steel, you generally use a drill size that creates a 60% thread depth, on softer material, use a drill that makes a 75% depth. Most tap charts show both. I also use fine thread when I can in Aluminum.

That's the key for threads in aluminum. Just make sure you use plenty of lube, and clean the hole lots.

Karosene works good too.

I am with Gordon, coarse threads in aluminum. I have never seen fine threads in the aluminum parts I have made. At least engineers understand that:flipoff2:

Worst part I had to make-a 7"(roughly) O.D. and 6.5'(roughly) I.D. bearing adapter out of aluminum. Bearings are usually +/- .0004. Aluminum expands at .0006 per 1" per 100 degrees F. 7 X .0006 = .0042. .0042/ 10 =.00042 per 10 degrees F there goes the tolerance!:flipoff2:
Engineers:rolleyes: It's enough to make you quit machining and go back to school!

Originally posted by cmk
Tap Magic makes a formula specifically for aluminum. Whether or not it helps, I can't say for sure. But I haven't had any problems when I've used it.

cmk

Just don't use aluminum lube on steel, trust me :rolleyes:

Originally posted by Sloan
Is there anything special that needs to be done or is it the same process as threading steel?:D

Sounds like a job for Rumplestiltskin. :D

Originally posted by r77toy
Just don't use aluminum lube on steel, trust me :rolleyes:

How do you think I found out that I bought Aluminum Tap Magic by mistake. :D

cmk

are you going to put a helicoil in it too?

If the threads into just the aluminum strips out the heli coil was going to be my next item to try.

Man, for the life of me, I could not figure out why you wanted to put "thread" into aluminum.

I'm so dumb LOL :rolleyes:

Oh I do have a tip though...be sure to push down on the tap as you run it in to help keep the threads from getting shaved down any more than they have to be

Originally posted by Gordon


Standard engineering practice is coarse thread in aluminum. this is strongest with most aluminum alloys.

Huh, I wonder why most automotive parts use fine or extra fine threads in their aluminum and magnesium parts? The alloys they use maybe? :confused:

Like others have mentioned, use a form tap if they are available. They work fairly well as a bottom tap also.

Countersink the hole so there is a good lead-in for the tap.

Also, use a pilot hole to align the tap so it is parallel to the hole.

Just my .02 :D

I do a lot of hand tapping in AL and have good luck with two flute taps. Slows the chips down from taking out the threads. Not had good luck with fine threads though. Too easy to cross thread the fastener.

As was stated above, Tap Magic for AL is great. You can test the difference pretty easily. Do a couple of tapping operations without it and then a couple with. The difference is night and day.

when hand tapping anything, go one rotation forward, half rotation backward. you'll feel the tap cut the chip. this makes th chips smaller and helps keep them from tearing up the new threads.

if i am making an aluminum structural part (not a bracket), i put a heli-coil in it. i also put helicoils in my bellhousings, even if the threads are good. doing it on the workbench is easier that under the jeep...

any kind of oil should be fine for hand tapping aluminum. yes, you can spend half a day looking for AL tap magic...but that half empty quart of old tranny fluid will work just fine.

matt
Engineer,machinist, welder, fabricator...

Originally posted by jeepnmatt
when hand tapping anything, go one rotation forward, half rotation backward. you'll feel the tap cut the chip. this makes th chips smaller and helps keep them from tearing up the new threads.

if i am making an aluminum structural part (not a bracket), i put a heli-coil in it. i also put helicoils in my bellhousings, even if the threads are good. doing it on the workbench is easier that under the jeep...

any kind of oil should be fine for hand tapping aluminum. yes, you can spend half a day looking for AL tap magic...but that half empty quart of old tranny fluid will work just fine.


A form tap doesn't produce chips, as it "rolls" the threads, instead of cutting them. Structurally, the heli-coil shouldn't be any stronger than a form-tapped hole.


I can understand using a steel heli-coil for a hole a person plans on being able to remove the bolt easily. The heli-coil basically oxidizes with the AL, keeping it in place, which is a good thing.

Otherwise, a steel bolt corrodes to AL threads, making it difficult to remove after time. Another option is using a Stainless Steel bolt, and not using heli-coils.

Originally posted by zags


Huh, I wonder why most automotive parts use fine or extra fine threads in their aluminum and magnesium parts? The alloys they use maybe? :confused:

They don't at least not many automotive parts I have worked with. In certain aerospace applications they do use fine thread into aluminum lithium alloys, but that is the only place I remember seeing fine threads into aluminum in a well thought out design.

Why would a stainless bolt in an aluminum thread corrode the aluminum less than a plain carbon steel bolt? Since ss is more noble than both carbon steel and aluminum switching to a stainless bolt would increase the corrosion potential. in fact a zinc plated carbon steel bolt would provide some galvanic protection to the aluminum.

Originally posted by Gordon

Why would a stainless bolt in an aluminum thread corrode the aluminum less than a plain carbon steel bolt? Since ss is more noble than both carbon steel and aluminum switching to a stainless bolt would increase the corrosion potential. in fact a zinc plated carbon steel bolt would provide some galvanic protection to the aluminum.

I may be mistaken on that. I really don't have any hard (book) evidence of S.S. corroding less than steel against AL, only some experience, and a little metallurgy background.

- S.S. itself corrodes far less that steel.

- Zinc Chromate finishes wear off over time. The body bolts on my rig are a good example of that.

- I have quite a few Aluminum solid heli-coils in my 'glass-bodied Bronco. The s.s. bolts come out far easier than standard metal bolts when I do maintenance and repair.

SS steel ahh doesnt corode less than other steel. it has less carbon in it and there for has a lower potentioal for oxidation. The corosion you have with SS and alluminum is galvanetic and is due to the dis-similar metals in contact with each other. You could use any bolt combo if you use a product called no-lox it is a corosion preventer between dis-similar metals and can be purchased at electrical supplies stores.

I've had really good luck with using a helicoil. Just a little insurance against stripping the hole.

Just my $0.02

Originally posted by Gordon


They don't at least not many automotive parts I have worked with.



Must not own a Toyota huh? :)