cutting threads in aluminum?

We need a liver????

 

the last set of Taps I bought are the 3 flute spiral type. These suckers Tap aluminum beautifully! I also use the half turn method. and Tap Magic.

I actually ran a machine that ran taps for about 12 hours. I was fascinated the whole time. it was self reversing. I bet I threaded about 1,400 1/4- 20 holes, blind ones at that- and every one was perfect.

I still want one of those machines. they were just too cool to watch work.

 

Tapping machines are a wonderful thing aren't they? The reason I mentioned thread forming taps is that there is no chips to worry about. It does not cut threads it just displaces the metal.
Fitysix

 

Im with Fat Hack & Dyce, I use WD-40 when tapping & machining aluminum. Fat Hack also gave good advice for making a tap guide for holding the tap straight while tapping hole's. The only other advice I have that I haven't read here is use a tapered tap, a chip breaker is good even for hand tapping, if you are tapping a blind hole, you can go back with a bottom tap if necessary. Like said before, use good taps, Iv'e seen some bargain taps that won't cut shit, good luck.

 

Kerosene.Works well.Don't go crazy and flood the joint,and no,it ain't THAT flamable.Damn near takes a torch to get it going.

 

I do them with a regular tap. Just go slow and easy. Lots of oil helps. Never had a problem.

 

I've tapped a lot of aluminum and have found isopropol alcohol to be the best lube for aluminum.

 

i run taps in aluminum on a lathe and bridgeport mills i use the valcool stuff the shop buys looks like blue dish wash soap and a little water and it turns white
stuff works great and i do production work so i can't never go fast enough
use a shiny steel one though black oxide taps gall and the part goes by by

 

Kerosene works really well too.


Jerome

 

Hand Taps suck.Bottoming taps are sometimes useful in blind holes.

I use Spiral Point Machine Taps for 99% of anything I tap,by hand or machine.

Spiral Taps are OK for production tapping of blind holes,but are definitely not as strong as a straight flute tap.

 

ALWAYS.

The OD on the chamfer should be just
slightly larger than the diameter of the tap.

 

If your tap has a build up of aluminium on it already ( from the galled threads ), run it through a piece of steel to clean off the build up. Built up edge will fuck with any cutting tool.

 

Bee's wax is an old standby for tapping aluminum. I use it all the time. It's easy to find ; for instance, lip balm made from bee's wax can be bought at drug stores.

 

The most importen thing is drilling the right size hole with aluminum or steel !Rusty bolts is i think the only one who said anything about this .I think theres a chart that tells you the drill sizes when tapping aluminum and its metric but im not 100 on that

 

By the way, Tap Magic doesn't have 111 Trichloroethane in it anymore like it did in the old days. They banned the production of that stuff about ten years ago because it was an "ozone depleting chemical". I have a can of Tap Magic on my desk here that's several years old, and it says "New & Improved" and "Now without 111 Trichloroethane". It claims it's okay for aluminum. Most of the time I use it for tapping steel or stainless steel though. I know a lot of guys in the shop like to use kerosene or some green cutting oil for tapping aluminum.

 

we use form taps or xpress taps in aluminum the hole is drilled bigger and the threads are formed not cut the threads are stronger also

 

Use the old tap magic that smells like cinnamin,you know the shit the kids put on toast in the morning. I have a old can and this shit does the trick>>>>.

 

What is an "aluminum scale" ?

None of my machine shop text books mention this.

 

Its a chart with drill sizes for taps i have it for steel. I think it may be metric drill bits for Some Aluminum .I guess i should have explained better . I did not mean scale i meant chart sorry dont shoot me there . unk ian

 

Tap Drill Chart

 

standerard drill sizes / millermeter sizes have different tolerances in there (drilled holes) meaning somtimes using a metic bit has a stronger tolerance then the standand hole used on steel .Leaves more meat with the metric drill I think this is why he pulled the threads out when tapping he used the wrong size or standard drill on soft metal . .I got this info from an engeneer i worked with building machinery years ago and i just looked it up to confirm With aluminum you want 75 % thread or close . Threse math involved

 

Use spiral point machine taps, two flute, grind the point off one if you need to get near the bottom of a blind hole.
Proper tap drill is essential. Use the tap drill chart, you'll remember the most common sizes quickly. Same sizes for steel and aluminum. You'll need a set of number drills and letter drills. They'll work for metric threads too, you don't absolutely need metric drills.
For aluminum, use a very thin lube, like WD40 or kerosene. Varsol also works. A thicker lube that thins when it gets hot is better for steel.
Chamfer the hole, make sure the tool is sharp. I like to use a small magnifier (6X works) to look closely at the cutting edge. If your tap gets dull or chipped, throw it out before you trash a workpiece with it. Anything you can do (drill press, guide block) to ensure alignment is cheap insurance.
Thread rolling taps make stronger threads in soft materials like aluminum and zinc, tough to do well by hand. And yeah, larger tap drill size.
And buy good quality taps from an industrial supplier, not the hardware store or flea market krap.

 

Its not always the same size for steel as aluminum i just spent an two hours reading about hole tolerences and metal strangth and thickness .

 

Moly Dee for me. I use it every day.

 

Ive never had a problem and I have used several cutting oils .I have nice taps but I always tap coarse threads in aluminum its like wood.

 

We were taught to use 70-75% for most jobs.
Lower % were acceptable for Stainless and Tool Steels.

I've got a chart from Cleveland,with at least 3 different % for every tap size.

 

When in dought I grab my good old..well 28th edition now machinist book...hasnt failed me yet..
Most skills are learned via mistakes, trail and error, or in my case beat into my head.. ** a one armed machinist ( long story)** Anyway, Everyone has different process, are they wrong, well if they produce the required result..must be right. Do some ideas work better, thats depends on the user. To me most things like this seem like common sense, to others WTF. Live and learn

 

I like to use a Gun Tap whenever I can. For aluminum, brass, copper material that tends to "Grab" I grind a more Positive Cutting Rake to the cutting flutes so they look like a wave crashing. I learned this from an older Experienced Tool Maker. I was amazed at the results.

 

Crisco and min. spirits mix with a new tap.

 

+1. It's the best thing I've found, or it's first cousin kerosene works well too.

Bob