[tikka308]

Hey Folks,

I wanted to share a great experience last night. I was facing a piece of 0.75" square bar stock and wanted to get the best finish possible. I used a 4-flute 3/8" HSS End Mill at 5000 RPM, 7IPM, 0.030" DOC and was incredibly pleased with how smooth the surface turned out. While you could clearly see the toothpath, the part was very smooth.

I then used two different levels of 3M Scotchbrite and, after about 5 minutes, had a silky smooth finish completely devoid of any toolpaths. I think it's a great testament to how accurate & pleasant TAIG's can be when working with aluminum.

I've posted some more details and a youtube video of the part on my blog - check it out! http://www.nyccnc.com/Herbie/HERBIES..._Aluminum.html

Cheers.

[Gumby]

It's too bad taig can't use 1/2" end mills. I have these 6 flute end mills that leave a beautiful surface finish. I almost don't even have to polish the part after machining. Have you tried using a fly cutter?

[tikka308]

I have tried fly cutting and have definitely had good results, but can only remove a VERY small amount of materials - say 0.001". I need to remove about 0.030" for this part, so would prefer to do so without a tool change (i.e. an EM and then fly cut) since I have to make quite a few of these.

What kind of mill are you using with you 1/2"

[CROSSHATCH]

Tikka- When I cut my pieces I always then polish them with very fine grit. I don't polish what I cut, a 3mm thick piece is profiled and the top and bottom get sanded. It makes the aluminum look very nice. The Taig really does make great cuts in Al.

P.S. check the thread for the enclosure, think you will like it.


-Jason

[tikka308]

Speeds - just saw the new enclosure; checking it out now.

When you say "very fine grit", are you talking about sand paper? I didn't follow your comment re: 3mm piece...

[CROSSHATCH]

Right, I profile a piece that is already 3mm in thickness. But the aluminum I cut it from is rather dirty and scratched. So I use very very find sand paper and polish the top. It actually has no relevance too your topic because you polish away the mill marks. But I know what you mean, I do that sometimes too!

-Jason

[tikka308]

Jason - now I follow. What grit sandpaper do you use? What polish do you use after sanding?

[pzzamakr1980]

Tikka, you were talking about how to get the polisher and not have a circular motion. Tilt the head at a decent angle, use an polishing adaptor they sell for drills, chuck it, and just use the edge of it. I put a few dabs or superglue to hold the pads on, and just move the workpiece back and forth under the edge. I use this method with a homemade arbor, which was made on a lathe with scrap,to great effect. I have high density foam that I made into barrel shaped cutouts that go around the arbor, and with red and white turtle wax I can get a beautiful mirror finish on aluminum in a very short time. You can do the same with scotch brite pads, just cut in strips and glue together, then wrap them around something the same size as the arbor, and that way they are a bit cushy and conform better.

[tikka308]

Pzzamark - interesting idea. If I follow you correctly, you're basically putting a large-diameter cylinder in drill (for lack of a better example, think of a carousel wheel) and using the side? Obviously, although it's spinning, it's really a linear pattern on the side-contact point... great idea! Do you have a picture of your set up?

I have also been looking for a good polish for aluminum to get a mirror finish after I've scotch-brited everything. You use Red & White turtle wax? Is this it? http://www.amazon.com/Turtle-Wax-T37...9002036&sr=1-3

[pzzamakr1980]

Nope its the paste wax stuff that comes in a big shoe polish looking container. Im sorry, neither of them are actually wax, the red stuff is turtle wax rubbing compound, and the white stuff is polishing compound. Before I use those I use your regular green scotchbrite pads or 1500 grit sandpaper saturated with oil. Then I do the two turtle waxs and its a mirror finish. Actually, if you are not too anal, you can use 1500 than 2000+ sandpaper sprayed liberally with wd40 for a near mirror finish.

Yes, its basically just as you describe. By not using the whole round arbor and just using the edge, prevents swirls pretty well, and the finish doesnt look crappy. I will either move the piece back and forth by hand under the polisher, or use my mill to rapid back and forth. It works great, but I dont have any handy pictures.

[pzzamakr1980]

One last thing, if you want a polish that is chrome like, and looks like a car paint job, finish it off with a good auto wax and a polishing bonnet. I love meguires carnuba paste wax. I light it on fire, drip it on the part, and polish away. It takes some time but it is freaking amazing. On any part that can corrode, it also helps prevent the corrosion from happening in the first place. I coat my table before I mill with a good wax. Its not oily and it wont just wash away.

[tikka308]

Pzzamakr - where do you pick up your turtle wax? I have to order most of my stuff online due to location and would love to get your help with the specifics on the red wax rubbing compounding and the white polishing compound. It looks like this is the red rubbing: http://www.turtlewax.com/main.taf?p=2,1,4,13 and this is the white polishing: http://www.turtlewax.com/main.taf?p=2,1,4,14 ?

Also - don't laugh - but where do you buy 1500 and 2000 grit sandpaper? The highest I see on Enco is 1200...

[Stepper Monkey]

Any good jewelers supply catalog like Rio Grande or Otto Frei will have sandpaper from 600 up to 10,000+ grit or so.
More importantly, since jewelers specialize in getting inanely fine mirror finishes on all manner of metal and stone surfaces, I think you will all find entirely new worlds of metal finishing techniques and tools you never knew existed. It isn't just for tiny stuff, remember these guys stock things for work on bronze statues bigger than your car, too. Even if you only discover that Scotchbrite pads come as giant discs that replace bench and angle grinder wheels, you will have done yourself a big favor. I can't begin to count the time and effort some of the jewelers catalog stuff has saved me.

[pzzamakr1980]

Any auto store would have the turtle wax and the paper. Lowes or Home Depot might have the stuff as well, but I doubt it. I dont remember if pep boys is in the northeast, but if it is, they have all of it. Generally, grit that high is for automotive paint work, so enco and its ilk probably wouldnt carry it. Just make sure when you use high number grits u either soak em in water or oil, because the stuff builds up quick, making the paper useless.

[pzzamakr1980]

And stepper is right, although I dont find it necessary to go any higher than 2000 grit and then using the turtlewax stuff. Add a good carnuba auto wax and the finish will be beautiful. Although do remember, good finishes take time, so always try to get the best finish during the milling/turning process. It will then take much less time to get those mirror perfect finishes.

From what I can see of your pictures, the surface finish you get looks good, but instead of using the endmill for the whole part, use it until your .004 out, then use your flycutter for the rest. It will save you a great deal of time. And make sure if you decide to use a flycutter that the machine is trammed properly. An improperly trammed machine will make a fly cutter finish and tolerances crap.

[Gumby]

What kind of mill are you using with you 1/2"

Tormach PCNC

[cadmonkey]

Just to toss in my .02 - I've used the "Surface Prep" discs that HF sells that twist into a 2" backer and different auto parts stock them as well medium and fine are the best - the coarse is really aggressive and saved for large parts from extrusion that I don't want to flycut. Liberally apply cutting oil (I use Rustlick WS5050) and the finish is smoother than a baby's bottom, a light pass with some 2000grit autobody paper and the same oil on a normal sanding block or foam if contoured and it's practically mirror finish. I can do that from the normal endmill cut.

[Anokiernan]

As far as giving machined pieces a nice smooth surface, nothing beats a buffing setup for speed and controllability. These parts were machined on a bridgeport out of 6061 T6 then polished with tripoli then white rouge. All in all, the finishing of the machined parts took maybe a minute and a half each part with very little physical exertion.


The same polishing process was used on these wheels after turning the lips on a lathe.


I've noticed you've invested a significant amount of money in your equipment. If you have a need to control your surface finish often, I would highly suggest you invest in a bench buffer.

[tikka308]

Stepper Monkey - THANK YOU! I just browsed a lot of the catalog PDF's for Otto Frei & Rio. What - what a great asset. Cannot wait to play.

Pzza, CadMoney & Gumby - thanks for chiming in! I'm going to research these ideas and am looking forward to getting an even better finish!

[tikka308]

Anokiernan - thanks for the info. When you say a "bench buffer" are you referring to a benchtop grinder but with buffing wheels?

Those parts look great. I'm not familiar with tripoli or white rouge, but I see tripoli here http://www.dadsrockshop.com/compounds_acc.html and white rouge here http://www.eastwoodco.com/jump.jsp?i...emType=PRODUCT Am I on the right track?