I'm trying to make a couple of parts for my car using some 6061 common everyday aluminum. Since I don't have a Bridgeport or any other milling machine have to chop/clip/cut/saw/grind/file to a close dimension. In this case I've used a hole saw and of course have left the usual 'spurs' that have to be ground off. Now, being of the 'mechanical' generation and want to do it the easy way, decided to crank up the ol' air compressor, dig out a die grinder and my batch of carbide burs - and of course they immediately load up with aluminum, making them useless until I dig the teeth clean. Now - I know that I've used burs before on aluminum, and successfully and even the same ones without loading them up. Possibly I had a different grade of aluminum. I think I now have about 8 burs that need cleaning. I tried slowing the grinder, it's as bad or worse. Faster - I'm there, it wont go faster and loaded up. Yes, McMaster Carr show some non loading burs, but I want to do my job now, not Tuesday or Wednesday. Any ideas? Besides a mill bastard file?? :sweat:
07-25-2009 04:45 PM
You can try a little beeswax on them, but even that is going to be iffy.
40 and 60 grit flapwheels don't do to bad.
07-25-2009 04:46 PM
A mill file will load up also. In the shop, we flood the part with WD40 or get a common toilet bowl ring (bees wax etc). Load the cutters or stone and start cutting.
07-25-2009 04:49 PM
07-25-2009 06:21 PM
Best luck I have had with them is the beeswax, not a perfect solution but it helps. Just plain bearing grease also works fairly well, again not a perfect solution since the burrs will still load up but they will clean a lot easier.
07-25-2009 08:44 PM
Yep beeswax is about the best solution short of aluminum cutting fluid.
07-25-2009 09:16 PM
Also make sure you are using the correct burr for aluminum, instead of one for steel or cast iron.
4 Jaw Chuck
07-25-2009 11:35 PM
Varsol is the best, keep dipping the part and burr in it to keep the AL from sticking. Also don't press so hard on the burr and take small bites, if your turning so high an rpm that the Varsol smokes when you dip it thats too fast.
07-26-2009 12:23 AM
Again as CNC says, the carbide burr made for alum. has wider or a larger gap between teeth, won't load up as fast....and is easier to clean out with a stiff wire brush.
07-26-2009 06:37 AM
Thanks all -
I had an idea last night and tried it and it actually worked. I was rooting through one of my tool drawers and found a common carbide wood router bit that had a chip so was just dumped. Since it is only a two flute cutter, figured that it had to work and it did. That was a .25 bit and since the aluminum didn't do any more damage, I then tried a well used .75 and that worked even better. Then a good 1.0 was tried and that works best of all.
What I found was that the .25 dug in very easily leaving what looks like chatter marks, with the 1.0 making a nice smooth even surface.
From what I can see is that these router bits don't wear quickly, can leave an acceptable surface, are cheaper then the regular burs, have many profiles, and can be found in almost any local hardware or big box store. My guess is that they could be used with a router table as well if you were slow and c-a-r-e-f-u-l and used a .500 shank cutter. One reason for their survival appears that the die grinder runs at about 12,000+/- rpm while my big Porter Cable plunge router turns at 27,500+/- and they remain fairly cool.
It turned out to be an interesting experiment - that worked :D
07-26-2009 08:11 AM
They work but I found, after trying the same thing, that they tend to snag and kick back much worse than the regular burr, I even ruined a Dewalt electric die grinder with one when it bent the shaft. Be VERY careful with that bit!