Routing aluminum

---------------------------------------------------- Watch out for AL chips getting into the router. Been there Donald Warner

Don't let the facts interfere with your prejudices

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If you're routing by hand, it could get interesting. I suppose there is no need to get into the safety of a router, especially when routing metals. I assume you're likely well versed on it.

There is but one problem with using an end mill for routing that I can see, and that is if your router accepts only 1/4" shanks, you'll be hard pressed to find any end mills to use. End mills come in either 3/16", 3/8", or

1/2" shanks. They do not come with 1/4" shanks, at least not here in the States. While I've never sharpened any router bits, I can't help but believe that they are, in a sense, nothing more than end mills. Both of them rely on cutting on the periphery. Clearances for cutters for machining on wood would be similar to those for machining aluminum, so they should work fine. The one caution worthy of mention is to not climb cut, always conventional cut so the cutter doesn't "drive".

I can't imagine routing with carbide cutters wouldn't leave a reasonable surface providing you lubricate the cut somewhat. What's most likely happening is a little aluminum is welding to the router bit and is streaking the machined surface. Try a tiny bit of kerosene on the cut, at least for the finish pass, and see if that improves the finish. If it does, you'd face the same problems with an end mill, so changing to one isn't likely to solve the problem. Lack of rigidity may be the problem with the finish. Hard to say without seeing the cut.

Harold

??? I've got a drawer full of them. Did a quick search at J&L and found three offers:

On the other hand, a router bit should work just as well. The problem is almost cetainly AL welding to the bit causing a bad finish. Try the kerosene lube.

Karl

If it's a variable speed router, maybe try turning down the RPM's a little bit.... sounds like the aluminum is welding itself to the cutting edge.... Ken.

I have trim routers mounted at an included 60 degree angle in a mirrored fashion near the rim of a powered Bridgeport brand rotary table, taking a .005 trimming/deburring dry cut on the ends of small copper rods as the parts pass by at 550 parts per hour. Right ahead of the routers is a double angle milling cutter set, removing most of the material. I use 1/4" diameter/shank carbide end mills, and the routers sometimes run for 10 hours straight. The built in cooling fans and my shields seem to keep them relatively clear of chips, but I'll lose one about every six months or so, when a chip hits the wrong spot. The bearings or armatures usually wear out first in general, though. Woodworking routers have their uses in metalworking, for sure.

RJ

That is strange Harold. I've been using a 1/4 milling cutter in my router for years. Solid carbide, don't remember what source it was from but I'm sure I've seen them from Enco and Wholesale Tool. I also have a 1/2 in one but it is

4 flute and so loads up pretty easily. ...lew...

I don't rout aluminum (IMHO the router speed is a bit high for that), but I have bought quite a few 1/4" shank solid carbide endmills from MSC, and then used them to rout wood (because when MSC has a sale, they are cheaper than woodworking suppliers, and the end mills seem to work just fine in wood). So I can't imagine why you think such things don't exist, Harold. A VS router turned down low might do, and I know of people who do route aluminum that way.

Most woodworking bits are 1/4" or 1/2" shank, but I can also get a 3/8" collet for my router, which probably is aimed at common end-mill use. And if you're milling something where 10,000 rpm makes sense (wood, plastic, wax) there should be no problem with that. Not owning a VS router, I'm not really sure how low the VS ones go.

snipped-for-privacy@aol.com (Charlie Wilson) wrote in news: snipped-for-privacy@mb-m07.aol.com:

The surface speed is too high for carbide in aluminum at router speeds. The aluminum is melting and building up on the cutting edge. Give one of these a try:

PCD tipped should last forever, and is just as effective in wood as in aluminum. I would provide some lubrication, my preference for your application would be a water based coolant mist. You can get these systems in 1 gal portable units that run off of compressed air. The PCD will not build up aluminum, and will leave a very clean finish. You can also, depending on your set-up, work very fast.

As someone who has routed lots of aluminum I can tell you that a very good finish is possible with carbide routing cutters. What happens when routing is that the router bit will tend to get a build up of chips on the cutting edge and then these chips are pressed back into the aluminum. So, using cutting oil will prevent this. Even kerosene will work. Some people use WD40. An end mill will tend to pull itself out of the router unless you buy one with a reverse helix which will push the cutter into the router. It may also cause the router to jump around. Even an endmill will push the chips back into the work if used without cutting oil. This is because of the direction of travel when routing. If you could use the router in the direction which self feeds (CLIMB CUTTING) then this would be less of a problem. But if you try that the router will get away from you. The carbide router bits generally do not have the edge as smooth as a carbide endmill. So you may see paralell lines from the cutting edge on the work. If you use a diamond hone on the edges they can be smoothed to get a better finish. Since the flutes on a router bit are straight it neither pulls itself out of the router or pushes itself back in. I sometimes use router bits in a milling machine to chamfer aluminum and brass parts. I use a setup where I can pass, by hand, the part pass the bit. I have done this on stainless too but it's hard to get a good chamfer if it's very big. Eric R Snow, E T Precision Machine

Two thoughts...

1. HSS is sharper than carbide, though it won't last as long without sharpening.
2. A router speed control is cheap. I bought mine a Harbor Freight for .95 on sale.

or

got the yellow one, and it works fine.

Ron Thompson On the Beautiful Florida Space Coast, right beside the Kennedy Space Center, USA

The ultimate result of shielding men from the effects of folly is to fill the world with fools.

--Herbert Spencer, English Philosopher (1820-1903)

Damn, there goes my tunnel vision again. Sorry folks, my mind was on HSS cutters, not carbide. Yes, I acknowledge, there are solid carbide end mills in 1/4" shanks. In fact, I have some of them in my collection of end mills.

Seems I just can't help but recall the good ol' days when that was not true.

I stand corrected!

Harold

I don't know that I'd want to use a router for the entire job, especially in 3/16" plate, but roughing the opening (to within 1/16") and finishing with a router works great. I use a Porter Cable 690VS and crank the speed all the way down, which works much better than my older 690 fixed speed unit ever did.

1/2" solid carbide bits seem to work much better than standard wood working bits. In the days before those were available I'd use standard 4 flute 1/2" endmills. The carbide milling cutters will hold up to this better than wood working bits because the carbide is less brittle.