I know its not the dun thing but I need to put a nice edge in a bit of 3 mill ally and its a rather awkward shape. Anyone know if they do router bits that will handle metal?, suppose the router goes too fast normally but seeings its ally which isn't that hard. Come to that a few sacrificed router bits wouldn't be a hardship!....
Ally machines almost like wood, with wood tools. At wood speeds too..
We used to use a normal pull saw to cut aluminium heatsink extrusion..
Expect to end up with a gash router bit tho.
Akward shape,how do you mean? a dremmel or clone(Aldi) is a must tool to have for alloy particulary if you have its stand so you can pass the ally through rather than pass the drill over the ally.
With traditional brasswork, a hand plane or block plane is used to plane the edge of the brass sheet up to the wood - with no harm done to the plane.
The same technique *may* work with aluminium.
As with any soft metal work, be careful of overheating and melting the metal. Unlike wood, you don't get charring and smoke as a warning :-) In the case of Aluminium, it will most likely only produce a poor finish, since it isn't strong enough to cause a friction weld problem. Copper is another matter, since it can braze itself onto the cutter... BTDTGTTS
normally
It'll probably work, but the danger is that the aluminium will stick itself to the router. Aluminium is a very reactive metal, but rapidly forms an oxide layer that stops the activity. As you machine it, you are constantly exposing fresh reactive aluminium which will stick and block the flutes of the cutter. Ordinary WD40 used liberally as a cutting fluid help enormously.
AWEM
In article , JohnW writes
So what would be the recommended bits for this then, and method to get a good finish..Suppose its off to Mackays with it otherwise!..
I believe you can get hold of a new fangled device in various shapes that has a cutting surface embedded into it. By placing it on the metal and rubbing it backwards and forwards you can actually remove and fashion solid metal by hand!!!!
A truly amazing invention, ISTR its called a foyle or fowl or fiyal or something like that.
Basically, there are two types of aluminium.
The first type (for e.g. L65) bends quite easily and is a soft metal that will invariably stick itself to the leading edge of the router cutter quite quickly.
The second type of aluminium (for e.g. L72/L73) is the brittle one that will not bend, but crack half way through bending. This type lends itself to shaping by using a router cutter, but can still stick to the cutter of you try to cut too much, or too fast.
IIRC L65 is bendable and weldable, but L72 and L73 have to be heat treated to get complex shapes out of them. Depending on the heat treatment that they get, will depend on whether they revert back to L72/L73 or stay soft and malleable.
HTH
Dave
In article , Icky Thwacket writes
Yeabut these need to be straight lines;)
Trend do bits for machining non ferrous metals. Never tried them but.
Peter
No, at least not by the usual retail routes.
You don't want to machine metal with the tool angles on typical woodworking tools, including aluminium. You can find alternative tooling, but it's still not a good idea.
Tool forces are higher for maching metal, so rigidity and vibration become problems. It's not really practial for a hand-held router.
Aluminium will suffer from "galling" (welding to the tooling) if you work it too fast. You might not get a router to run slowly enough to avoid this.
Although you can rout aluminium, it's not a simple one-off setup. Use metalworking tools instead.
In article , tony sayer writes
Just to let the contents herein know..
I've tried this on a lump of the said ally and even using an old, not that sharp wood bit, around 15 mm diameter the results are excellent:)
Speed is quite important as well as taking light slow cuts, faster speeds result in a "torn" edge the slower ones give a much better finish. I tried with and without lube, Oil was the only thing to hand and it didn't make that much difference either way.
Thanks to all who replied..
One rather happy bunny here:))
In the past working ali (on a real lathe) setting the tool a fraction of a mm too far in caused the tool to be thrown, yet you did yours with a hand held router. Wheres the difference?
NT
Continuous working pressure verses fast but intermittent working action
Dunno!, It produced a very fine sort of chipping swarf but a very neat finish:)
Actually wood and ally have fairly similar requirements for a cutting tool. They both need fairly high speed and tools with coarse open teeth or clogging will result so in fact proper carbide or HSS burrs for ally aren't that disimilar to routing tools. I'm therefore not surprised you got a good result. 15mm is a similar size to the HSS and carbide burrs I use for porting cylinder heads and a good speed for those would be 5k to 10k rpm (The carbide ones can cope with higher speed than the HSS ones obviously). Up to a point you remove stock faster with higher speed but if you go too fast the tool stops cutting properly as the heat generated starts to clog the teeth with swarf and the burr skips off the workpiece rather than digging in. Slower speeds will also work fine but just take longer.
If you google for carbide porting burrs you'll see that those for cast iron and steel have fine teeth or even a crosshatched tooth pattern for roughing out and those for aluminium have a very open tooth pattern, maybe 1/4 the number of flutes in a given diameter. Every now and then I have to machine some wood, to make a drill bit stand or a fixture for holding a cylinder head and I find that an open toothed aluminium porting burr works just fine rather than buying a routing tool for a one off job.
Finally, oil isn't really the thing for machining aluminium especially as what you probably had to hand was lubricating oil rather than cutting oil. The two are very disimilar. One is designed to lubricate which is actually the last thing you want when trying to get a cutting tool to dig into metal and the other, although called oil, is designed to cool and prevent flute clogging without actually lubricating. The thing to use is paraffin (kerosene) or at a pinch anything similarly thin such as diesel or heating oil or WD40. Paraffin has an almost magical effect on the performance of a porting burr. The flutes cease to clog up and the stock removal rate increases dramatically. It does of course mean that the swarf sticks to everything so you can't see what you're doing so well. I use it for roughing and then go back to dry cutting when working towards the final port shape.
We gave up with the paraffin years ago when we had the gas laid on;!..
I'll trey that as I now have some more to do..
Thanks for the advice...
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