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.
The same technique *may* work with aluminium.
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.
>Anyone know if they do router bits that will handle metal?,
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
Although you can rout aluminium, it's not a simple one-off setup. Use
metalworking tools instead.
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?
Continuous working pressure verses fast but intermittent working
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.
Dave Baker - Puma Race Engines
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...