Thread: Routing in aluminium

I thought you used a milling machine to work with aluminium, well fitter and turners do.

Boat builders use standard routers with standard TCT bits to cut aluminium sheet up to around 3mm. Tends to go through bits quicker than in wood of course, but works well.

Peter:
I'd suggest checking with Festo and getting their recommendation for your particular router.

I used a 1/8" solid carbide spiral bit with a circle-cutting jig to rout a stepped hole for insert plates in a 6 mm thick aluminium plate in my router table. It worked well and did not damage the bit. I have not tried using larger bits. I used a relatively slow speed, about 15,000 rpm. With any larger bit, I would use the slowest possible speed.

Incidentally, I would recommend 6 mm aluminium as a material for a router table plate.

i have used aluminium edge strips of about 3mm for some furniture i made recently and simply used a normal flush cutting bit at a slow speed. didnt think twice about it and worked a treat.

Use Tools (bits) like the
Cabi-Tools Tunsten Carbide
COMBINATION FLUSH TRIMMING & DRILLING SPIRAL DOWNCUT bit
(This bit is used extensively to drill and trim sheet aluminium. )

Do NOT use the Std woodworking Router bits to cut aluminium.

Also,
Aluminium cutting/routing usually needs lubricant and the most common lubricant used for for cutting aluminium is the extremely flamable "Methanol" - surprise? But with your homemade table, the use of METHANOL lubricant is not feasible. The under table router has carbon brushes will create sparks and cause fire if methanol drips into the motor.

So do slow down the routing speed as you must probably cut without using methanol lubricant.

My experience with cutting alumiunium is mainly with CNC routers where router is on-top of aluminium

(I consult, sell and support CNC Routers for wood and also various metal CNC machines).

Wow. Thanx for the great response and different opinions. I'll . On the subject of an aluminium router plate for the table, can you do a homemade job on a piece of alu, or does it require high accuracy?
It would give me 13mm I don't have now (I'm using 19mm MDF for the top )
Or is that a new thread?
Many thanx, Peter

Peter,
Yes you can make your own router table plate from 6 mm aluminium, as I did. I had the aluminium supplier cut the 200 mm x 300 mm plate with a guillotine cutter, and then rounded the corners with a file to fit the rounded corners of the stepped hole that I had template-routed in my router table top.

To rout the 100 mm diameter stepped hole for the 4 mm thick steel insert plates, I used a shop-made 9 mm thick polycarbonate circle-cutting jig bolted to the router base. I drilled a 3 mm hole at the intersection of the diagonals of the aluminium plate and inserted a cotter pin as a pivot for the jig.

YES you can rout aluminoum with a normal router and normal carbide bits.
but it needs some care and there are limitations.
I myself and several of my mates rout aluminium for various reasons in various forms.

there was a post on similar matters a bout a week ago from memory.

firtsly see if there is another way.

then.
Take exreem care. aluminium flies & grabs much worse than wood.
Wear full face protection & good ear protection

a lubricant is very helpfull & advisable but you can do without

you will probably have bit cloging problems with bits under 1/2"

There is a real limit to how thick the material to be cut can be.
I have only ever cut 2mm or so one friend routienely routs 4mm to make theatrical swords.

make sure the job is very well secured and preferably use a heavy machine.

Forget any idea of free hand work.

Just as some mushrooms are edible, it is correct to say that some router bits for wood can be used to route aluminium. I totally agree with that. "Dead mushroom eaters cannot post information on a bulletin board anymore so it will be irresponsible to say that all bits for wood can be used to route aluminium.

Not all bits for wood are suitable for aluminium. But some can be used. And FYI, aluminium is the only common metal that has been cut or routed with the router (not brass or iron or steel !!!).

There are bits specially designed for routing aluminium (some are HSS others Carbide or TCT). These are usually small in diameter and only one or at most 2 cutter flutes. Just ask why are they designed that way????

Lubricant/coolant (e.g. methanol) is strongly recommended. If without lubricant/coolant a lower speed can help disipate heat generated by friction.

The router is best on top so that lubricant can be dripped automatically for production routing of aluminium. If cutting only, you may clamp the alumiunium stably with expanded styrofoam (packing material) between the aluminium sheet and the table.

Suitable routers for aluminium are those more powerful ones with variable speed control.

Reuelt has some good tips.

I have used my makita trimmer with tct straight cutters to "machine" aluminium and acrylic back when i was shopfitting.

i have even used special die grinder bits that suit the 6mm chuck
on my trimmer.

I know for a fact the boys at austal ships use TCT blades when building their boats out of ali.

G

One mate had an interesting situation.

He was building a heavy cable packer with "special reinforcement" and was at the point of routing the catch holes.

15mm plywood case with aluminium lid extrusion.
It is usual clamp the lid in position to route the holes (using a template) straight thru the extrusion timber & all with a 1/2" bit.

any way he was up to the fourth catch & notice that the progress was a little slow, but completed the cut. Thaught the bit was going blunt. (o well)

upon removing the lid to clean up, He noticed he had routed thru the end of the3mm x 20mm steel reinforcing hoop on the last catch.

O!!!!

checked the router bit. no chips no burns & no nasty blunting.

???????

Not a recommended procedure but a good testimony to good quality router bits.

Quote from "The New Router Handbook" - Spielman

pp74 - "Incidentally, spiral bits are the bits to use for cutting aluminum."

Soundman - reminds me of the time I took a good portion off the heads of two M12 bolts with a tct straight cutter. No chipping or anything. It did send a shiver down my spine though. How I misjudged their location was a lesson to remember.

TCT tools were used for cutting steel long before wood. They have been used in lathe and milling tools for ages. Any material can be cut at long as the cutter is harder and the speed and feed rates are right. I wouldn't recommend using a router to cut steel though, it runs way too fast and you would probably throw the teeth off the cutter and into your much softer fleshy bits.

All the best,

Dan