Introduction: Aluminium Milling

Picture of Aluminium Milling

I have been building a funky bike shed that I call a Bike Wardrobe and I needed to mill a slot in some 5mm thick aluminium sheeting for the locking throw bolt.

A quick search on YouTube taught me how to do it and I was amazed at achieving this for the very first time!

Come with me and I will show you how to do it as well...

Step 1: Bits That You Will Need

Picture of Bits That You Will Need

MATERIALS

Aluminium [aluminum] sheet, mine was 5mm thick.

Off cuts of MDF or ply for jig

Some screws

TOOLS

Electric router, I use a 1/2" router though a 1/4" should do also

High speed steel [HSS] router cutter for wood, I used a plunge cut one with cutter profiles on the bottom as well as the side, width to suit the milled slot.

Screwdriver

Cordless/power drill

Selection of drill bits + countersink

Step 2: Prepare Your Router

Picture of Prepare Your Router

Remove the plastic base plate from your router.

Cut a piece of ply/MDF [I used 4mm thick] to a larger size than the base of the router to allow it to be screwed to the jig.

Cut a slot from it to allow the cutter to plunge freely and to enable you to see the progress of the milling.

Carefully mark the fixing holes from the base of the router and drill and countersink the ply for re-fixing back onto the base of the router.

Step 3: Make Your Jig

Picture of Make Your Jig

A jig is just a device that holds your tool [router] and guides the material [aluminium].

I required a strip of aluminium about 50mm wide which I cut by hand!

The jig design will be dependent on the shape and size of the piece of aluminium that you need to mill.

I cut two pieces of 6mm thick MDF and fixed them to a thicker 18mm MDF to hold the aluminium strip though allowing it to slide without any play side to side.

The router and its ply base was screwed to this MDF jig centrally as I needed the slot in the middle of the strip.

The whole jig was screwed securely down to the work bench, important that there is no movement in the jig.

Fix a screw at either end of the aluminium strip at the desired extent of the slot to act as stops.

I was fortunate to have a tapped hole that I inserted a bolt into to make the sliding of the strip easier, sticking a tab of duck tape to the aluminium strip should work as well.

Check that all is screwed down securely, that the router will plunge the full depth that you require and that the aluminium strip will slide.

Step 4: Mill

Picture of Mill

Please wear ear defenders and eye protection, you know it makes sense!

Switch on and slowly plunge until the cutter cuts into the aluminium.

I found that only a fraction of a millimeter was possible to mill at each pass.

Listen to the sound of the cutter to determine that the cutter was not being put under any strain.

Slowly slide the aluminium strip until it reaches the stop and return to the starting position.

Repeat the process until at the desired depth.

For my 5mm thick piece it probably took about 12 to 14 cuts to mill all the way through. Deeper milling should be possible up to the depth of the router cutter.

Release the plunge and switch off the router.

Step 5: Fantastic!

Picture of Fantastic!

Remove the aluminium strip from the jig...

...and you have a perfect milled slot.

FANTASTIC!

This Instructable resulted from my recent project the Bike Wardrobe that I designed and built with my design company pricklysauce.

I love learning new skills and I am still amazed that within a few minutes of searching the internet and YouTube that you can learn enough to tackle something that you have never done before.

I hope that you have enjoyed this Instructable and maybe you will also learn a new skill! If you liked it, your vote in the Beyond The Comfort Zone Contest would be really welcomed. Thanks.

If you would like to check out the build of the Bike Wardrobe please click here to go to my YouTube channel, where you will also find my Its a Rubbish Challenge videos where I try to make interesting things out of the stuff that we throw away.

Comments

Stan1y (author)2016-06-01

thank you for proving something I've thought for awhile, that a router can be used as the basis for a vertical milling machine

Pricklysauce (author)Stan1y2016-06-01

Seems to work well, though please remember this one only works with aluminium.
Please check out comments below that mentions the type of aluminium to use, though I have no idea what type I used for the project!

SergeE (author)2016-05-30

Next step : make yourself a CNC Router. A complete 'metal plate cutter' kit is available over at www.OpenBuilds.com. I made a large (52" x 20") : myOX @ http://openbuilds.org/builds/myox-a-4-x-2-ox-cnc-w... buying parts from here & there, following their base OX as a model and using my full size router.

You will be able to cut just about any shape, pockets, etc. in wood, plastic and aluminum.

Pricklysauce (author)SergeE2016-05-31

Hey Serge - a CNC build is on my list! I have just bought an Arduino to start playing around at converting an old drafting table into a basic plotter/cutting table, then onto a full size ply sheet CNC machine. My hope would be to use it for cutting things like aluminium and plastics as well.

Thanks for the link to OpenBuilds, looks like a good site.

SergeE (author)Pricklysauce2016-05-31

That's a great idea : converting your old drafting table into a plotter / cutting table. It would make for a great Instructables.

OpenBuilds got me into CNC as I always thought it would be too difficult and expensive. The OX design is an economical and practical approach used by many DIY/Makers to make their own machines.

cheezedog (author)2016-05-30

Wow.. that worked perfectly! Can you figure out how to cut in the X and Y direction using this method? I could see if you figured that out being a good way to cut big slots, and square recesses.

SergeE (author)cheezedog2016-05-30

Checkout www.OpenBuilds.com. You might want to build yourself a CNC Router ...

cheezedog (author)SergeE2016-05-30

This is nice.. but for quickly cutting out a box shaped hole, It's overkill. I Just want to be able to put a block of metal down, hack out a hole with my eyeball, and then go on with my project.

I will look into this since eventually I like to take over space all territory beyond.

SergeE (author)cheezedog2016-05-31

If all you want is to do the odd pocket once in a blue moon, it would be overkill. But you might get bit by the bug to do more and tricker designs, ... ;) It's then that you will start looking into making your very own CNC machine.

While the CNC does the pockets and cuts, you work other aspect of projects... The eyeball, fingers, etc. staying at a safe distance.

Pricklysauce (author)cheezedog2016-05-31

Hey Cheezedog, I guess the easiest way would be to make one slot and re-position the router over the jig to make a second pass to the full width of the slot that you want.

Otherwise with a bit of thought I am sure a jig could be made up that would allow for X+Y cutting.

Just be aware that the whole assembly has to be tightly secured down as Jonmero pointed out below, no freehand milling.

If you figure it out let us know how you got on.

jonnmero (author)2016-05-30

Sorry being a spoilsport, but using woodworking router for aluminium is generally not a good idea, because if something goes wrong and you get a catch, things can become horribly messy! And if you still do this, be sure to get a machineable aluminium alloy. The soft ones will easily cling to the tool, especially one like a high speed router.
The other thing that should be pointed out is that this kind of practice freehand is definitely a no-no.
This just in case someone thinking of short-cuts! Other than that, have fun!!

Pricklysauce (author)jonnmero2016-05-30

Fair advice, though it seemed to work okay if taken with very small depth increments.

Sure as my Instructable and video show, everything needs to be firmly secured down. I even screwed the whole jig to the workbench as I didn't want a clamp coming loose.

If taken slowly and with care it seems to be an effective way for an occasional use.

Definitely would never do this freehand

gm280 (author)2016-05-29

Yes, aluminum can be easily cut with table saws, routers, chop saws, band saws and most any woodworking power tool if you go easy. And if you can get milling bits it works even easier. I have cut 1/2" thick aluminum with my chop saw numerous times. Thanks for showing your technique.

Pricklysauce (author)gm2802016-05-29

Hey gm280 - Wow that makes it even easier! I could have saved myself from cutting the strip by hand! I should have used my bandsaw. Thanks for the advice.

WoodCrafts 67 (author)2016-05-29

Nice Job Mate. I have Used this process a few times and it works very well. Great Instructable.. Looking forward to seeing more. Voted :)

Hey thank you, I really love learning a new skill, just opens up more opportunities. Thanks for the vote.

BeachsideHank (author)2016-05-28

I use a 1-1/2" [38mm] carbide tipped woodworking planer bit in my milling machine to surface down aluminum castings, works great too. With a router though, it produces needle- like shards when cut at that very high speed, so absolutely do wear personal protective gear. Most woodworking bits fare quite well on aluminum, especially useful are the roundover bits for treating the edges of it.

Hey BeachsideHank thanks for your experience. As I say in the video I work with wood and this was my first attempt at milling aluminium. Definitely protect your eyes, don't want to be getting any off the bits in there.

I hadn't thought about other cutter shapes, may give that a go.

I use my woodworking bits simply because I have plenty of them, and 2 flutes give the best results for cutting ally. They are about 1/3- 1/2 less in price than similar ones from metalwork supply houses and although metal cutters use a different carbide grade, I don't notice any substantial difference in performance.

Plus I'm cheap. ☺

I would say you were 'sensible' not cheap!

tljiha (author)2016-05-28

I use methylated spirits as cooling lubricant when processing aluminium

Pricklysauce (author)tljiha2016-05-29

Thanks Tljiha, any tips are most welcome as I am a complete novice in working with metal.

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