Introduction: Making an Aluminium Wheel Hub
In this instructable I show you how to make a wheel hub for a go kart or minibike from just scrap aluminium! so the wheels I bought were for an atv, so I couldn't buy any hubs for my 25mm axle. Well lucky for me I had an aluminium melting furnace and a lathe so it wasn't much of a problem to make one. If you have a lathe and aluminium foundry you should be able to do this, just make sure you have some way of cutting an internal keyway in the final hub cause I ended up just using a file and it was waaaay too much work.
anyway before getting started, have a look at the video!
Step 1: What You Need
So heres some tools and materials you will need:
hot glue gun
sandpaper and razor for shaping foam
pliers (long nose)
power drill and drill bits
angle grinder to clean up the finished product
some bolts and a tap to match
25mm drill for lathe (or whatever size axle you have)
something to cut an internal keyway on the lathe, or a file.
aluminium foundry with crucible and all that...
big block of foam
some fuel for your foundry (mines coal)
and thats basically it!
Step 2: Shape the Foam
So I started off by hot gluing a bit of metal in the foam so I could sand it on the drill. This made it really easy to get the circular shape I wanted my wheel hub to be. I also made a basic template on cad and printed it off so I could cut the rest with a razor or something. Sanding it in the drill involves spinning the foam block really fast and just holding some sandpaper up against it until its sanded down to the thickness you need.
Step 3: Getting Ready to Cast
So before you cast, you want to bury the foam with sand. I use a little bit of old car oil in the sand to help it stick together, but it stinks so stand back after casting. Bury it until only the top is showing and shape the sand around it so it will all go into where the foam is. To start my furnace, I fill it halfway with charcoal, then chuck some petrol on and light it up. you can see in the pictures that I use a car battery and air mattress pump to fan the furnace. The furnace is just an oil tin with a mixture of sand and plaster set with some steel wool so it doesn't fall apart. Its a good idea to put some more coals on top once it is lit. definitely have some scrap aluminium ready and cleaned up before lighting the furnace. Cleaning the aluminium is essential if you don't want too much slag.
Step 4: Start Melting Some Aluminium!
I usually put the crucible in right from the start so that it heats up as quick as possible. Mine is homemade, welded from stainless steel which works really well as it doesn't deteriorate anywhere near as fast as mild steel. then theres some hooks I made up to hold it. in the pictures you can see I pre heated the propeller before melting it just to make the process quicker.
Step 5: Casting the Aluminium
Keep adding aluminium until the crucible is full. Once it is, you want to scrape the slag off the top. It is easy to see and ruins your cast if you don't remove it. I just use a bit of wire to take it out until all thats left is the liquid metal. Before casting, make sure there is no loose sand on top of the foam. Pour slowly and carefully, it got a bit smoky for me but I just tried to keep pouring in the middle. Keep pouring until there is a small puddle at the top of the sand. Give it a good half hour to make sure it is solid before removing the casting form the sand. I made four of these.
Step 6: Final Machining
Alright so I don't have many pictures of drilling out the stud holes, but its pretty straightforward. So I started off by drilling out the middle on the lathe, then drilled out the stud holes. Two more holes in the side with bolts to lock the hub in place on the axle. These need to be tapped out. And finally making the keyway. If you have something to do this on the lathe it will make it so much easier but I just had a file so that took a long time. and thats all you need to do.
Step 7: Done!
Its for the back wheel of my minibike, and you could never tell I made it myself!
Once I'm done the minibike I might make an instructable of that...
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