How to Cast and Machine Aluminum Rollers

Intro
My buddy and I have been talking about casting aluminum for a while and I needed end caps to stuff into the stainless steel rollers I had knurled for a grain mill.  It seemed like a perfect match for a project.   

So I am in the process of building a monster grain mill (later instructable?) for my brewing hobby. Yes, I can buy a mill for $150 give or take but then where is the fun in that?  

Things to consider before beginning:
You are dealing with molten metal.  It is serious.  Do not attempt while intoxicated or on the way to such a state.  Imagine that feeling you get when you burn your tongue on cheese of a pizza that was eaten too soon after coming out of the oven.  It is like that only times 10 on whatever the metal has dropped onto.  It is really hot.  We took the precaution of using welding gloves, eye protection, leather aprons, work boots, long pants even thought it was 90+ degrees out.

Here are some of the things you will need to duplicate this adventure:
CASTING
-foam insulation board (from local hardware store) this is the open cell stuff that shapes well
-drill press, while not required technically, very helpful
-drill the size of the following bolt
-files and rasps
-steel bolt and washers
-scrap aluminum
-flame thrower (the kind they use to melt tar on roofs) like this
-crucible (we are using 1/2 inch 4x4 steel square stock with a 1/2 inch plate welded to the bottom) for holding the melted aluminum
-firebricks or regular for making a furnace/oven to heat the metal in

MACHINING
-desktop lathe made or bought

Step 1 Making the lost foam template

Using the foam insulation and a sharp blade, cut squares roughly larger that the final roller diameter by maybe 1/8 of an inch and mark the center point.  from the center mark the radius of the final diameter with a line.

Comments

[bobbuilder09]

very detailed explaination of a pizza burn, but what you have not explained is that molten aluminium at aprox 650 degrees c would probably burn through the nerve endings under the skin (cortorise the bleeding and contunue burning and cooking the flesh untill it hits bone or cools down, (maybe leaving a hole when it exits and falls on the floor), you would probably smell burning flesh before you realised what had gone wrong!, the pain would come later when the signals from the damaged nerve endings eventually get to the brain, well done in pointing out eye protection, leather gloves, apron workboots and a large amount of caution and common sense are needed i would say, but the risk is entirely the individuals choice

[lemonie]

Nice piece. How are you intending to ream-out the centre for however you'll be mounting this with the bearings?

L

[Farmer-Al]

because of bad planning, I may have to tap the center hole and put a stud in it with some thread lock, put that in the chuck an turn the inside.

[lemonie]

Bearings in the Al' then?

L

[Farmer-Al]

Yeah, I have 4 5/8 center hole bearings so I could use off the shelf rod to mount it to the to-be-made frame...

[rimar2000]

Very good work!

[bilge17]

Good job on your first instructable..... I would like to see just a little more detail on the different stages (i.e. Aluminum melting process, casting sand mixtures, and just a little bit more about the lost foam method and the sprue). These are items I would like to see more about personally. Good job, can't wait to see the Grain Mill 'ible'.