Surfacing aluminum parts

Yes. A sheet of plate glass may be flatter than your table saw. You
can get abrasive dust, diamond dust or whatever, and grind the metal
against the glass with a slurry of abrasive and water in between.

Depending on how non-flat your aluminum is, I would do it like you flatten a plane sole. A piece of glass, or other flat surface, some sandpaper, and a spray bottle of water.

I would probably start with a 120 grit and work my way up to whatever grit gives you the surface you want.

-- Adversity doesn't build character...................it reveals it.

+1×2 ^ ... the first like a lapmaster and the 2nd like a plane sole. Either will work and the aluminum will not take forever. You don’t state the gauge of the material, but if very thin (i.e flexible / easily deflected) ) then do not push down too hard or you’ll never get it flat.

-- If you're going to stir the pot, think BIG spoon or SMALL boat paddle. David Grimes, Georgia

do it like you would a plane sole

-- When the moderator chooses sides, his site sucks.

I have heard of people grinding aluminum with some hard and soft rubber wheels of some sort. I have heard that it is dangerous to grind aluminum on a grinder that you also use to grind steel with because of mixing aluminum with steel particles. It’s a safety hazard. However, I don’t have a lot of experience with machining aluminum because we use mostly steel and cast iron in our machine shop.

-- If a man does not keep pace with his companions, perhaps it is because he hears a different drummer. Let him step to the music which he hears, however measured or far away. Henry David Thoreau

Thanks for the suggestions.

The parts are about 1/4” thick, so I don’t think they will flex significantly.

Will window glass work?

I know people flatten plane soles doing something like this, but I don’t know the details. Since Sawkerf suggests a spray bottle, do I need to get a particular type of sand paper? I was going to glue down some sandpaper and have at it.

-- Greg D. -- the price of freedom is tolerance

Use wet and dry sand paper. I wouldn’t think you would need to use 120 if you are only taking off .002”. Maybe though….I am no expert in this area. Wet and dry cuts pretty quickly when you keep it wet.

I use a piece of solid surface counter material and wet/dry sandpaper. I spritz the solid surface material to hold the sand paper, then spritz the sandpaper before I start lapping. I use this method to sharpen plane irons and chisels (with finer grits, of course) and have used it with coarser sandpaper to flatten 4-5 plane soles.

-- Adversity doesn't build character...................it reveals it.

Great. Thanks for the help.

-- Greg D. -- the price of freedom is tolerance