Step 2: Make the Shank
This part will be very easy for anyone with some machining experience, for instance I am 15 and just purchased a South Bend benchtop lathe and this entire project was done with this. I will put some machinist drawings in to make this part of the project much easier. This took me about 7 hours on the lathe to make so make sure you have some time. This is where you with be using the 1-1/2 inch aluminum. You should put this piece into your lathe in between the chuck and the tailstock. Just follow the drawings for this step. Also the two ends of this shank will be fit into the bearings so machine them to the inner diameter of your bearing not mine, unless they are the same size, in that case make it like mine. Please click on the Machinist Layout file to get the dimensions of this part. Also if you have any trouble understanding these dimensions please contact me and I will try to help you out. Note that this picture is not drawn to scale.
Step 3: Retaining Ring
This ring will be the exact same size as the larger portion of the shank. All this will do is ensure that all of the hard drive platters and rings will stay onto the shank. I will once again put a machinist’s diagram into the pictures to make it easier to understand. In this piece you will also have to drill and tap a hole for an 8-32 set screw. This will make sure that the ring does not come off. Again if you have any problems understanding the image please contact me. This picture is also not drawn to scale.
Step 4: Drill Holes in Hard Drive Platters
The drilling of these holes should be fairly easy, all you will need for this is a drill press, but a milling machine would make it easier. I just used a drill press. You will need to drill eight holes 25 mm from the center of the hard drive disk. These holes will be spaced 45 degrees apart. You can easily plot this out on a piece of graph paper with a protractor before you drill it to ensure it is correct spacing and everything. And it is ok if the holes are not at the exact space on every disk because they are not on mine and it works just fine; just make sure they are no more that .030″ difference. When drilling these holes remember to use a sheet metal drill unless you figure out a way to keep them all together while drilling, because it will warp your hard drives. Also you may want to look at the hard drive layout file for some help on what to do to lay it out. You will need to make eight of these. Ohya and use a 3/8″ drill bit for this. Also do not use the diagram that I made because the holes on that are too far off the make this project be same, it WILL be off-balanced if you were to use that it is just an example to help you.