Step 8: Building the Superstructure : Making the Centershaft/Axle 1
You are going to need a centershaft/axle, with 'baskets' to hold the honey frames. This axle will be aligned in the center of your extractor, DEAD center of your 'liner' (which catches the honey), and will mount into your bearing blocks/bearings at the top support, and bottom support connection points.
In my construction, I made this step WAY too complicated. I'll detail my process I carried out here anyway...but you can save this entire mess (of adapting square tubing to round bearing receivers), if you simply use round tubing for your entire axle. For instance, if you are using 3/4" Internal Diameter (ID) bearings , then simply choose a piece of heavy walled 3/4" Outer Diameter (OD) stainless tubing as your shaft material, and you won't have to make any special end pieces/etc to adapt to the bearings...your tubing will slip right into your axle bearings, with no lathe/other heavy equipment involved.
In my case, however, I used square tubing for the center portion of the axle...and hence, I had to fabricate axle ends which adapted the square axle to mount in the (obviously) round bearing receivers.
So....to do this (overly complicated, and unnecessary) task:
I selected the same 1" light wall tubing I've used in the other parts of construction. You will need to have an axle length AT LEAST long enough to accommodate the fact that your honeycomb hive frames are 19" in width. I calculated my center axle length as 19" plus about 4" on each end to receive the bearing axle adapters, making my center axle length 27" initially (although, I trimmed this down later during test fitting). Since you have already built and test fitted your upper and lower support structures, you can measure the distance between your bearing to get an idea of your axle lenght.
Cut yourself a center axle piece to length, using the preceding measurement you took.
To adapt the square tubing to the round bearings, you'll need to fabricate an adapter.
For this adapter, wyu can choose a piece of 'round stock steel' (a round bar of steel) of size 1". You can see in the photo that this is obviously the same size in diameter as our 1" square tubing.
Mount your 1" round stock up in the lathe, and turn it down until it's just small enough to slip INSIDE your 1" square tubing (this will vary, based on your 1" tubing wall thickness). Try to get a tight fit, to save having to do any alignments. A sloppy fit will lead to a wobbly axle. You want it to slip perfectly in the square tubing, with NO play at all.
You will want to have at least 1.5" in length of this shaft INSIDE the square tubing for strength.
Now, leaving yourself 1.5" of the freshly turned round stock, turn down the rest of the piece to the internal diameter (ID) size of your bearings. In my case, this was 3/4". Again, you want to shoot for a snug fit...as sloppy fit will lead to vibration of your axle.
You should now have a length of square tubing which comprises the center of the axle, and two end pieces of solid steel, which fit snuggly into the end of that square tubing, and also into the bearing sleeves (see photos for details).
Now that you have two finished axle ends, insert them into your square tubing piece of axle you have cut to length, and center punch a mark to cross drill the tube AND axle (see photo). This will allow you to pass a bolt through the axle end, and the square axle tubing, and still let you disassemble the axle unit, if necessary.