I decided to make a shaft with ball bearings after trying to make a drill powered disc sander. When rectifying the disc sander disc, I realised that it wasn’t a good idea to connect the disc shaft directly to the drill chuck. Because there is always some play in the drill chuck (something to keep in mind when we make our drill powered machines and contraptions), so the sanding disc wobbles. And it is almost impossible to rectify the front of the disc. You can watch the video at the end of this post.
I will use a piece of steel pipe to make the shaft. And I will fit one bearing in each end of that steel pipe. The bearings I use will fit very tight around the pipe, but I use the pipe and the bearings I could find.
I could give you the diameters, but if you want to make this shaft it is better if you look for a threaded rod, pipes and bearings that fit together as nice as possible. Anyway, in my case the important was to make a shaft that is not very long. Otherwise, when making the disc sander I should have to make a wide support. Maybe if I use this kind of shaft with bearings to make other machines and contraptions, I’ll have to make it some longer. And I could even need a thicker threaded rod.
I also need a piece of copper pipe. It must fit as perfect as possible around the steel pipe. Like a sleeve. And the copper pipe plus the bearings must be as long as the steel pipe.
Then, once I’ve cut the pieces of pipe I need, and after using a file to clean the burrs, I have to insert the threaded rod inside the steel pipe. So I tighten two nuts, one against the other, in the end of the threaded rod. Now I clamp the pipe with the workbench vice, and with the help of a wrench I screw the threaded rod inside the pipe. It fits too tight, because it has to “carve” the thread inside the pipe.
And now I have to fit the ends of the steel pipe inside the bearings holes. So I put a big washer on one of the holes in the top of the workbench. And I put a bearing on that washer. I put the steel pipe with the threaded rod vertically on the bearing, and I hit the threaded rod until the pipe enters inside the hole of the bearing.
Before that, I cool the steel pipe (together with the threaded rod) in the refrigerator. But even so it fits too tight. But finally I could insert it.
Now I put the copper pipe around the steel pipe. Like a sleeve. And I insert the other end of the steel pipe in the hole in the other bearing. Like this the copper sleeve with keep the distance between both bearings.
To make sure the bearings won’t get out of the pipe, I put a small washer and a nut against each one. And I tight the nuts against the washers. Like this the nuts only press against the small metallic ring of the bearings, while the big metallic rings still turn free.
And now the ball bearings shaft is ready to use in my homemade disc sander, or in others DIY woodworking machines.
Next we can watch the video about the problems I had to rectify the sanding disc when I connected it directly to the drill chuck.