I decided to make a shaft with bearings after my first trials trying to make a homemade disc sander with the drill. The thing is, that’s when I realized that it is very difficult to get the sanding disc to spin flat, without wobbling. This is mainly due to the fact that the drill chuck does not rotate in a fixed axis, but has a small play that causes it to give way to where the sanding disc presses (something to keep in mind in our homemade drill powered machines). As a result, I found the disc impossible to true. You can watch the video at the end of this post.
To make this shaft with bearings, I’m going to use a piece of steel pipe. And at the ends of this pipe I’m going to fit two ball bearings. The bearings are going to fit very tightly around the steel pipe, but that’s what I found.
I would give you the dimensions, but the best thing to do is to find a threaded rod, pipes and bearings that fit as well as possible. Without focusing on a specific measure. In my case, the important thing was that the distance between one bearing and the other was not too big, because I don’t want to have to make a very wide support for them. But for other homemade machines that I’d like to make, I might need more distance between bearings. Or also a thicker threaded rod.
I also need a piece of copper pipe that fits snugly, as a sleeve, around the steel pipe that will work as the shaft. And the copper pipe plus the two bearings should measure the same as the piece of steel pipe.
Then, once I have the pipe pieces cut and after cleaning the burrs with a fine metal file, I have to put a threaded rod inside the steel pipe. So I screw two nuts, locking one against the other, in one end of the rod. I clamp the piece of pipe into the vise, and with the wrench around one of the nuts, I turn the rod so that it threads into the pipe. It fits very tight, as it has to “carve” the thread as it goes in.
And now I have to fit the bearings on the ends of the steel pipe. So, I put a large washer on one of the holes in my workbench, and I put a bearing on it. I place the steel pipe on the bearing inner ring, and trying to keep it vertical, I tap it so that it gradually enters the ring.
I cooled the steel pipe in the refrigerator, but it still fits very tightly. But finally I did manage to get it in.
Now I put the piece of copper pipe as a sleeve around the steel shaft. And I put the second bearing in the same way I put the first one. Thus the copper sleeve will maintain the clearance between the two bearings.
To prevent the bearings from coming out, I put a small washer and a nut on each end. And with a pair of wrenches I tighten the nuts against the washers. In this way the washers press only the inner ring of the bearings, but the outer ring will continue to rotate freely. And inside the shaft, the inner ring of each bearing is pressed against the copper sleeve.
To keep the nuts from loosening, I put a pair of self-locking nuts on each end. And so I have ready this shaft with bearings that I can use in some of my homemade woodworking machines. Although as I said, in this case it is to make a homemade disc sander that will work powered with a drill.
And below we can see the video in which I talk about the problems of making a disk sander with the disk spindle connected directly to the drill chuck.