I managed to get a little more work done on the bandsaw tonight. With the discovery that the ball bearings used for the blade guides were shot, I decided to do a closer inspection of the bearings on the wheels. To get to them I had to disassemble some more of the saw. To remove the wheels requires removing the nuts in the center of each wheel. Once the center nuts are removed from each wheel they can be removed from the saw. On the bottom wheel you’ll need to hold the wheel in one hand and pull on the wrench with the other to keep the shaft from spinning. On the top wheel, the bearings fit inside the wheel hub. On the bottom wheel, the bearings are in the saw body.
I was able to find an instruction manual and parts diagram for a saw like mine at vintagemachinery.org. If you’re into old wood and metal working machines this site and owwm.org are priceless. The parts diagram showed the two bearings fit into the top wheel on the front and back. Behind each bearing was a ring or clip and in the center is a spacer. The question it doesn’t answer is if the ring/clip just sits in there to take up space or if it fits into a groove in the wheel. It’s a little, but important, detail. If the rings don’t fit in a groove then I can press the whole stack out with my arbor press. On the other hand, if there is a groove they fit into, then attempting to press them out would break things. Unfortunately, the gap between the spacer and the bearings, the width of the ring/clip, is very small so I was not able to drive the bearing out from the opposite side. There is a tool called a blind hole bearing puller that is made for situations like this. You insert an expandable collar into the hole in the center of the bearing and expand it so that it grips the bearing. From here you can remove it with a slide hammer. Unfortunately, I don’t have one of these. Shocking I know. Looking around online I think you can rent them from autoparts stores. Before I went off to find one I decided I’d lightly press on the bearing stack to see if it would move. It did every so slightly and I was rewarded by the site that the space had moved as seen in the picture below.
With the spacer out of the way I was able to insert a metal bar and tap the bearing out of the opposite side.
So, what were the clips/rings? Was there a groove? Yes, there is a grove and a snap ring fits into it. Any attempt to press the stack out of one side would have been unsuccessful and might have possibly damaged the wheel. It is a good reminder to go slow and think about what you’re doing before you break something. I think I recall my dad saying that once or twice.
With the bearings out I could rotate them and see how they felt. They are both definitely on the way out. They would rotate but you could feel some lumpiness. They’ll need to be replaced. From now on I think I’ll just assume all bearings are bad and plan to replace them before they end up tearing something else. Below you can see the spacer and the two bearings. They’re 6202Z bearings if someone stumbles across this page that that info could help.
With the bottom wheel removed you can see the bearings in the body casting but the shaft has to be removed first. To do this you have to remove another nut on the front of the shaft and one on the back. To remove the one on the back requires putting the wheel back on the shaft so you have something to hold against while loosening the nut. Once both nuts are removed the shaft can be driven from the back of the machine out the front. When the shaft came out it removed the front bearing with it which simplified things. The back bearing was a little more stubborn. So, I used the lathe to rough down a piece of wood to drive the rear bearing out.
Here’s a picture of the shaft and bearings for the bottom wheel. The front is on the left in the picture below. These bearings are 6204L. Incase you’re curious the bar sticking up from the shaft is a called a Woodruff Key. A Woodruff key is a half moon shaped piece of steel that fits in to a void cut into the shaft. It keeps the wheel from rotating on the shaft and can be easily removed and replaced if needed. Clearly, it has to be removed to get the bearing of the shaft. The other side of the shaft uses a parallel or square key to keep the pulley from rotating on the shaft. I’m sure both designs have benefits but I’m unaware of them currently.
I’ve previously said that the tires need to be replaced on the saw. On a bandsaw the tire is a circle of rubber or urethane that goes on the outside of the wheel to help grip the blade. Rubber tires are often glued down while urethane ones just stretch over the wheel. On some bandaws the wheels/tires have what is called a”crown” on them. The “crown” is where the center of the wheel/tire is raised higher than the edges. In other words, the outward edge of the wheel/tire is convex or radiused. This helps with blade tracking and keeping the blade on the wheels. As you can see in the picture below, the tires are worn so much that the crown is completely gone and has been replaced by a depression. On this saw, the wheels are convexed and the tires are a constant thickness. So the wear of this tire is greater than it initially appears.
In addition to the depression you can see the imprint of the blade and that the tire has dry rotted and cracked. Not good.
To remove the tires was pretty easy. I slit it with a razor blade, pried an end up, and then pulled it off. Of course it didn’t come off cleanly and left glue and bits of rubber in place.
To remove the left over pieces, I used a combination of acetone with a rag, scraping, and wire wheeling. A tiny wire wheel on a Dremel worked well for getting into the corners. To get the last bits out required a razor blade again.
After a good deal of work the wheels were both cleaned up and are ready for new tires.
I also picked up a new plug and put it on the end of the cord. Now I can run the motor in a less risky manner.
For new bearings I called Lynee at Accurate Bearings. Accurate is recommended on the OWWM.org website and I’ve had good experiences with them. They provide high quality bearings from multiple manufactures at good prices. They also don’t overcharge you for shipping. So, if you need bearings for your machine, give them a call. OWWM has a bearing exchange chart from Accurate to find your bearings. So, what I said in the last post about using cheapie bearings on the guides is no more as I also ordered some of them as well. Now I’m waiting for tires and bearings to arrive.