Replies

1. 
   John_Casteen_ | Mar 03, 2002 02:08am | #1

   *
   Tim,

   Look at http://www.sawcenter.com/unisaw.htm. I think Kelly Mehler's book details the process, too.

   Conover's The Lathe Book shows a nifty way to press bearings on and off with a tail vise and a mandrel you make in the shop. I usually use a 3-jaw gear puller on the pull and a machine shop's hydraulic press on the push.

   Good luck.

   John Casteen
   Fern Hill Furniture Works
   Earlysville, Va.

1. 
   Jeff_Patrick | Mar 03, 2002 04:48am | #2

   *I replaced my arbor bearings only about two months ago. They were making a very funny noise and I found I couldn't get an accurate miter cut. I think there was too much play in the arbor and it affected the cut drastically.The job is very easy, except that one has to sit on the floor in an awkward position. You do not have to remove the top, although that would make the bearing job easier. I chose to not remove my top because that would have been a big job all by itself. I had a pal help in the removal process. He pushed a banged while I kept things lined up. The bearings are not "pressed " on to the arbor shaft. I found a bit of rust on my shaft which meant the bearings were a bit sticky to remove, but after cleaning this surface rust, I simply slid the bearings on with only a few taps with a hammer. I did not use nor did I need a bearing puller. Good luck. If you need any further advice or have specific questions don't hesitate to ask.jeff

1. 
   DWMoser | Mar 03, 2002 09:41am | #3

   *Tim:Follow the link to the Sawcenter that John posted and you will see some excellent photos of what’s involved to replace your Unisaw bearings. I have replaced bearings and arbor shafts in a couple of Unisaws and it is not difficult - time consuming but not hard. Tap the old bearings out with a hammer and punch and tap the new ones in with a hammer and a block of wood. Don’t get too carried away with the hammer when re-installing and you should be OK. I have always taken the top off my saws when doing this type of work. I really can’t imagine doing it without removing the top. Jeff - you got pictures of how you did that? I’m thinking what you call “awkward” I would call impossible. Unless I was about 2 1/2’ tall and could just “get in” my Unisaw. Curious.Anyway Tim, you didn’t say why you wanted to replace the bearings - as in what is the saw doing? It seems to me that 0.003” is within Delta’s tolerance for runout on a Unisaw. I know I called and asked a while back. Can’t find the information right now, but I’ll keep looking. You sure you need to replace the bearings? Dave

1. 
   John_Casteen_ | Mar 03, 2002 09:04pm | #4

   *I've been warned repeatedly by people who know a lot more about this stuff than I do that driving new bearings onto the shaft with a hammer, even very gently, defeats the purpose of replacing the bearings in the first place. As it's been described to me, the difference between a hard blow and a soft one is about the same on the balls of the bearing; they get dented more or less equally regardless of the force of the blow because they're held in the races by such a close-tolerance fit. Thus it's better to correct wobble in a drill-press chuck by smacking it once or twice like you mean it, rather than giving a series of gentler taps. And, the wisdom goes, better not to hit your new bearings at all. I do follow this advice and buy the services of someone with access to an arbor press simply because it's already so expensive in terms of time to have a machine out of service and to devote shop time to the bearing work; then there's the cost of the bearings themselves. I don't want to do it any more frequently than I have to.John Casteen

1. 
   CStanford_ | Mar 03, 2002 11:23pm | #5

   *You were told right, John.

2. 
   Jeff_Patrick | Mar 04, 2002 02:04am | #6

   *All that philosophy regarding how hard to hit or even should one even hammer in the first place is really a mute point in this case of the Unisaw. I basically pushed the bearings on by prying with an 18"+- length of wood. The bearing on a unisaw arbor must be installed in the machine or one must remove the trunion and take the whole thing to a machine shop where they will probably push the bearings on with their hands. This job is a piece of cake. I just replaced bearings in a Makita router that gave me more trouble.Dave -- I removed my motor cover for access, dropped the motor as far out of the way as possible (crank it either up or down to give the most clearance), and reached in. You will need the assistance of a helper to remove the arbor. I put it all back together by myself. The job can be done from below, but one must be fairly limber and not too big. I chose to work in this awkward position for a while rather than remove the top which would be a major hassle in itself.One more thing. My endeavor began because I noticed the belts to be vibrating rather excessively. It was only after I removed the belts that I noticed how bad the bearings really were. In any case, I would recommend anyone doing the bearing job to go ahead and replace the belts at the same time. For a few dollars, it is money well spent.

3. 
   CStanford_ | Mar 04, 2002 02:24pm | #7

   *Ahheemmm, well, harummpphh, too much of a softball... anybody else wanna go with this one?I almost can't speak.... :-)

4. 
   Tim_Lawson | Mar 15, 2002 01:45pm | #8

   *Belated but sincere thanks to everybody for their comments and advice. I'll be tackling this next week.Tim

5. 
   Rickk_ | Mar 17, 2002 02:56pm | #9

   *You never mentioned as to the age of your saw. The older ones, sixties and beyond, used a bearing with an extended inner race. If your saw has the older bearings you will need to replace the short arbor spacers with longer ones so that you can use standard bearings. Just a thought. No one mentioned anything about the age factor. I would definitely remove the top to change the bearings. I spent 8 years servicing Delta and other machines for a dealer and have changed more arbor bearings on unisaws than most people I would reckon.