2. analog
  3. 1185196965

How to remove a 'press fit' steel ball bearing?

I'm doing some work to my Russco turntable. I need to replace the ball bearing in platter shaft. This bearing is pressed into the end of the platter shaft and cannot be just 'popped' out. It has to be forced / pulled out. Being pressed into the shaft, there is no way to get a grip on it to pull it out. Someone suggested that I heat the end of the shaft which would cause it to expand so the hole in the shaft would get bigger and the ball bearing would drop out. I tried that to no avail. Someone else tried to explain a removal method but I think he never really understood how this bearing is set. So, I'm going to try to explain this so that it is more clear.

Imagine that you are holding in your hand a 6" long steel rod of about 1" diameter. You turn that rod so that you are looking directly at one of the ends (you are seeing a 1" diameter circle). In the center of this end a hole of about 3/8" has been drilled. Into this 3/8" hole a ball bearing has been pressed so that approximately 1/2 of that steel ball bearing protrudes from the end of the shaft. How do you remove it?
kwillisjr
nghiep's avatar
nghiep
79 posts
 
Even when it had a flat spot at the end of the ball bearing, you don't need to remove it. You can use diamond lapping compound to smooth out the flat spot. Then you can use a small teflon, nylon, or brass flat disc placing at the bottom of the bearing housing. Now you have the ball bearing flatted spot contacting the teflon disc as rotating (contacting) surfaces. My old VPI Scout non inverted bearing got a flat spot at the bottom and it still works fine.
eldartford
4,262 posts
 
Differential expansion coefficients of different materials is often used to assemble things like this. If you were to heat or cool the assembly the ball might just fall out. Sometimes during assembly one part is heated up and the other is cooled. This makes assembly easy, but disassembly is near-impossible.
ketchup
695 posts
 
Nghiep beat me to it. If Kwillisjr came back and said that the ball was worn, I was going to recommend resurfacing it in a similar manner. I just used 600 up to 2000 grit sandpaper to polish the end of my Delphi's motor armature/bearing to an killer finish. It was pretty worn but turned out very nice. There are some "after" pics of the bearing in my virtual system.
yioryos's avatar
yioryos
723 posts
 
I think I understand the situation,and if so then I say it is impossible to drill the ball out because the ball will spin around when the tip of the drill bit contacts it or soon after it bites on the ball.I say leave it alone.If you are firm about it just see a machinist to make a new one .Probably easier task!I've seen steel security bars that are hacksaw proof.How?The manufacturer places rods inside the steel tubing,any attempt to cut it through fails simply because as soon as the blade hits the rod inside the tube it makes it rotate and inposiible to run through the whole piece.Simple and intelligent solution.
Best of luck
George
kwillisjr OP
2 posts
 
Thanks for your responses. I actually have two platters and bearing assemblies at the moment. This is not the only table I've ever seen that uses a single ball in the end of the platter shaft. It is the only one I've ever seen that actually uses a second ball in the bottom of the bearing well as a thrust bearing. One of these bearing assemblies came from a table that was bought in the early seventies, used on weekends for a couple of years, and then left sitting in the intervening years. Because of the bearings just sitting there, both platter and thrust bearings developed flat spots. The other bearing assembly could possibly be polished out (and it sounds like that may be the preferred option). So, anyway, I'll think about it and see.
More to discover