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Shafts and bearings

I came to examine another piece of garage sale acquisition:

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The two pillow blocks are all part of a single casting which encloses two ball bearings. There is a 5/8" shaft which on either side is reduced to 1/2" and threaded 20 tpi, one side left and the other right handed. There is a pulley in the middle like in the picture and an old v-belt around it so someone had to have the shaft off in the past to put these on.

I can find no screws of any kind and cannot but conclude that the bearings are press-fit into the housing. Interestingly, the shaft has a 1/16" or so axial play within the race of the bearings but none when turning (there is no slipping in the races).

The whole thing looked useful when I saw it and for $5 it seemed a steal. Unfortunately, the right-hand end of the shaft has a minor bend in it. Also the v-belt will need replacing so I cannot see my way past having to disassemble the whole thing.

I have never taken ball bearings apart. I hit the Google and books yesterday and am comfortable with the principles but, as with anything, God is in the details:

1) Given the one piece construction, I shall have to hammer the shaft out of both bearings simultaneously. Is there a way to make sure that the shaft comes out rather than bearings with the shaft still attached? I can block up one of the inner races but not both at the same time.

2) OTOH getting the shaft and bearings out as one unit may be a better way. How does one make sure that this is what happens?

3) Any other helpful thoughts?
Reply to
Michael Koblic
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Michael

Absent some other disassembly method you will have to press the shaft. Pesss the small shaft end and support the bearing housing as necesssary. From prior experience I believe you will find the bearing to housing not as tight a fit as the shaft to bearing. There also might be shims for axial play involved. Buy new bearings before disassembly. I would straighten the shaft using my lathe and heat as needed.

Bob AZ

Reply to
Bob AZ

You have two pressed on shaft ends and two pressed in bearings. The fit on either the inner or outer press fit will be much easier than the other fit on the same end. Disassembly is the same: press from one end until the other end bearing comes free of the housing. If the bearing comes off the shaft easily, you are good, if not, put a collar on the now free end and press the other direction.

You may or may not be able to straighten the shaft enough to get it to run true. If you want to run buffing wheels, a bit of run out won't make any difference.

Do NOT try to run this as a gr> I came to examine another piece of garage sale acquisition:

Reply to
RoyJ

This is where I get confused: If I press the shaft and support the housing only I put a lot of strain on both bearings. If I understand you correctly this is where the "buying new bearings" comes in, i.e. there is no way to preserve the existing bearings?

Thanks.

Reply to
Michael Koblic

Michael, Try contacting one of these guys, they may have had to take one apart before.

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Good luck, Paul

Reply to
Paul

So if I understand correctly:

1) There is no way of predicting/ensuring which bearing pops first or even if it is the shaft coming out of the bearing or the bearing out of the housing 2) There is no way of protecting the other bearing, in fact both bearings may be wirte-offs at the end of the procedure

I have not quite decided what to do with this. Any future use is kind of predicated on ease or otherwise of disassembly/re-building etc. I even wondered if one wanted a true shaft one could true it up in the assembly itself (ruining the thread, naturally) by spinning the other end with a hand drill and making like a lathe on the end in question with some sort of makeshift tool post.

That I have no intention to do. However, if I could get a 5/8-11 thread on the end of the shaft somehow one could hook up one of the new cold-cutting saw blades on it and spin it at the appropriate speed (I could even make a guard for it :-). Just (for most part) idle thoughts...

Reply to
Michael Koblic

If you are primarily concerned about changing the belt, why not use a replacement with links?

Reply to
peter divergilio

Correct but most of these come out without too much effort, shouldn't hurt the bearings. If you have a small press, just ease them out. Hammering should be avoided but has been done a lot of times. Since the bearings are held in by the buffing wheels on each end, these are not pressed on with the same forces that you would see on a critical application eg rear axle shaft.

Michael Koblic wrote:

Reply to
RoyJ

Those arbors are handy to have around for various uses. Many of those were made with only bushing bearings, the deluxe ball bearing model is not all that common to find IME. Your housing has the extending tabs/slots to facilitate the installation of wheel guards and tool rests.

The bent shaft is only a problem if you need to mount something on that side, otherwise, you could add a shaft collar with a setscrew in it to prevent the shaft from walking.

Using an incorrectly applied force could break or damage the housing, making it a repair project, or just scrap. Using a couple of plates the same length as the distance between the bearings' inner races (or a length of pipe cut in half lengthwise) would support the bearing spacing while attempting to remove the shaft with cautiously applied force, if the shaft is not floating.

WB ......... metalworking projects

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Reply to
Wild_Bill

You can disregard part or all of the earlier post, now that I discovered that the center section of the shaft is 5/8", and the beraing IDs would be

1/2".

WB ......... metalworking projects

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Reply to
Wild_Bill

Actually, I do not think they are. Looking at it closely the 5/8 to 1/2 shoulder occurs at the bearing and the inner race seems to be 5/8".

Reply to
Michael Koblic

This is impressive! How on earth did you get to these pictures?

Reply to
Michael Koblic

That and the bent shaft...

Reply to
Michael Koblic

The bearings are deeply recessed on the inside and although I have not tried it I have thought of this solution. I did not think, however, that I shall be able to fit the supports sufficiently tightly between the bearings into the recesses. Maybe if I cut a pipe with inner diameter of 5/8" both

*lengthwise* and *crosswise" then I could get each quarter in, position it and stabilize it, somehow it might support both inner races.

That's why I love this group. You guys not only give me solutions, you make me think about them...

Reply to
Michael Koblic

Most ball bearings come in metric sizes. What is the number on the bearing?

Dan

Reply to
dcaster

Do a Google search for general +milwaukee +"est 1930" Paul

Reply to
Paul

There is always a better way :-) BTW I contacted both guys who were very quick to respond but neither has taken the piece apart. The more I look at it the more I think it should be left well alone!

Reply to
Michael Koblic

Most ball bearings come in metric sizes. What is the number on the bearing?

6202Z Asahi Japan
Reply to
Michael Koblic

A 6202Z bearing is a common metric deep groove ball bearing with a metal shield on one side. ( the Z indicates a shield on one side and a ZZ after the number indicates shields on both sides . An R indicates a polymer seal and RR indicates sealed both sides) It has an I.D.of 15 millimetres,an O.D. of 32 millimetres and a thickness of

9 millimetres. It should be readily available at any reasonably good industrial supplier
Reply to
Grumpy

That's the 6002. The 6202 is 15mm id x 35mm od x 11mm width. I just got done ordering one of each from Motion 2 days ago. I had to design a little stub shaft to replace the Parr reactor seal on a lab reactor. The Parr design depends on only one bearing, and runs on an o-ring belt. I need to switch to an HTD belt, so I needed more side load capability.

Pete Keillor

Reply to
Pete Keillor

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