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View Full Version : bearings help.. I lost a few..plus a drill press runout question



cuemaker
03-27-2011, 12:13 AM
I am trying to fix the run out in my drill press and I lost like 6 of the damn balls...

My 1st thought was to replace the bearings in general.. but I cant.. I have weird measurements...

Its an axial bearing, no cage to hold the balls...

Anyways the size's.. OD is the same for both of the plates.... .9965 but the ID is different for the top and the bottom.. One is .4990 and the other is .5335

Its not a wear issue as there is a larger bearing lower in the assemble with the same thing....This drill press has 4 bearings..2 for the down thrust (axial) and 2 for side to side (thrust) although 1 of the thrust bears is very high up for the transmission of power area....

Should I just replace the balls?? If so what kind? The balls measured .1210

The shaft which runs through the whole assembly ran very straight in my lathe.. yet wobbles in the press.. not sure why yet...

J Tiers
03-27-2011, 12:46 AM
Even axial (thrust) bearings *usually* have some sort of cage. for ball type (many are roller) that is often a bronze ring where the balls are loosely staked in place.

*Usually* (no pics???) the bearing consists of the bronze ring with balls and two hardened and ground flat washers, and there is nobody watching you to make sure you don't use a ball ring from some OTHER bearing..... if you can find one that fits.

In some cases with old machines, the balls may be loose and run in a groove. I have a small DP with what I presume is that setup, I have avoided taking it apart.

You will want to have all the balls the same size, but there is probably a bit of allowance on absolute diameter. However, they are not usually sold in matched sets......

If you can find a "donor" ball bearing with sufficiently similar sized balls, maybe you can cut it (or them) apart and extract the balls you need.

You lost 6, how many were there total?

cuemaker
03-27-2011, 01:53 AM
Its an old DP.. Leland Gifford high speed sensitive DP... No cages.. just the 2 washers with grooves...They do have a shield that covers them

The number of balls had to be about 18, I would say 6 was about a 1/3 of them..They were all touching each other..

I think I can buy the balls....

Cant use one ball from the others.. the others are much bigger

RichardG
03-27-2011, 02:16 AM
Hi,
I went to the local bike shop they carry a bunch of different size ball bearings only cost about a buck for the 7 or 8 I needed. Might be worth a try.

Richard

form_change
03-27-2011, 04:26 AM
A bearing supply shop should be able to sell you loose balls. I'd replace the whole lot as those that are in there could be worn anyway and it's easier to make sure they are all the same size if they are all the same batch.

Try putting the shaft on some vee blocks (a pair of small ball bearings is even better) and rotate it with a dial indicator in various places to check whether there is a bow in the shaft. If you can remove the chuck check the JT as well - it might have had a knock somewhere. If that is all good it could be the chuck. I had an Albrecht once that had a wobble to it as a previous owner had allowed it to spin on the JT. New arbor and socket and the problem was fixed.

Michael

Boostinjdm
03-27-2011, 05:19 AM
I believe Mcmaster sells individual balls for bearings.

SGW
03-27-2011, 06:54 AM
Lots of bearings are made to metric dimensions, although if you convert your measurements to mm they all seem a bit large -- slightly larger than an even number of mm, or half mm.

How confident are you in your measurements? Do you have some kind of measurement standard or something like a dowel pin or drill shank you can check against? (A dowel pin will probably be 0.0002" over nominal size and a drill shank maybe 0.0005" to 0.001" under.)

duckman
03-27-2011, 08:18 AM
Just remember that when you reinstall the races that the the side with the big hole is stationary and the other one keeps the shaft centered, you would not believe how times I've repaired a machine with the bearings installed backwards and it usually wears a groove in the shaft.

aboard_epsilon
03-27-2011, 08:19 AM
sometimes on the side of the quill there is a screw that bears against the quill to take up the slop .
least in cheap chinky ones there is .
all the best.markj

duckman
03-27-2011, 08:32 AM
Better to have lost a few balls than a bunch of marbles. Sorry couldn't resist.:rolleyes:

cuemaker
03-27-2011, 11:34 AM
Just remember that when you reinstall the races that the the side with the big hole is stationary and the other one keeps the shaft centered, you would not believe how times I've repaired a machine with the bearings installed backwards and it usually wears a groove in the shaft.


Excellent advice....

Pictures coming....

I found these balls....
http://cgi.ebay.com/Ten-3-16-Silicon-Nitride-ceramic-Si3N4-bearing-balls-/380211555298?pt=LH_DefaultDomain_0&hash=item58865febe2#ht_2641wt_905


$1 dollar a ball plus shipping seems extreme... but they seem interesting..

gambler
03-27-2011, 11:41 AM
sometimes on the side of the quill there is a screw that bears against the quill to take up the slop .
least in cheap CHINESE ones there is .
all the best.markj

fixed it for you.:)

justanengineer
03-27-2011, 11:51 AM
When I restored my benchtop camelback Buffalo Forge 10 inch dp I ran into the same problem. Mine havent been there since Ive owned the machine however, just races. I looked into buying bearings but the hardware store/bike shop variety werent quite the same. I suspect they were all metric, but being an early teens machine, mine shouldve been all standard. Eventually I gave up on those bearings bc I decided the races were a bit too worn for my taste. One day when I get some gumption I will probably just turn some new races to fit whatever balls I buy. $1/ball sounds high until you go to a bearing distributor and they the smallest box they have is 5000.

rohart
03-27-2011, 12:19 PM
The rule for loose balls is to fill the race confortably (ie with a little gap) and then remove one ball. That's definitely the rule for slow stuff, like m/cycle head bearings and bikes, but I would't be so confident about high speed spindles.

If you're getting them from a lower grade source, get three times as many as you need and select for size yourself.

cuemaker
03-27-2011, 12:24 PM
OK, picture set up......

1st picture is the very bottom...what is held in the vice is the JT section for the chuck....I did not lose any of these balls... They measure .184 and they were packed touching each other.

http://i201.photobucket.com/albums/aa129/xringx/DSCF0017.jpg


2nd picture shows what sits on top of the bearing and is the shaft that moved the quill up and down.

http://i201.photobucket.com/albums/aa129/xringx/DSCF0018.jpg


In the bottom of what i am holding is a pressed in bearing for radial load

http://i201.photobucket.com/albums/aa129/xringx/DSCF0020.jpg

This picture shows the bearings that fell.. They measure just .1210 in diameter. They sit ontop of the quill. On top of the bearing are 2 nuts that thread on to the (shaft? quill?) the part that the chuck attaches to and runs through the center of everything.

http://i201.photobucket.com/albums/aa129/xringx/DSCF0019.jpg

cuemaker
03-27-2011, 12:25 PM
And a picture of the DP in general. ooops, thats an old one... I have since moved the motor down to the base and add a VFD...

http://i201.photobucket.com/albums/aa129/xringx/DSCN2146.jpg

Carld
03-27-2011, 12:44 PM
So, since you didn't need any balls for the bottom bearing how did you use the .187" balls in the race that had the .1210" balls in it?

Arthur.Marks
03-27-2011, 12:50 PM
Forgive me if this was mentioned before---I haven't read the full thread. That bearing will still work missing three balls. It just would have a slightly lower thrust rating due to less surface area. In practical use, though, I doubt it would make any difference.

cuemaker
03-27-2011, 02:06 PM
So, since you didn't need any balls for the bottom bearing how did you use the .187" balls in the race that had the .1210" balls in it?

I am not sure I understand...

The picture with the bigger balls .187 has some not in the the picture.. They fell out, I picked them up and put them in a cup...

My pictures were taken for me to show what goes where in what order during disassembly... Not so much for illustration...

McMaster sells bearings by the 100 pack...

Now to just find the source of the wobble..

Carld
03-27-2011, 04:01 PM
Well, I am confused too. In one photo you said, "These are the bearings that fell and they are .1210". Then in another photo you said, "This is the other bearing and I didn't loose any balls, they are .184".

So I am thinking if you didn't loose any .184" balls but you lost several .1210" balls and bought new .187" balls, then how are you going to put the new .187" balls in with the .1210" balls and have it work.

cuemaker
03-27-2011, 04:54 PM
carld.. I get where I lost you... my bad....

The .184 are in the picture too... I took more photos..

Here are just the .184's.. I have all of them...you can see the gap

http://i201.photobucket.com/albums/aa129/xringx/DSCF0021.jpg

Here are the .1210 I am missing a few... They are so much smaller, but you cant tell in the pic...

http://i201.photobucket.com/albums/aa129/xringx/DSCF0026.jpg

Alistair Hosie
03-27-2011, 05:12 PM
Hi without suggesting putting you to unecessary expense why not just buy a whole ne bearing a new one might be better in the long run.Of course I say that thinking that this might cost a few bucks but if it costs big money then of couse get new balls for the bearing/ best of luck Alistair

Black_Moons
03-27-2011, 06:12 PM
I wonder, Are those undersized 1/8", (0.125) or oversized 3mm (0.121 = 3.07mm)

cuemaker
03-27-2011, 06:15 PM
I am searching what bearing catalogs I can... Cant find what I want... The DP is certianly worth replacing all the bearings...

But when I read through Timkin and the like... I can find any with a ID of .75.. Let alone the smaller one.... They all are much bigger

I will call a couple of bearing places on Monday.. see what they can find for me..

rohart
03-27-2011, 06:45 PM
I don't know where you're getting .75 from.

The larger bearings (.187) are 3/16 and the smaller (.121) are 1/8, as Black suggested. No way that old DP will use metric, unless it arrived off a North Sea coaster.

A cycle shop will have the larger, and may well have the smaller.

However, the larger may not be shot, and the smaller are under less stress, being at the top of the quill. You could get away with just replacing the smaller ones.

With that kind of bearing, a marginal size difference of ball will not affect wobble. You may get wobble if the profile of the races has changed to the extent that the angled portion has totally worn away, so the radius of the contact patch is the same as the balls. The races rely on the radius of the contact path being larger that the radius of the balls, so that as you tighten the nuts there is only one place for the shaft to sit.

Best to have a good look at the races. I'm sure you could get complete bearing replacements, or if not then replacements with the ID larger and the OD smaller, leaving yoiu to machine up extra collars.

Carld
03-27-2011, 07:05 PM
You could probably use .125" if you replace all of them but the 3mm may be closer to size. It don't matter if you use Imperial or Metric sizes as long as they are close to what you need.

Boostinjdm
03-27-2011, 07:59 PM
McMaster sells bearings by the 100 pack...



I don't see the problem. I looked at 1/8" balls for $2.82 per 100 and 3mm balls for $6.05 per 100.
Pick a size and order them. Throw out the rest or save them for another project.

cuemaker
03-27-2011, 09:50 PM
No, not replacing the balls.. thats easy.. found them at mcmaster carr..

I am thinking about replacing the hardened washers too...On the 3/16 ones, the washers with the grooves show wear... its got a pretty roughed up surface.. Same thing for the bottom grove in the 1/8 washer..

The .75 is the ID for one washer of the 3/16 ball bearings (the other ID for the mating top washer is .860) and the ID for the 1/8 bearings is .4995 (with the top mating washer ID of .5335)

But once I get the bearing, I can turn the ID bigger on one of the washers to match

B Sutherland
03-28-2011, 11:01 AM
Take your bearing to your nearest bearing supplier that you deal with and get them to help x-ref it. The pictures you posted are showing a thrust bearing and they come as a unit.

Ed P
03-28-2011, 03:53 PM
Might be worth trying these people:

http://www.obsolete-bearings.com/

Ed P

vpt
03-28-2011, 07:45 PM
I went threw the same deal when I was "rebuiding" a old drill press I got. I was able to find the exact balls I needed on ebay and even had a choice of steel, stainless, carbon, chromed, etc.

http://bbs.homeshopmachinist.net/showthread.php?t=44285&page=2