bearings help.. I lost a few..plus a drill press runout question

[cuemaker]

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]

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]

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]

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]

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]

I believe Mcmaster sells individual balls for bearings.

[SGW]

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]

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]

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]

Better to have lost a few balls than a bunch of marbles. Sorry couldn't resist.

[cuemaker]

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]

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]

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]

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]

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.




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




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



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.