Ball/roller bearing runout measurement?

Lets say that desired precision bearings are not available or are totally cost prohibitive.

I get the general idea like here:
How to Measure Bearing Tolerances
Micrometer dial indicator should be good to ABEC-7 at least.

Preload the bearing some way or another?

Does the bearing grease need to be washed out and bearing lubricated with thin oil?

MattiJ said:

Micrometer dial indicator should be good to ABEC-7 at least.

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Not even close! You might get by with using air gages to check bore, or an indicating mike to check OD, but radial and axial runnout are a different story. 30 years ago, when I was in automotive, we had $1M USD in gaging to check CV joints. Universal joints were easier, trunion diameter was +-0.0001".
JR

Assembled radial run out in precision class Timkens is in tenths and part of tenths

Note the lowest precision class 3 has but 20% of the class 2 gear box bearing assembled runout

JRIowa said:

Not even close! You might get by with using air gages to check bore, or an indicating mike to check OD, but radial and axial runnout are a different story. 30 years ago, when I was in automotive, we had $1M USD in gaging to check CV joints. Universal joints were easier, trunion diameter was +-0.0001".
JR

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4 micrometers runout for medium sized abec-7 bearing?

Bearing Tolerances and Precision Levels | AST Bearings

I believe with the modern methods the bearing manufacturers use when packing "precision" Angular contact bearings that I replace in spindles, they do not recommend washing them out . When I install new bearings that come in a plastic bag and have a lubricant in the bearing and bag. I take them out of the bag, grease them and install them. I have been told that the chances of contamination by washing them is likely to happen and not do it. I have washed good used bearings I repacked in a clean tin coffee can and unused lacquer thinner.

When installing working with bearings I clean everything, tools, bench, on a bench near the dirty shop. I never had a clean room and also never had a bearing failure. I use Mobil # 28 or 32 synthetic Red grease I buy in a 1 pound can. I always used a 30 % fill of the bearings. I used to dip a finger in the can and press it into the races. Always keep can closed when not dipping. As I said I never had issues. I know some will say that is the wrong way, but it worked for me.

I found this manual on Precision bearings you should read. It mentions installing the * on the bearing 180 degree's to the shaft TIR. I never was concerned with the size application as I removed old bearings and replaced with the same number bearing. I did chrome a few shafts and had to regrind, but I would call my bearing distributor to get the factory spec. Also before chroming I have the grinding company mic the shafts so we knew the size. Most grind shops have 3 anvil pressure mic's.

https://www.schaeffler.com/remoteme...andling_mounting_precision_bearings_us_en.pdf

johnoder said:

Assembled radial run out in precision class Timkens is in tenths and part of tenths.

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As of a couple of years ago, the accurate Timkens came from England, had to be special ordered with a 6 month lead time, and had a pretty hefty minimum. We were paying several thousand dollars a set.

At the time they were talking about not doing it at all anymore

Thanks Richard, that's a nice and informative writeup on bearings.

BTW, isn't the rule of thumb that the checking instrument be 10 times more sensitive than the spec? So a 0.00005" spec on ABEC 9 bearings needs a 0.000005" measuring device? 5 millionths of an inch. Or 0.2 micrometers?

bosleyjr said:

BTW, isn't the rule of thumb that the checking instrument be 10 times more sensitive than the spec?

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Only in cases where you don't want to be bothered with calibration or error correction.

bosleyjr said:

Thanks Richard, that's a nice and informative writeup on bearings.

BTW, isn't the rule of thumb that the checking instrument be 10 times more sensitive than the spec? So a 0.00005" spec on ABEC 9 bearings needs a 0.000005" measuring device? 5 millionths of an inch. Or 0.2 micrometers?

Click to expand...

1:10 rule is reasonable starting point. Note here that you need high resolution but not much accuracy. 5% error on runout measurement is neglible whereas diameters are measured in ~~0.0001% or so.

Non-repertive runout is different animal and to measure that it would take orders of magnitude more accurate instruments.

Bearings are an assembly. Inner, outer and balls/rollers.
Nothing irks me more than to see "... is tested by measuring all points on one circle ... during one revolution.
The system does not cycle in one revolution. This is a misleading measurement.
Mark your ball cage inner and outer and rotate one rev.
How many revs until those marks realign? This simple test is a kind of eye opener and yet missed by many.

If you work with profile grinders do you add a 360 turn once a while in a cycle to get near home. A problem that may be compounded if the front and rear are different size and cycles.
You don't have a lvdt on the race and don't really care about a inner or outer. The rotating system which is your bearing counts.
Depends on what you need to hold.
Bob

Hello,

I found information about the roller bearings measurement here.
Taylor Hobson PGI NOVUS along with Metrology 4.0 software can auto-detecting the roller bearings edge at the start and end of the roller and it provides the analysis of roughness, wall thickness, dimension, and waviness, etc.

In my opinion, Hands and under fingernails should be spot clean and one’s clothes should be clean so not contaminated with shop grit - bearing work done out of the shop in a cleaner room, a fresh cleaned and dried then with a clean towel over Stainless Steel saucepan or pot should be used because they have no cavities, are easy to clean and do not oxide like/as much as aluminum, steel or iron pans - fresh/new solvent from a can just-for-bearings so the apprentice has not contaminated it with touch pouring onto a dirty rag - the bearing should be sloshed washed and picked clean if picking is needed - they should not set in solvent overnight because some corrosion may occur - *they should not be spun with the air hose because fast spinning and crashing balls or rollers is not good - after solvent they should be dipped in spindle oil and tilted this way and that so oil is dripped out - then set on and between washed towels overnight/or a few hours to dry – ¼ to 1/3 greased with bearings-only grease so the apprentice has not stuck his dirty fingers into the can. Actually, good to use individual grease or a small grease package or can so less chance of it getting dirty or contaminated over time - the bearing grease container should never be left open - Packed bearings should be kept under cover until used - non precision bearings should be turned under a tenths or micron indicator to see and mark the high or acentric is assembled at the same mark so the shaft goes lope de lop now wobble-wobble end to end. precision bearings should have acentric marks on the same line. Bearings set in double should be felt to see a little pre-load is felt – precision bearing are preload set for a given RPM or enough load to get them to about 130 to 160 degrees F because many greases degrade or fail at going to and over 200 degrees F...use some care and thought to see the fit to bore and shaft and method of assembly such as hammer whacking and the like does not damage them - often they need be made tight and then backed off to proper pre-load set, if they are not seated the pre-load may change - spindle bearings are direction designed so good to look at shoulder to see they are placed right.
Any machine that has set for a time the spindle should be hand turned/spun a few times and then slow jog started a few times. all high speed 3400 or so plus should be jogged ever cold start. A spindle that feels not-smooth turned by hand will/may not last very long.

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