What does the ABEC rating actually mean?
ABEC stands for Annular Bearing Engineering Committee of the AFBMA(Anti-Friction Bearing Manufacturers Association). The ABEC grades are a set of standards for the manufacturing tolerances of bearings. All quality manufacturers around the world, manufacture to at least the ABEC 1 standard.
Is there a lower grade than ABEC 1?
There is no grade lower than ABEC 1, but bearing manufacturers are "NOT REQUIRED" to meet any ABEC standard. Therefore, be very careful of bearing manufacturers that do not give any data. Only purchase bearing brands that are well known & come with data!
Are there other standards for measuring bearing precision?
Yes. There is the ISO(International Standards Organization) standard.
What is the purpose of high precision bearings?
High precision bearings are designed to allow high precision machinery to operate smoother with less noise & sometimes at higher speeds. High precision bearings do not guarantee operation without failure. The loads applied, lubrication amounts & type, mounting, etc. will determine limiting speeds. Consider that a standard 15 MM, inside diameter, ABEC 1 bearing has a limiting speed of 44,000 RPM, if the lubricant is 20 wt oil.
Do high precision bearings guarantee greater engine RPMs?
No. The most important factor in attempting to get greater speed from any bearing, is how the inner & outer race of the bearing is mounted. Even if the bearing is an ABEC 7, with a fancy machined phenolic cage, its operation will be greatly compromised unless the mounting is correct! However, you will have spent a great deal of money un-necessarily in acquiring the high precision bearing.
What ABEC number would be best for model engine use?
IMHO no bearing higher than ABEC 3 precision is necessary in our engines. Higher grades will only cost more money & will not give any increase in performance.
What are the factors covered by ABEC grades?
There are several things such as the roundness of the balls, eccentricity of the bearing tracks, bore ID, bearing OD, surface roughness, etc.
Does the ABEC grade effect the radial play of a bearing?
No. Bearing radial play or clearance amounts are desiginated with the letters L,N,P,K,T, or C1,C2,C3,C4,C5. If K(.0008" to .0011") or C4(.0007" to .0013"), ABEC 1 to 3 bearings are mounted correctly, with the correct amount of interference fit on the ID & OD, you will be very surprised how long & how fast the bearings will run without failures or abnormal wear. Be aware that any nitro or alcohol powered engines need to have all amounts of moisture removed immediately after running!!
Jim Allen
