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View Full Version : Maximum compressive load of a 608ZZ skate bearing?



DICKEYBIRD
09-06-2011, 11:55 AM
Our new work firewall prevents me from getting onto many websites (Yay, I can get on here though!) I'm trying to find out if I'm wasting my time transferring the inline skate bearings onto the new aluminum wheels I'm making for my metal storage drawer.

One of the urethane skate wheels totally collapsed after loading the drawer to about 3/4 of it's intended capacity. The harder plastic hub that the outer wheel is bonded to shattered under the load. I suspect that all 6 wheels aren't contacting the floor equally as well since no concrete floor is really flat.

Anyhoo, anybody have access to a chart showing how much load a typical 608ZZ (stamped ABEC 1) inline skate wheel bearing can withstand?

Weston Bye
09-06-2011, 12:09 PM
I looked up the garden variety 608 (don't know the significance of the ZZ suffix) bearing in McMaster-Carr. Dynamic load capacity was listed as 730lbs.

Dave S.
09-06-2011, 12:15 PM
If you can get to this website. This would help.

http://www.vxb.com/page/bearings/PROD/SB/608ZZ10

Dave

10 Bearings 608ZZ are made of Carbon Steel, 608Zz bearings are closed with metal shields to protect the bearing from dust or any possible contamination,608ZZ Bearings are self lubricated bearings (bearings are already greased), 608ZZ is one of the most common widely used bearing, we always suggest mechanical engineers to use 608ZZ in their designs, 608ZZ is economic and standard.
•Item: Radial bearings 608ZZ (608Z)
•Type: Metal shielded Deep groove ball bearings 608ZZ
•Material: Carbon Steel
•Closures: Metal Shields
•Dimensions: 8*22*7 mm/Metric
•ID (inner diameter)/Bore=8mm
•OD (outer diameter)=22mm
•Width/Height/thickness=7mm
•608ZZ Bearing Size: 8mm x 22mm x 7mm 608Z
•Quantity: 10 Bearings
•Dynamic load rating Cr: 3,300 N
•Static load rating Cor: 1,350 N
•Limiting Speed: ◦Grease Lubrication: 34,000 RPM

•Packing: 10 Bearings in platic tube
•Equal: 608-2Z & 608-ZZ
•608ZZ Applications: Skateboards, Roller Blade, Inline Skating, scooter, Rollerblade
•NMB: R-2280ZZ = 608Z
•Euqal: 608-2Z

DICKEYBIRD
09-06-2011, 01:10 PM
Thanks Wes & Dave, that helps a lot! VXB was one of the 1st sites I tried but it was blocked. I'll have to wait until I get home tonight.

Evan
09-06-2011, 03:47 PM
Cut the dynamic load value in half for static or slow moving loads.

DICKEYBIRD
09-06-2011, 04:56 PM
Thanks Evan; the static value Wes listed from MSC was 1350 Newtons which is a bit over 300 lbs so I took a pessimistic outlook due to the bearings being used El Cheapos and figured about 200 lbs per bearing or 400 per wheel. I figure at least 3 of the 6 wheels should be touching the floor at once (another pessimistic SWAG calculation) so it looks good enough to give it a try and start making some swarf tonight.

If I start hearing cracking noises after it's loaded up, I'll have to go to plan B (for bronze.) :)