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Wall thickness for bearing housing


Jan 21, 2019
Is there a rule of thumb for wall thickness for a spindle/axle housing? Is it based on width of bearing like a bolt to edge of plate or axle diameter?

I see pillow blocks with thin walls on top and lathe spindles with inches of metal around the the bearing. Crank shafts have bearings with a sliver of metal around the bearing?
Don't know of a rule of thumb, but I'm thinking at least two to three times the thickness of the race under the balls, or the cup thickness at centerline.
It's a good question, I've wondered the same myself from time to time. I'm sure there is an answer, and I'm also sure no two engineers will agree on exactly what it is. I have to admit...I tend to use the eyeball-test...if it looks too weak, it probably is.
Crank shafts have bearings with a sliver of metal around the bearing?
Yea, but they have a block holding it all together......... :D

If you are building something, the reason for asking the question.......????
Just look at what somebody else did and duplicate it or if you're worried make it a bit thicker.
Rule of thumb: Follow the Design engineering process.

1. Write the requirements. Loads, speeds, temp ranges, exposure to environment. (Rain, salt water, chemicals etc). Weight, cost. Accuracy of motion.
2. Make initial design. Analyze for forces, tolerances to see if it meets requirements.
3. Iterate design and analysis until requirements are met.
4. Make detailed design drawings of parts.
5. Fabricate prototype.
6. Test to see if it truly meets requirements.
7. Go cash your paycheck.
This is a tricky question when fitting unit bearings to old motorbike crankcases .........a small bearing with low load rating,or a bigger bearing requiring the case bearing bore to be increased ....how thick does the alloy case need to be to avoid cracking,or even total failure.
Sometimes, its just a one or few piece run that isn't worthy of days of simulation and analysis. It's needed now, and just has to work the first time. Hence, the wall thickness question.