pic: 4587-Sheet Metal Chassis V.2

[Adrian Clark]

Originally Posted by ekapalka

I don't mean to change the subject, but this information has highlighted a problem for me. I've been designing a gearbox for quite some time, and I've clearly been making a huge mistake with the hole sizes for the bearings I'm using. If an AndyMark flange bearing has an outer diameter is 1 inch, in accordance with this, the hole diameter for the bearing should be 1.0005 in? That seems really close. Could you just verify before I go back and change everything? Thanks

Most teams use interference fits for their bearings. Doing so is an easy way to retain the bearing and accurately locate it. For a good fit, as tim-tim suggested, you want about .5 thou interference. This means you should make your bearing bore .5 thou smaller than the diameter of the bearing.

However, there is no universal rule for bearing fits. What size you make the hole relative to the bearing OD depends on how tightly do want to retain the bearing if you want to retain it all, the size of the bearing, and what method you're using to make the bearing bore. There's a lot of info on this subject here on CD, the thread tim-tim linked to is a good place to start.

-Adrian