I have a small cantilevered mounted bearing housing that rotates about it's longitudinal axis. The bearing housing is loaded perpendicular to it's rotation axis, as is usually the case.

I am using a standard hardened steel dowel pin as the bearing shaft. The dowel pin is just pressed into a steel support, and then the bearing housing is installed onto the dowel pin / shaft. The steel support can slide up or down on two dowel pins and can be adjusted and locked as needed. This allows for adjustment of the vertical location of the bearing housing.

The bearing housing shaft is pressed in-between two other dowel pins that the steel support slides on, which have a very close tolerance slide fit. I think I should probably use a light press on the bearing shaft, so that the press of the bearing shaft does not affect the hole size of the slide fit dowel holes located on each side of the bearing shaft.

The bearing housing is oscillated manually by hand and the device is always used at room temperature. There are no vibrations present since the device moves so slow, but there are reversing loads on the bearing housing, and cyclic loading with variable loads.

I was hoping to use a light press fit for the dowel of 0.0001" minimum to 0.0012" maximum.

I have a picture of the housing arrangement at the following link. It is "housing # 2" i.e., the one shown on the left, that I am using...

https://www.ice9.zoomshare.com/

1. Can anyone please give me a recommendation for a minimum amount of press fit that I can probably get away with for the bearing shaft ? Is 0.0001" minimum to 0.0012" maximum probably OK ?

2. Due to the way the housing is loaded, I think for the most part the load would not tend to pull the dowel / shaft out of the support and would actually make it bind in the support ? However, there still may be some tendency for the housing load to pull the dowel out of the support. Is there a way to calculate or get a close estimate how much axial force will be applied to the 3/8" OD shaft due to the housing load ?

3. Can anyone please tell me the method or formula for calculating how much axial force it takes to pull the dowel out of the hole, based on the amount of interference of the press fit ? The dowel and support are both steel.

4. Do I need to be concerned with changes in the minimum interference of the press fit, just due to normal changes in ambient air temperature ? The device is always used a room temperature.

Thanks for your help.