Concrete mounted 1/4" tube bearing.

[stu]

Problem:

Using a 1/4-20 SS screw as a hinge pin for a plywood hurricane shutter, what can I use beyond a 1/4" hole in a concrete block?

It needs to rotate 90* max.

Would a 1/4" lag shield provide a sturdy 'bearing' surface for a machine screw?

Any other ideas for inserting a tube bearing into a concrete block?

[C & E]

I'm going to assume that the concrete block is a solid sill on the bottom and a lintle on top. If so and the hole is a couple inches back from the edge it should be OK. You could also drill a hole and drive in a lead anchor using that as a sleeve of sorts. Or, you could do a large lead anchor and sink a machine screw (hex head) into it, having previously drilled a hole (5/16") to fit the 1/4-20 SS screw that you mentioned. Of coures, this wold take a aizeable hole and may not leave you with sufficient concrete material. I'm also supposing that you plan to allow clearance in that you will feed in the top screw into the sleeve and they position and lower the bottom screw into its receptical. Should work.