Linear sliding shaft with bushing

[reconvolution]

Colleagues,

I need advice about a linear sliding shaft with bushing. This is a type of thing I haven’t designed before. The sole purpose of these shafts is to prevent rotation of one flat part against another. Both parts are flat plates, parallel to each-other. Plates are made of delrin. There are 3 parallel sliding shafts between them.

Shaft diameter: 4 to 6mm,
Travel: 25mm
Sliding is not too frequent: about 10 times per hour
Radial loads on the shafts are small

At the moment, I’m thinking of using a bushing like McMaster 7815K11 and shaft like McMaster 1257K113.

Is this a viable approach?
Is this an overkill? What are the arguments against just drilling a hole in a delrin part and calling that a bushing?
How would one secure the bushing? The bushing on McMaster has a small flange, and I can’t drill mounting holes in it.

Sorry, if the description is inadequate. I can add more details; just ask.

Any suggestion, insight or reference is really appreciated!

- Nick

 

[asimpson]

Biggest problem I would see is binding, that is if movement of plates not maintained parallel shafts will wedge in bore and lock in place. Solution to this is deeper bore in sliding member, shafts closer together, bigger clearance between shaft and bore, compliant bushings,

http://www.igus.com/wpck/default.aspx?pagename=drylin_r

http://www.pbclinear.com/Round-Shaft-Technology---Linear-Bearings--Linear-Guides

For low duty speed and accuracy using Delrin on its own would be fine. I would bore all parts together to ensure concentricity and parallelism. I would make fixed bore as deep as possible (x4 dia) and clamp shafts in place. I would make shaft size as big as possible. 6mm sounds pretty small. Any bending and it wont work.