3D Printing 3D Prints and 1010 Rail

[boatgeek]

I have a spool-ish oddroc that I'm working on, and it would be pretty convenient to have the whole things nest around a 1010 rail for launching rather than building in rail buttons or similar. My initial thought is to have a 26.5 mm square with a 2mm wall around the 25.4 mm square rail. I was a little concerned about strength and whether the rocket would bind on the rail. Does anyone have experience with this approach?

Thanks!

 

[Kelly]

I would flare the top sides of the square, so that they don't catch on the rail when the rocket cocks a little. Make it look a bit like a trumpet horn, facing up.
How far from the line of thrust will the rail be? I can see it binding for some combinations of a short square, and a significant offset from thrust.
Seems like it could be made sufficiently strong, though.

 

[boatgeek]

I would flare the top sides of the square, so that they don't catch on the rail when the rocket cocks a little. Make it look a bit like a trumpet horn, facing up.
How far from the line of thrust will the rail be? I can see it binding for some combinations of a short square, and a significant offset from thrust.
Seems like it could be made sufficiently strong, though.

I was planning on filleting the top corner maybe 1.5mm, but I could flare it a little more without too much trouble. The line of thrust is 46mm from the center of the square, and the spool is 90mm tall. The tube for the rail is the full height of the spool less any flare/fillets at the top and bottom.

 

[Kelly]

Never done it before, but just eyeballing it, that feels like it would work fine. A fillet/chamfer is probably sufficient.