Styrene Rod Shear Pins

Hi folks.
I've been checking out ROL Info Central for shear pin details. It recommends 1.5mm square Styrene rods and the number required.
All the same I'll be ground testing first.. :-)
Is there a reason for using square rods instead of round or is there no difference? Do they 'SHEAR' better?
Timer & Altimeter has landed and I'm starting to organise my Duel Deploy Beast. 2.14in. 38mm MMT. Well........maybe it's a mouse........but it's a nasty little sucker :-)
Cheers, Clint
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I use round. Round works great because you can find small brass tubing at hobby / craft stores that works as a sheath, protecting the plastic nosecone and paper body tube from deforming over time when shearing the shear pins.
I think the advantage of square is that you could make the holes slightly smaller than the squares, and the pins would stay in welll. With round, you have to get the holes exactly the right size to get a snug fit, but still be able to get the rod into the hole.
-- David

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I also use the round styrene rod. I just used CA glue to reinforce the hole in the body tube and a glob of epoxy in side the nose cone. If the hole starts to enlarge I just touch it up with CA.
John
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I usually use 4-40 nylon screws. But I have used styrene rods. I take about 1/4" to 3/8" length and then squeeze one end with a pair of needle nose pliers. Insert the rods with the squeezed flat section last. The flat section will provide a snug fit to hold them in place. Works great.
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On Fri, 27 May 2005 19:18:55 +1000, "CJC"

I don't know why they say that which doesn't mean it doesn't work. I use nylon 2-56 screws.
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