SS 3/16" Launch Rod Suggestions

[Faroutspacenut]

Related to my earlier post here: https://www.rocketryforum.com/threa...aunch-controller-options.148625/#post-1825108

This weekend I put together a 6-bank sawhorse launch rack (i'll post a build thread on that eventually - really pleased with how it turned out) but in addition to that, I'm putting together some single launch pads to accommodate longer rods.

I bought some 304SS 6' rods from McMaster Carr for these. The 1/4 rod is plenty stiff, but the 3/16 rod not so much. I'll probably shorten it some (not sure I'll need all 6') but I'm worried about rod whip.

Here's what I got: https://www.mcmaster.com/89535k84

Any suggestions on a stiffer 3/16" launch rod? Ideally one that won't break the bank?

I have a mix of (3 foot) 1/8" and 3/16" rods on the 6 pad rack, but for some of my rockets I think I need a little more length than that.

 

[manixFan]

Maybe it was just a bad observation but it seemed to me the stainless steel rods I bought were springier than the cheaper regular steel versions. I had some steel rods I had bought at Home Depot and then replaced them with SS ones from Grainer. I ended up having to shorten the SS ones to try and eliminate some of the rod whip I was seeing from them. But they do clean up easier.

Maybe somebody who knows metals will chime in and help out.


Tony

 

[rharshberger]

Stainless rods are not as stiff as carbon steel rods, and carbon rods are even less stiff than drill rod which is a carbon tool steel grade rod and can be hardened (McMaster-Carr carries drill rod). The stiffest launch rods will be hardened carbon steel music wire rods like K&S Metals sells at your LHS or online however they only come in 36" lengths iirc. The advantage of stainless steel is in its ease of maintenance not its stiffness, though some grades of stainless are stiffer than others iirc.

Edit: MC does carry multipurpose O1 drill rods in up to 6' lengths however they are annealed and would need hardening to improve stiffness, not necessarily and easy task without proper equipment (to harden a long rod without a furnace is tough).

 

[Faroutspacenut]

Following up here for completeness and for anyone searching this thread in the future. Found 4 foot long 3/16" rods at Home Depot - they look to be carbon steel. Pretty stiff - I can hold them by the very end horizontally and only get a tiny bit of bow. Still a bit shorter than I'd want, but most of the big things I'd be flying off rods have 1/4" lugs anyway.