brentius
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Hi, I was just wondering if theoretically screws could be used in situ of rail buttons? I already have my buttons installed, it's just that this thought randomly came into my head. Has anyone tried this before?
Rail Button Alternatives
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While it might work for a little while, the screw heads are going to gall the rail and ruin it over time.
-Kevin
-Kevin
https://images.app.goo.gl/hdfD11sSRjFGVDGGA
I bought a bag of these a few years ago.
I would not run just a metal screw in a rail, I could see a properly sized nylon screw for low power, make it replaceable.
I bought a bag of these a few years ago.
I would not run just a metal screw in a rail, I could see a properly sized nylon screw for low power, make it replaceable.
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lr64
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Wouldn't that depend on the material and/or finish of the screws? Alternatively, one could use a couple of plastic washers and a bit of plastic tubing to address the problem. Or just use some kind of plastic screws. Assuming one couldn't buy from some cheap source such as railbuttons.com as linked to by GalantVR41062.
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"Use screws instead of railbuttons" implies just screws. Using washers/bushings to make railbuttons is a thing and has been done.
I wouldn't trust a nylon screw to function as a rail button.
lr64
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Just how much force is on them? Wouldn't it depend on how powerful the rocket was? Of course, there are other plastics besides nylon, and I suspect brass or bronze, whether plating or solid, would be less likely to gall as well.
In any case, the specialized item is probably just as cheap, and all round rail buttons will be draggy.
In any case, the specialized item is probably just as cheap, and all round rail buttons will be draggy.
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With the old Estes "C" rails, I remember using nylon screws and the screw head rode inside the channel.
Of course these were for use on LPR
Of course these were for use on LPR
-Slick-Ice
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There are conformal rail guides also for 1010.
roytyson
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Just, Why? Of all the things to worry about, alternate buttons are one more thing to think about. They just work.
mperegrinefalcon
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Do not use metal parts for rail buttons. It will damage the rails at your club.
You can use a launch tower, conformal rail guides (not recommend, I see them break a lot), or the fly away rail guides.
Rocketjunkie
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lr64
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Wouldn't breakage depend on just how they are made, and of what? And couldn't they be screwed down like rail buttons instead of having a wide base that has to have about the right radius?
I have purchased them and have seen lost of flights with them. I have only seen them pop off the bird if not secured correctly. Zero breaks. Are you referring to the 3d printed ones?
mperegrinefalcon
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Yes, I am. I believe I have only seen those actually.
What are the other ones made of?
khabuda
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Giant Leap sells aluminum ones. https://giantleaprocketry.com/products/acme-rail-guide-3-00in
As said above, the originals are aluminum. I can print them so they do not easily break. Technique and material used are key to success.
mtnmanak
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For the conformal rail guides, I agree with Chuck - I have not actually seen them break (commercially purchased ones), but they can pop off the rocket.
If you use conformal guides, the absolutely most risky time is when you are loading the rocket on the rail - particularly the rear most conformal guide. Since they are straight and can not turn, if you rotate the rocket at all while sliding the rocket down until the second guide is in the rail, you have a high likelihood of ripping the lower guide off the rocket. It doesn't take a lot of rotation to put a large amount of torque on the guide (all you math whizzes out there can probably tell us how many degrees of rotation equals NN pound-feet of torque on the guide).
Bottom line, if you use conformal guides, make sure they are anchored very well and take care when loading the rocket on the rail.
For this reason alone, I do not recommend conformal guides for "large" rockets. It has nothing to do with the capacity of the guide, it has to do with your ability to keep the rocket straight while loading it on the rail. This will be different for everyone. If you feel a 10 pound rocket is "heavy" and you won't be able to keep it steady while loading, then that may be a "large" rocket for you. If you are a 6'7" linebacker and you bench press 400 pounds, then maybe a 50 pound rocket is like a little toy for you (this is not me, by the way - I am pretty much in the "conformal guides for rockets 15 pounds and under" camp
).
As for the OP's original question, +1 to everyone telling you not to use a screw all by itself. If you go to a launch and ruin the club's rail with a screw, I am pretty sure they will not be happy and, besides having to pay for a new rail, I am sure you will have bought yourself a whole new world of future RSO scrutiny... if they ever let you fly again.
If you use conformal guides, the absolutely most risky time is when you are loading the rocket on the rail - particularly the rear most conformal guide. Since they are straight and can not turn, if you rotate the rocket at all while sliding the rocket down until the second guide is in the rail, you have a high likelihood of ripping the lower guide off the rocket. It doesn't take a lot of rotation to put a large amount of torque on the guide (all you math whizzes out there can probably tell us how many degrees of rotation equals NN pound-feet of torque on the guide).
Bottom line, if you use conformal guides, make sure they are anchored very well and take care when loading the rocket on the rail.
For this reason alone, I do not recommend conformal guides for "large" rockets. It has nothing to do with the capacity of the guide, it has to do with your ability to keep the rocket straight while loading it on the rail. This will be different for everyone. If you feel a 10 pound rocket is "heavy" and you won't be able to keep it steady while loading, then that may be a "large" rocket for you. If you are a 6'7" linebacker and you bench press 400 pounds, then maybe a 50 pound rocket is like a little toy for you (this is not me, by the way - I am pretty much in the "conformal guides for rockets 15 pounds and under" camp
).As for the OP's original question, +1 to everyone telling you not to use a screw all by itself. If you go to a launch and ruin the club's rail with a screw, I am pretty sure they will not be happy and, besides having to pay for a new rail, I am sure you will have bought yourself a whole new world of future RSO scrutiny... if they ever let you fly again.
PML used to have them, believe they were cast from urethane resin
mtnmanak
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In theory, LOC still carries them - https://locprecision.com/products/linear-launch-rail-lugs-2-lugs-per-kg?_pos=60&_sid=8fbbb01f9&_ss=r
But, like most of the PML stuff, they are not in stock. PML is 80% gone and I am not sure if we will ever see those products again.
I would like to find a set of the 1 and 1.5 inch models to design a 3d printed version.
