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Rail Guides - Button, Acme, PML?

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RCBrust

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I'm trying to decide what type of rail guides to use and am looking for opinions from those who have used them. I've always liked the Acme conformal lugs for rods and had pretty much decided on their conformal rail lugs until I saw a post on Rocketry Planet where it was stated that some clubs don't like them because they dig up their rails. Everything else that I've read about them, however, has been positive.

So, what are you guys using, and liking? Standard delryn buttons? Acme? Or perhaps the PML plastic guides?

Thanks,
Randy
 

Handeman

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I've actually used all three. I didn't have any issues with any of them. The key for any of them is alignment.

The Acme and PML can be easier to align because you can put them against a single piece of angle stock to align them directly. I just used epoxy to attach mine and they have held up great.

The buttons are mounted on a straight line, but also the screws holding them on have to be perpendicular to the tube, or at least both at the same angle relative to the center line.
 

blackjack2564

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Since the get go, I have used rail buttons, always got them from www.railbuttons.com cheap, easy to mount and replace.

I have seen to many conformal type bind or get torn off, probably due to dirty rails. Not to many clubs clean their rails on a regular basis. Buttons have never seemed to be a problem fitting them.
 

AndyC

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I bought some of the PML rail guides (plastic not metal like the ACME ones) to use in a place where it was not easy to put in a screw. I found them a bit harder to line up than launch lugs, which are pretty easy to align by just sighting down the tube - for the PML guides you really need to use a straight edge.

Since then, I've gone out of my way to find ways to mount rail buttons. They are far easier to align - just stick them on a line drawn down the tube, there is no angle to fuss with. I've also found that they do not need to be perfectly perpendicular to the tube. By accident I broke into the edge of a ring, so the screw was not in perfectly. There's enough play to get away with a little bit of tilt. You do have to be careful about that though - don't want them to bind on the rail.
 

troj

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With metal buttons, it's imperative you use a rail to line them up, or they'll gall the rail badly. Not everyone has a rail, and it can take just a minor misalignment, which is why some clubs frown on their use.

Me? I don't like them, because I've seen them pop off.

I caught a nice photo of a fellow club-member's rocket about 1 foot away from the end of the rail, because the rail buttons guides had popped off.

For such a critical component, I much prefer a more solid connection.

-Kevin
 

RCBrust

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Ok, I think you guys talked me into the buttons. Is railbuttons.com the place to go or are there any other good sources for them?

Thanks,
Randy
 

troj

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Ok, I think you guys talked me into the buttons. Is railbuttons.com the place to go or are there any other good sources for them?
railbuttons.com is a good source.

Many dealers (Wildman, Giant Leap, etc) also carry similar style rail buttons.

-Kevin
 

falingtrea

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What do folks use on the inside of the tube to fasten buttons down? I am kind of partial to blind/t-nuts because it has more surface area for glue. I usually remove the prongs or make sure there is enough glue to cover them.
 

ttabbal

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Inside? Nothing. I just drill a hole, put in some CA, let it dry, then thread the screw in with a little epoxy in the hole and on the outside. I haven't lost one yet, K motors with about 5 lbs of rocket is about as high as I've gone. For future projects that are much bigger, I'll likely put something in there to help it hold. I figure if the glue-on conformal guides stay on, and they always have for me, there isn't enough stress on them to really worry about it for the projects I've done this far. My L3 project will be a different story, but that's a whole new ball of wax. :)
 

MarkM

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To mount my railbuttons, I use expansion nuts sometimes called well nuts. They are a brass insert inside a rubber sleeve. Put the expansion nut in, then thread the screw for the railbutton into that. You'll need a slightly longer screw than the ones which come with the railbuttons.

These have worked great for me. Easy to install and makes the railbutton easy to remove/replace if necessary. I've used these on my 40lb 6" L3 project as well as 12" 125lb rocket flying on an N not to mention all of my other 3" & 4" rockets of varying lenths and weights.
 
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ttabbal

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To mount my railbuttons, I use expansion nuts sometimes called well nuts. They are a brass insert inside a rubber sleeve. Put the expansion nut in, then thread the screw for the railbutton into that. You'll need a slightly longer screw than the ones which come with the railbuttons.

I've heard of those, and they look interesting. I haven't been able to find them in the local Home Depot or Lowes though. It would be really nice if someone selling buttons offered them so I could buy everything from one place.
 

blackjack2564

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Ken at Performance Hobbies sells them with the buttons, both sizes. They are also on the auction at The Planet upon occasion. Local hardware stores like Ace and Tru Value are known to carry, and as always....MacCarr!
 

Lucas

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We use rail buttons on all of our rockets. They have worked 100% of the time on rockets ranging in size from G-N. They are definitely the way to go!
 

snaquin

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I use 1010 buttons. First ones I tried I bought from BlackSky and really liked them. Those were acetal buttons (Delrin). When I used up the last of the BlackSky buttons I purchased some from LOC/Precision with a kit order when I realized Barry had them on the site.

I used the standard 1010 buttons on a Big Nuke3E that was about 14lbs with a K motor at Southern Thunder but I had attached the buttons with epoxy into holes drilled into centering rings.

I now use these on all my builds even on rockets as small as a LOC Aura because traffic at the rails is usually much lighter than the 1/4" pads, at least at our launch site.

.
 
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falingtrea

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I've heard of those, and they look interesting. I haven't been able to find them in the local Home Depot or Lowes though. It would be really nice if someone selling buttons offered them so I could buy everything from one place.
I think they are in the custom fastener section of Home Depot or Lowes. Where they have the bins of all kind of unusual nuts, bolts, fender washers, wood furniture fasteners, etc.
 

Richard

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Since the get go, I have used rail buttons, always got them from www.railbuttons.com cheap, easy to mount and replace.

I have seen to many conformal type bind or get torn off, probably due to dirty rails. Not to many clubs clean their rails on a regular basis. Buttons have never seemed to be a problem fitting them.
For some time I have wanted to start using rail buttons on my rockets and I just ordered a score from this site. The shipping was even reasonable.

Thanks for the tip.
 
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