# Unistrut Rail buttons

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#### NateLowrie

##### Well-Known Member
TRF Supporter
I am looking at doing a large run of Unistrut rail buttons. Right now there are only 2 suppliers that I know of: Aerocon (which is stupidly expensive at $12 a button) and Pro Line ($5 a button and I have not dealt with them before). If you are interested, I would love your feedback on the questions below.

Pricing:
1. Individual buttons with a stainless steel countersunk screw - $4.5 2. Pack of 10 buttons and screws -$40 (11% savings)
3. Dealer pack (50 buttons and screws) pricing - PM me.

Questions I would like feedback on:
1. Do you prefer Black or White buttons? Should both be available?
2. What screw size do you prefer? #10-24 or 1/4-20
• 1/4-20 is generally the size for these buttons.
• Most of your 1515 buttons use #10 screws. If these were made for a #10 screw one could swap 1515 and unistrut buttons more easily.
3. If these were made for #10 and you needed 1/4-20, would you drill the hole out to fit the 1/4-20 bolt?
4. Do you want well nuts available with the buttons?

#### djkingsley

##### Well-Known Member
Nate,

My I would take a 10 pack with 1/4-20 counter sunk screw.

#### NateLowrie

##### Well-Known Member
TRF Supporter
Forgot to mention a few things:
• Leadtime will be 3-4 weeks.
• Shipping to CONUS is free on the 10 packs and dealer packs.

Dennis, do you care about the color?

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#### djkingsley

##### Well-Known Member
White, and if you have them for the September MDRA launch you can bring them then. The BourbonRoc won't see any serious build time until then, currently purchasing parts. Send me a PM to arrange payment.

#### cwbullet

##### Obsessed with Rocketry
Staff member
TRF Supporter
Global Mod
I would 2 packs of 10 of what every color and screw you decide to use. I do like the idea of using a universal screw size between unistrut and 1515.

#### Rocketjunkie

Definitely 1/4-20. All the 1515 buttons I've seen are also 1/4-20 (and when I made them for railbuttons.com).

TRF Supporter

#### jsdemar

That is a very good price. I used to make them for Quickburst 10 years ago and he sold them $10.50/pair. I think I made 250 or so. Attached are the dimensions I came up with at the time. You are welcome to compare this to what you plan on making. They were a very good fit and worked well. It is based on these dimensions from Unistrut: #### NateLowrie ##### Well-Known Member TRF Supporter That is a very good price. I used to make them for Quickburst 10 years ago and he sold them$10.50/pair. I think I made 250 or so.

Attached are the dimensions I came up with at the time. You are welcome to compare this to what you plan on making. They were a very good fit and worked well.
View attachment 324574

It is based on these dimensions from Unistrut:
View attachment 324575
You drawing and mine are within .01 most places. I did make the base flange .42 instead of .21 to get the rocket body a little further off the rail, which is pretty much what most of the buttons are running nowadays. Thanks for sharing.

#### jsdemar

##### Well-Known Member
You drawing and mine are within .01 most places. I did make the base flange .42 instead of .21 to get the rocket body a little further off the rail, which is pretty much what most of the buttons are running nowadays. Thanks for sharing.
With 0.21", you can add a delrin disk or stack of fender washers to get more standoff from the rocket. I've seen people do this only when there's some sort of scale feature. For most rockets, 0.21" is more than enough. And it saves on cost of material.

#### llickteig1

##### KLOUDBusters Chief Logistician
1/4"X20 is a must. I can't imagine a rocket needing Unistrut buttons not needing the beefiest bolt available.

Color doesn't matter one whit. If one is cheaper for you, use that. Our biggest Unistrut project was painted white but had black buttons. You can't really even see the button when the rocket is on the rail anyway. Unistrut rockets are not shelf queens.

Thanks for doing this. Paying \$12 for a single button seems like robbery. I'm not even planning a Unistrut project, but I'll buy some.

Thanks, --Lance.

#### Brent

##### Well-Known Member
Personally I like black. My Unistrut buttons and 1515 are both 1/4-20. I would be interested in a couple sets.

#### NateLowrie

##### Well-Known Member
TRF Supporter
John, you brought up some good points on the spacing. I ended up adopting your spacing of 0.21". I've attached the drawing for anyone that wants to view it.

View attachment Unistrut Button.PDF

#### jsdemar

##### Well-Known Member
John, you brought up some good points on the spacing. I ended up adopting your spacing of 0.21". I've attached the drawing for anyone that wants to view it.
Hi Nate, you might consider changing the 1.3" OD to 1.25". You can get 1.25" delrin stock and not have to turn down something larger in diameter.

Also, the outside lip depth is most important because it is the part that will shear and pull the button out of the rail slot. I went with 0.23" min on the outside because it allows for the screwhead countersunk without it taking some "meat" out of the center barrel where it meets the outer lip (if that makes sense). You need to show the hidden line for the countersink in your drawing to see what I mean.

#### NateLowrie

##### Well-Known Member
TRF Supporter
Hi Nate, you might consider changing the 1.3" OD to 1.25". You can get 1.25" delrin stock and not have to turn down something larger in diameter.

Also, the outside lip depth is most important because it is the part that will shear and pull the button out of the rail slot. I went with 0.23" min on the outside because it allows for the screwhead countersunk without it taking some "meat" out of the center barrel where it meets the outer lip (if that makes sense). You need to show the hidden line for the countersink in your drawing to see what I mean.
John, I have a ton of 35mm stock that I was planning on using, so the 1.26in diameter does not bother me. Actually, I prefer turning it down because I can machine out any gouges, scratches, or material irregularities.

Good point on the lip depth. I did account for that but did not spec it in the drawing. If you look at the screen grab below, the countersink does not go into the center barrel at all. I got .061in between it and the center barrel. Given that it's going to be CNC machined, I am not worried about overshooting the depth. The countersink is also a little larger than standard (.55 instead of .5310) to sit the screw just slightly below the surface.

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##### Well-Known Member
TRF Supporter
Yup, I'd be interested in some 1/4"-20 ones at that price. I was thinking black, but might want both...

#### NateLowrie

##### Well-Known Member
TRF Supporter
Yup, I'd be interested in some 1/4"-20 ones at that price. I was thinking black, but might want both...
After talking with some of the vendors, we will be making both black and white. Everyone will have a choice and the 10 packs and cases can be whatever combination of colors you want.

Also, leadtime has been updated to 2 weeks. I should start shipping these around 8/11.

I have a list of everyone that wants some. I will be contacting you when they are done to get what colors you want and arrange shipping/payment. As with any product I sell, these buttons come with a 30 day money back guarantee. If you don't like them, we'll take them back and refund you no questions asked.

Staff member
TRF Supporter
Global Mod
What are cases?

#### NateLowrie

##### Well-Known Member
TRF Supporter
What are cases?
50 unit cases. Designed for vendors that want to resell.

#### jsdemar

##### Well-Known Member
You may be over-estimating the market size. I can't imagine there are that many big/fat rockets flying off of Unistrut. The trend out here in the Southwest is to use 1515 backed with antenna tower reinforcement. I've launch 8" dia, 140# rockets with O motors that way. Probably more people back East using Unistrut. But, 1515 is the bulk of the big rockets, I think.

#### NateLowrie

##### Well-Known Member
TRF Supporter
You may be over-estimating the market size. I can't imagine there are that many big/fat rockets flying off of Unistrut. The trend out here in the Southwest is to use 1515 backed with antenna tower reinforcement. I've launch 8" dia, 140# rockets with O motors that way. Probably more people back East using Unistrut. But, 1515 is the bulk of the big rockets, I think.
I would agree with you on the sizing. On the east coast, I am finding most of the big towers are Unistrut. I am not expecting to sell thousands, but a smallish run of a few hundred is sized about right. The main goal for me is to bring down the price and increase availability of high quality buttons. Based on the orders I have I think I got close.

#### tbonerocketeer

TRF Supporter
You may be over-estimating the market size. I can't imagine there are that many big/fat rockets flying off of Unistrut. The trend out here in the Southwest is to use 1515 backed with antenna tower reinforcement. I've launch 8" dia, 140# rockets with O motors that way. Probably more people back East using Unistrut. But, 1515 is the bulk of the big rockets, I think.
I flew my 200lb P project on 2 1515 rail buttons.

##### Well-Known Member
TRF Supporter
The MDRA away cell towers are Unistrut.

#### AlphaHybrids

##### Well-Known Member
I've just always used doorknobs for Uni Strut buttons. HD/Lowes always has some nice ones in stock.

Edward

#### Tonimus

##### Well-Known Member
I only have one rocket with Unistrut buttons at the moment. I expect to add a few more. I think I'll continue to use Unistrut for anything that isn't going for max speed/altitude. I don't remember who I got my rail buttons from, but I had to open the slot up on them to fit the Unistrut I have. The Orange Box store uses "Superstrut" and the rolled lip is a little bit bigger than actual Unistrut.

#### pondman

##### Serenity now......
I'll take a couple of sets.

#### NateLowrie

##### Well-Known Member
TRF Supporter
I'll take a couple of sets.

The buttons are just about done. I will add pictures shortly. I expect to be shipping this week. For everyone that wanted some, I will PM you about details for payment via PayPal.

#### NateLowrie

##### Well-Known Member
TRF Supporter

Note the screws will be stainless steel. Just popped in a 1/4-20 I had close at hand for that last shot.

#### jsdemar

##### Well-Known Member
Note that stainless steel screws are low strength compared to cap screws. Flat head cap screws, F835 grade, are about 2x as strong as stainless.
But the weakest link is usually the mounting point into the rocket.

#### NateLowrie

##### Well-Known Member
TRF Supporter
Note that stainless steel screws are low strength compared to cap screws. Flat head cap screws, F835 grade, are about 2x as strong as stainless.
But the weakest link is usually the mounting point into the rocket.
I chose 304 stainless for the corrosion resistance. A 1/4-20 flat head cap screw in 304 SS has a shear strength of around 1,900lbs, which should be more than adequate for the job.

If you want zinc plated F835 I can do that too. I just didn't think it was necessary.