# Easy insulating rail clamps? Will they work?



## dawgnabbit (Jan 2, 2008)

Hi, All

Has anyone tried making their own insulating rail clamps with flat head screws and a plastic base? Will this idea work?

I tried out the concept with a scrap of black ABS plastic and four #4 x 1/2 flat head sheet metal screws: 












Very cheap, very fast to make, but will it work? Opinions, please.

Thanks,

Dawg


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## Greg Elmassian (Jan 3, 2008)

I am missing the insulating part... are you intending to gap the rail? If so you will see that you don't have enough support of the rail to keep the ends aligned.. 

Regards, Greg


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## wchasr (Jan 2, 2008)

Turn the ABS 90 degree's add in 4 more screws and cut the rail in between the middle pair. 

Chas


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## John J (Dec 29, 2007)

I think you are on the right track. I can see that if you placed that on a joint and left a gap that would work. My question would be is there enough threads in the ABS to for the screw hold. 

If the bite of the screw were in question I would double the width of the ABS and put in 4 screws, two on each side of the gap 

I Really think you go soemthing cost effective there . 
Plus the pleasure of making your own stuff. 

JJ


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## Axel Tillmann (Jan 10, 2008)

Judging on how commercial insulation clamps are made you need to consider the following: 

First:
Plastic doesn't have enough strength (and weakens over time) for "metal/wood" style screws. The threads will not hold well in the long run. That's why a nut and bolt method is preferred, however creating the challenge that you need a hex indent for the nut to stay in and not move so that the bolt can be screwed down tightly. 

Second: 
You need to consider a plastic strip between the two rails preventing that on expansion the rails will not touch

Third:
If you don't have a supporting groove on the other side but just a screw as well then holding the rails with just one screw on each side is not enough support. You will have to double the width of the piece of ABS to use 4 screws per rail. 
Example of commercial clamp.


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## Greg Elmassian (Jan 3, 2008)

I agree, without more screws to keep the rails aligned, or a "groove" to align the foot of the rail, the design shown will not work. 

As JJ pointed out, and I agree, with heat and expansion and contraction, fine threads in abs will not hold, you need a metal nut on the other side. 

Look at all the successful insulating rail clamps, if they could have done it cheaper they probably would have, but I think your metal screw needs threads in metal to hold. 

Regards, Greg


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## dawgnabbit (Jan 2, 2008)

Gentlemen, thank you for the good advice. I agree that the manufacturers have vastly superior designs that have been well tested. At upwards of a buck and a half a copy, though, I need to find something cheaper. 

The photo was just a first experiment. I'm still experimenting with the concept and I'll embody your suggestions as much as possible. When (and if) I come up with something that seems like it will work, I'll post a photo and impose upon you for comments and advice once again. 

Again, thank you all. 

Steve Seitel


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## wchasr (Jan 2, 2008)

Steve, 
IF you think you need metal threads there are a number of options to add threads from as simple as drilling thru the ABS and putting a nut on the bottom to as complicated as some engineered fasteners like the PEM inserts (http://www.pemnet.com/fastening_products/pem-self-clinching-fastener_new.html) or some other "solution. Based on the expansion and contraction you need to make sure the rails cannot "grow" into each other there-by making inadvertent contact by adding some sort of plastic spacer for insurance. I think you can get there but you need to weigh the time vs cost factor here. How mush is your time worth versus a pre-made solution? Then add in the enjoyment factor. Do you enjoy tinkering like this? 

Chas


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## Totalwrecker (Feb 26, 2009)

One thing I notice as I'm tightening the tiny SS screws in the Aristo joiners is that I have to really tighten them to bring the rail heads into alignment. 
I see nothing in your design to ensure smooth running. 
How about instead of the screws touching the rail you add a 1/8th" plastic on both sides that when screwed down presses into the rail web. 
You will still need an anti-expansion insulator between the rail ends. 

I would heat set the nuts into the bottom side of the base plate; screw thru hole, nut screwed on and as pulled from opposit side as a large soldering iron heats the nut allowing it to melt it's way in. The screw in the nut will keep the threads clean. 

John


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## dawgnabbit (Jan 2, 2008)

Okay, here's a second go at the homemade rail joiners. I've adopted quite a few of your suggestions. First, rail-to-rail alignment is ensured by an undercut ledge, milled with a 14 degree dovetail bit in my router table. Second, a 1/16" plastic pin guarantees the rail heads cannot touch. I'll probably make it a 3/64" pin, because that gap looks a little large to me. Third, the plastic is thicker and the screws are bigger: #6 x 1/2". I expect I'll use stainless screws instead of bronze-finish steel, though. Finally, the block is a little longer; it's as long as I can make it and still slip in between two ties.






















My big remaining worry is Axel's (and others') comment that the plastic won't hold screws for long. If I have to go to helicoils and machine screws, or try to melt a nut into the bottom (clever suggestion, that, John), then it probably won't be worth my time to make these. Otherwise, yes, I do enjoy "tinkering" in the shop with things like this. With the machines all set up for repetitive cuts, I think I can turn out 10-15 of these assemblies in an hour.

Your suggestions last time were most helpful to me. Please let me know what you think of this one.

Thank you all again,

Steve Seitel


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## Axel Tillmann (Jan 10, 2008)

You are getting close to the commercial version as shown in my picture.







Of course when you have all the time at your fingertips then why not - go for it. I on the other hand only like to build what isn't available on the market and I have a long list on that, hence I don't tinker with stuff that is commercially in the right quality available.

Point in case I would never solder a DCC system, or Build an RhB Gem 4/4 (Diesel/Electric engine) both commercially in the right quality available. But if time doesn't count and you have joy at it. Power to you. You are a lucky man, there doesn't seem to be a honey do list either







.


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## Greg Elmassian (Jan 3, 2008)

I'd say that's as far as you can go without machine screws and nuts, and a single "fixing point" per rail. 

If the rails are pre-bent, I'd say that would last a while, but you will want SS screws, what you have will rust. 

If you were using SS rail, I think that you might not be able to have enough clamping force to ensure rail alignment. 

For brass, I'll bet what you have is workable. (just get rustproof screws, even galvanized ones would be better) 

Regards, Greg


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## Dick Friedman (Aug 19, 2008)

Your design looks very similar to the clamps that San-Val used to sell. Theirs used four machine screws as you did, threaded into a small metal plate. Yours could work, especially if the ABS is as thick as the ties (for some bite). Maybe machine screws with nuts would not strip out.

Perhaps a plastic "c" channel whose back side is the width of the bottom of the rail could just be slid onto the rail.


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## SandyR (Jan 6, 2008)

What about the plastic 'c' channel as above, with a strip of plastic glued in crosswise, to keep the rails separated? No need for screws then, I'd think; the rails would 'float' in the joiner...Just a thought...everything works in my thoughts, but a good half don't work out in the real world! 
SandyR


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## Greg Elmassian (Jan 3, 2008)

You have to have screws to hold the rail in alignment. The San Val ones with the screws on both sides took a bit of finesse to get the rails aligned... the ones with screws on one side and a v groove in the other guarantee alignment. 

Regards, Greg


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