# Bellcranks with Tortoise switch machines



## Cab1 (Jul 26, 2009)

Has anyone out there tried to use RC airplane 90 Degree Bell cranks with Tortoise switch machines? I plan on using the new "Smail" integrated logic units that Circuitron came out with awhile back on my layout; but I think the question applies to the standard Tortoise and Tortoise clones as well. After going over the installation instructions, a couple of things kind of jump out at me. One being almost universal agreement the wire that comes with it is too flimsy and should be replaced with .032 music wire and the other having a big open hole under the track right where the track ballast will be going. Putting that aside there doesn't appear to be a whole lot of room for adjustment. I think these problems could be addressed by using Kwik-Links and a couple of Bell Cranks. Once you get the geometry right, all the installations would be the same. I saw a double crossover some guy on the coast rigged up, but not on a plain old turn out. I'm sure somebody out there has done it.


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## gregc (Apr 25, 2015)

you might consider









and


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## CTValleyRR (Jul 26, 2014)

Cab1 said:


> Has anyone out there tried to use RC airplane 90 Degree Bell cranks with Tortoise switch machines? I plan on using the new "Smail" integrated logic units that Circuitron came out with awhile back on my layout; but I think the question applies to the standard Tortoise and Tortoise clones as well. After going over the installation instructions, a couple of things kind of jump out at me. One being almost universal agreement the wire that comes with it is too flimsy and should be replaced with .032 music wire and the other having a big open hole under the track right where the track ballast will be going. Putting that aside there doesn't appear to be a whole lot of room for adjustment. I think these problems could be addressed by using Kwik-Links and a couple of Bell Cranks. Once you get the geometry right, all the installations would be the same. I saw a double crossover some guy on the coast rigged up, but not on a plain old turn out. I'm sure somebody out there has done it.


I've never actually heard anyone having issue with a big open hole under the track, especially not "right where the ballast is going to be". First of all, that hole is only going to be about 3/8", most of which will be covered by the head block ties and throw rod. You don't want any ballast in there anyway; it's too easy for it to get jammed. I circled the area which will be over the hole. If a bit of the hole is showing out from under the head block ties, use a small piece of styrene or basswood to cover it.









Your activation wire goes right up through the roadbed and engages the throwbar (I use that center hole). Whatever method you use will need to provide about 1/8" of lateral movement (in HO) perpendicular to the tracks in that area.

I don't know about adjustments; I use Tam Valley Depot servos and they can self-calibrate to throw the right distance in either direction, as long as the points and the activating wire are reasonably centered when installed, and the wire doesn't hit the sides of your hole.

Installation is easy; as long as there are no obstructions under that area of track, take a 6" length of brass tube with an ID just larger than your activating wire. Drill out the center hole in the throwbar so the rod just fits down through, and feed the activating wire up through the rod. Align the servo arm's throw perpendicular to the track and secure in place. Pull out the brass rod, leaving the wire in the hole. Trim it so it just barely protrudes in the center of the throw.

I only use a bell crank if there is an obstruction (like a joist) that prevents me from placing the servo directly below the turnout.


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## flyboy2610 (Jan 20, 2010)

About 1/3 of the way down the page:
http://melvineperry.blogspot.com/2012/06/june-25-2012-my-double-crossover.html


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## gunrunnerjohn (Nov 10, 2010)

I'm sure you can use a bellcrank with them, I've seen home made ones at our club layout. As far as why you wouldn't be able to put the slot under the switch machine, sometimes there are obstructions under the switch.


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## CTValleyRR (Jul 26, 2014)

gunrunnerjohn said:


> I'm sure you can use a bellcrank with them, I've seen home made ones at our club layout. As far as why you wouldn't be able to put the slot under the switch machine, sometimes there are obstructions under the switch.


I think the OP's objection was having to put a big hole in the layout surface to allow the activating wire to move, not that he couldn't put one there. Obstructions usually do require some way to offset the turnout machine.


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## gunrunnerjohn (Nov 10, 2010)

Well, the hole is another issue, but those are usually not that obvious if done carefully.


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