Impass tring to mount turnout servos to the underside of a layout

[videobruce]

For those who have dealt with SG90 type servos to control turnouts:

Long story short, I have around 60 Peco electrofrog turnouts that need under table servos to be mounted and it's come apparent the job is far harder to do than I ever anticipated when I design my layout 11 years ago. Unknown (or more likely never thought about it) some of the locations are so close to one another and/or partially blocked by support framework, making things worse. The mounts are Motrak. These were all purchased around 10 years ago together. So far all the servos are working (believe it or not, more than I can say about the servo controllers I purchased from Tam Valley the same time, but that is another story)

My other problem is positioning the mount exactly where it need to be either with or w/o the servo attached. I'm running the piano/music wire down from the top as opposed to pushing ti up from the servo horn which I see as adding gravity working against me.

I pretty much ruled out screws that have to have pilot holes drilled and hot glue that will drip down (probably on my hands) and make a mess. What I came across that actually may work is something called "Alien Tape" which is a 3/4" wide 2mm thick very sticky double sided clear tape suggested by someone elsewhere.

I'm not sure if I should attach the servo already mounted, or just attach the mount w/o the servo so I can get a better idea of exactly where to secure this based on the 'travel' of the wire thru the fulcrum from side to side. If I have the servo there in place, I can't really do that since the horn prevents movement. (I don't want to try to move the horn by my hand, most seem say not to do so. I'd rather stay on the side of caution.)

Any input here from anyone that has gone the servo route?  I hope all of that made some sense. 

[videobruce]

Before someone asks, I didn't go the Tortoise route due to size and cost. They are too large for N scale and the cost is over 3x the cost. Servo & mount under $5, Tortoise $16 in packs of 12 (lowest I initially found).

[newt749]

I don't use a mount like yours, I 3d printed mine from Sumner's design so I won't comment on that. However, I do use a very cheap servo tester, which are available from multiple sources, to test my servos in situ. Just attach the cable from the servo to the tester and a power supply. I use a set of 4 AA batteries in a battery holder. The tester will allow you to activate the servo in order to see if the throw is sufficient or not. Once you know your okay you can hook it up to your controller.

Rob
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[videobruce]

I do have the same thing, it's ok as a tester, but I can test using the Berrett Hill 'Servo Base' controllers when I pre-programed them. I made up a jig with the servo mounted to a 3/8" of plywood glued to 1/2" of foamboard (minus the cork roadbed) with the turnout attached.

[videobruce]

No other input here, no one using servos?

[C855B]

Yes, but I'm using a different approach and didn't want to rain on your parade. Try here, from five years ago: https://www.therailwire.net/forum/index.php?topic=40197

Two changes since that vid. First is a slab of 0.005" or 0.010" styrene underneath the ties to keep ballast from falling into the cutout well. Second is some versions of the servo weren't happy with the solid link, so I use a formed hairpin spring link to relieve the pressure.

I have about 100 of these deployed now, with another 150 to go. Some have been in service for over five years, so it's a sound concept.

[BCR751]

OK, I'll chime in for what it's worth.  I use the Tam Valley mounting system for all of my turnouts.  It can come as either a kit or fully assembled.  It consists of a 3D printed mount, the SG90 servo, the throw wire and a piece of double-sided sticky tape.   With the servo mounted in the mount and the sticky tape attached to the bottom, I carefully run the throw wire up thru the sub road bed and thru the throw bar on the turnout and GENTLY press the sticky tape on to the bottom of the roadbed.  I then check the alignment of the throw bar to make sure it's centered between the rails in the turnout.  If it isn't, I carefully move the assembly until it is.  I then carefully drill two pilot holes diagonally apart and insert the screws and snug them down.  Then, when I'm satisfied the alignment is good, I tighten those screws and drill and attach the remaining two screws.  I really like this system.  I admit it is difficult if the turnout is in a weird place, like right above  a riser or joist but i usually find a way to work around those.  My biggest problem is trying to be a contortionist while attempting access to hard to reach spots.  I have about 30 more turnouts to install so the end is in sight.

Doug

[videobruce]

C855B;
That's in HO scale?


BCR751;
That sounds as complicated or even more then what I'm looking to do. 

[C855B]

C855B;
That's in HO scale? ...

N.

[Jim Costello]

Too add my 10 cents worth I have installed over 200 servos on the underside of my track and yes there has been some difficult areas.  To make things easier for me to install I made
a small jig..a piece of the steel wire mounted vertically to the end grain of a piece of 2 x 1 dressed timber that sits vertically on my track, with the wire passing through the tie bar.
I then install the servo onto the bracket and pass this wire through the base so that it passes below the depth of the servo.I make sure the wire is then vertical against the servo, both ways  and then press the bracket
into place before using the screws. I also use smaller screws, both in gauge and length into 1/2" ply base.  Recheck to ensure the wire is still vertical.
 I use the servo centering tool to centre the horn location and after ensuring the wire passes through the tie bar I engage the horn to the servo. If you can hold the servo horn before mounting to the servo itself place a
piece of masking tape around the wire protruding up through the tie bar.....it will not fall through onto the floor as you try to mount it onto the servo. Once installed setting up I have found the Quad pic the easiest to use.
All my turnouts are hand made so I use relays to power the frogs.
In areas where it has been difficult to mount the servo control wire through the base and through the tie bar I purchased some 36" lengths of wire, the same diameter as supplied wth the mounting brackets, and putting a piece of tape on the end of the
wire and pushed it through the tie bar and mounting bracket. I then bend the wire as required fitting on to the servo horn and it is then easy to pull through and mount to the servo. I cut the wire to make it easy for final adjustment (put a piece of tape over this end
before trying to adjust/relocate the servo horn

The servo mounting brackets (Motrak) are no longer available. In using them we have had some issues, the bracket is a soft urethane casting and over time the servo will tend to drop down on one end.The servo is held by only one screw. I have had to reinstall some
by gluing the servo into the bracket( I had no alternative bracket at the time) and remounting. My tie bar is only 0.032" pcb so it does not take much for the wire to fall out. To overcome this I solder a smaller piece of pcb under the point were the throw wire passes through
giving it twice the thickness.  I now use the Tam Valley  3D printed mounting brackets fro Tam Valley.

Hope this may help

Jim    NHRHTA #L082
Modelling the NH down under

[videobruce]

C855B;
Wow, that surely looked like it was HO scale.
So I understand the arrangement, that servo is attached to the ties of the turnout and you 'dig out' a opening in the foamboard deep enough so the servo will fit below grade but not deep enough that it's visible underneath. Is that the idea?
I wish I knew that 11 years ago. 
Thou it wouldn't really work here since I have 1/2" foamboard over a 3/8" sheet of plywood, not solid foam like yours since I wanted strength that I can lean on the layout if needed (which it is in a few locations  )

[videobruce]

Jim;
200 servos?? 

I kinda got lost in the description of your mounting system Do you have any pics to share?

Those Motrak mounts are available. I contacted the owner and he still has the plans to 'print' more. I was short around 10 and had to order more. They aren't on his web site but he can make more. It's a slightly different design with a 2nd post for the other screw, but that 2nd post gets in the way of the 3 conductor cable of the servo. I had to cut it off so the servo would fit without crushing the wire.
I too have sen potential issues with this mount which is probably why he discontinued advertising them even with his 2 post version (which should solve any 'rocking' issues).

What adhesive did you use to secure the servo to the mount?  I find that type of 'plastic like' material very 'slippery' and question an adhesive that will actually hold.

[John]

No other input here, no one using servos?

I have a box of 20 servos and an arduino that I am going to use with a DCC interface  --- just haven't gotten around to it yet .. but watching this very carefully

[Sumner]

Easy mounting system for my servo mounts but one could make something similar for other servo mounts.  More about it here ...

http://1fatgmc.com/RailRoad/Servo%20Control/page-12.html



I have a similar system for mounting my 'Gravity Switcher' switch machines here...

http://1fatgmc.com/RailRoad/Trackwork/page-26-b.html

Sumner

[videobruce]

But that assumes one has access or owns a 3d printer (which are few and far between) and isn't using servos.
And it also assumes that one isn't setup for CTC (Centralized Traffic Control) operation as opposed to 'local control' (Interlocking Towers).