Point Operating Mechanism- Cheap and works well!
Entry posted by devondynosoar118
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Having come across lots of ways to do the electrofrog points dance, I was inspired to make these for our set up. The kids said they wanted it simple to operate, and I wanted play value built in to encourage them to really work as a team at exhibitions. This method is cheap at less than £1.50 a point and fairly simple to construct.
You need-
Brass strip, 25mm+ wide
Brass rod- fairly thick, 3mm min
Brass tube which fits over the rod as a sleeve.
Soldering kit- if you haven't soldered structurally before this is a good practice project as the parts are cheap.
Cheap sliding switches, 3 contact type, 2 power one common earth, small or medium. Medium are better for OO.
If using a smaller switch- i.e. one that wont take being drilled for the rod, get some square section brass to fit over the switch.
Some "chocolate block" screw terminal connectors.
small self tapping pan head screws
Araldite rapid or other 2 part fast epoxy
This method assumes a feed has already been run to the frog. Wiring colours for me are brown/blue are bus wires (DC in this case, but capable of DCC operation as well.) red for the frog wires.
Here is the general assembly.
Start by forming the omega loop from a length of brass tube. It allows flex in the linkage and gives a bit of snap to the micro switch operation. I put this nearest the baseboard edge usually.
If you need to join more lengths together, use the sleeve tube and join with solder. I work out the lengths of the operating rod, then prepare the support brackets. if you have a short run of less than 1ft, then the hole in the base board edge, 1 bracket and the switch will be enough to keep the rod supported.
To make the bracket, work out the height you need to mount the microswitch off the baseboard, usually this is not much, less than 1/4" seems to be fine. This measurement should be from the base board to the centre line of the switch. Then mark the centre of your brass strip, mark and drill a hole the same dia as your tubing somewhere near the top. Measure down the same amount as the bracket height, scribe your fold line here, then measure another 1/2 inch or so down the strip, this is your cut line. Cut it and bend on the scored line to make your bracket. Sounds hard but isn't you are only making an l shape with a hole in!
I then make the microswitch bracket, method the same but slide switches need a square hole, so some filing is required to make them fit and they are secured with tiny self tappers at each end. Mark and drill all holes before cutting and bending.
Switch bracket finished.
Now link it all up, take the omega loop, slide some tube on to the section where you want to put your support bracket. If you are using a big switch, drill a hole in it on the face that you would push i.e. not in the side! If using a smaller switch, drill a piece of square bar to fit the sleeve tubing and cut it off long enough to cover the switch.
Line it up with the usual slot cut under the tie bar, and mark where the hole in the baseboard edge will go, drill it for the sleeve size and cut some sleeve to fit through, glue it in. Thread the rod thru, line up with the tie bar, then screw down the support bracket. put the sleeve in place and solder to the bracket.
You are now ready to fit the slide switch to the rod too. Find the end, put the point in the straight ahead position, and put the rod through the hole in the switch or the square section slid on top of the switch if you are using small ones. Mark the mounting screw positions, then pilot drill holes and put the bracket in place. If you need the square brass on the switch DONT fit the switch yet as you will melt it when you solder, fit the sleeve into the square section and solder in place, then fit the switch.
Here is where you need the epoxy glue. If you used a big switch, put the rod in the hole and epoxy in place. If you used square brass like me, fit it over the switch and glue. leave to set before testing the movement.
Now the tiebar. If you have Peco style points with a hole in the middle, thread some brass rod down to the new mechanism from above, cut this length plus a few mm each end for tweaking. Bend the end that goes under the board thru 90deg, push the rod so that straight ahead on the point is up on the switch, clamp the rod to the point mechanism and solder it. you can move it around to get the throw right by soldering it in different places up/down the actuating rod.
Then put a single choc block connector as a handle on the bit of rod sicking out the side of the board and you are done. These can be colour coded by wrapping in insulation tape.
Make the electrical connections. Check your polarities, oif you get a short, swap the bus/power feeds over, not the frog wire.
I made the mechanisms and the young people soldered them together, if you simply copy the picture you should get a working, DCC friendly solution for less than £1.50. Apologies about long winded explain! Points were cut and cross bonded as per Brian Lamperts DCC pages first. All works fine on DC, even with a dodgy Bachmann pancake motored american diesel.
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