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Help with installing SPDT switches?

3979 Views 13 Replies 7 Participants Last post by  Jerry McColgan
I have a quantity of switches that I would like to use on my layout but they require a rectangular slot to install (snap) into.

I don't know where I could find such a board with slots that I could put anywhere from 6 up to 10 or 12 of these switches.

I could simply use a jig saw to cut a large opening but the switches are not well suited to putting multiple units into a large single opening.

My thought is to try auto supply stores as I think they are intended for the automotive market but I thought I would ask here first.

Any ideas?


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SPDT switches
For a start, the photos show they are DPST, not SPDT. From the diagram, they are double-pole on/off switches. The spade connectors and the 12V suggest they are automotive, as you say.
I could simply use a jig saw to cut a large opening
You could cut off the flange on each side to make them fit in the long, wide slot.

A better solution would be to make a punch the correct size. You'll need some serious metal, steel would be preferred to make the punch and the die underneath. Then you can punch holes in formica, masonite, etc.
They do make panels for these. A quick google search for "automotive switch panel" turned up this-- though it's rather pricey. I suspect you could find them cheaper.

If you're planning to install these as switch controls in a panel, I think that Pete has the right idea: build a panel and then make the holes. You could possibly use thin sheet brass or sintra and a nibbler to get square holes, but a punch is maybe a better idea for clean holes perfectly lined up.
Here's some techniques for making "square" holes in sheet metal.

You can also search for "sheet metal panel punch" to see what's available but they are mostly kind of expensive. You might check some place like Harbor Freight Tools to see what they have.
Pete is correct - they are DPST.

I had found a different brand where two switches are glued together with s piece of plastic providing the space to accommodate the flanges. This would allow multiple switches to fit a rectangular panel but I was hoping to find a cheap pre-cut panel that was designed for switches like these to snap in. I would also need something to house the switches and panel.

In the past I have used Radio Shack project boxes with DPST and DPDT toggle switches but the attraction here is that the switches were very cheap. I hate to use up my remaining RS switches and the project boxes I have left are too small to accommodate these much larger switches.

The idea is for me to come up with a long tethered switch panel so I can remotely turn power to turnouts on and off while I do switching around the layout. With MTS I could leave the sidings power on but the noise of multiple loco sound systems and the accumulated amps on the various sidings could develop into a problem.

I like the idea of having a MTS wireless remote with me along with the ability to control power to the various sidings. In effect I could do the same thing when i switch to analog track power.

I would perhaps need two 7 position (sidings) switch panels tethered to selectively control power to the sidings.

Cheap pre-cut panels would be a nice option if I could find it.

I now have 20 cheap switches so I am looking for a way to put them to good use.

I have few tools anymore beyond hand tools like drills etc. and this is pretty much a one time project. I have $5 in the switches so anything that cost much more than that would be a non-starter.


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I have $5 in the switches so anything that cost much more than that would be a non-starter.
In that case, I return to my first suggestion - chop the side flange off so you can mount them side-by-side in a long slot. (Leave the flanges on one side at the ends.)
Any old saw should make short work of them.
In that case, I return to my first suggestion - chop the side flange off so you can mount them side-by-side in a long slot. (Leave the flanges on one side at the ends.)
Any old saw should make short work of them.
I agree, it would not be difficult to chop or grind the flanges off (I may end up doing that) but I can envision cutting or grinding my fingers in the process now that my eyes and dexterity are not what they used to be. These days I try to avoid cutting and grinding small objects.

I will probably procrastinate a year or so while I think about it.


If the bezels are thin plastic, you might be able to cut them off with side-cutter pliers or the little snips they sell for cutting models from sprues.
Thanks for the ideas. They give me options to think about.

Jerry - I have two suggestions - I put together a YouTube video recently that shows how to do this with a Harbor Freight multi-tool - you would need their smaller blade for your switches - you might even need to grind down the width a bit. See:

I have also had luck with 3d printing a rectangular hole of the needed size inside of a round plug - it is easy to drill a round hole and insert the plug into it.

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To me it looks as if you will need the flanges to prevent neighbouring connectors to touch.

Thanks to Dave and Peter I realized I probably need to borrow my jigsaw back from my son. I had given it to him a month or so ago because it had been years since I last used it.

The flanges may work to my benefit and that once I cut the rectangle or holes they should maintain the spacing between the switches.

Dave's videos showed me that this may work better than I had previously thought.

I have always liked the RadioShack project boxes. I will have to see if one of the remaining stores might still have some of those large project boxes.


MPJA.com can be a source for many electrical projects as they dump some very nice switches and other items monthly.
I was at a hobby shop and spotted these Atlas 215 Selectors:


Four single-pole, double-throw switches provide two-cab operation for four blocks. May be coupled together in any number for control of additional blocks without inter-switch wiring.

Excellent for dividing your railroad into 4 power districts for multi-train operation. Top postition gives power from power pack A. Center Position is Off. Bottom Position gives power from power pack B.

They are probably not rated for my application but I suspect they will work fine for temporary power to my sidings. Besides, they are small, expandable, and involve little effort on my part.

I bought a couple and will pair them together giving me the ability to control power to up to 8 sidings. If it works well I will probably go back and buy a couple more.

I figure I saved enough on the dealer's closeout of G Gauge to more than pay for these switches.

All I need now is a flat piece of plastic to screw or rivet a pair of these to.

Thanks for the suggestions. They were probably better than this but sometimes convenience wins.

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