Today I was in a house where we need to change all the dimmer modules since the old ones are triac dimmers and so flickering the new LED lights.

There's about 50 to change, all for new VPro Smart Multi Way (with the companions) and Standard 120w modules.

Unfortunately the house is filled with expensive screwless clear switches (similar to Wandsworth crystal) which have custom nuts for the knobs that then the nuts for attaching the front plate fit to, which means I can't use the nuts the new dimmers come with.

But these don't thread on the new modules properly? They do thread on other modules I have in the van, so do vpro modules really have a different thread pitch to everyone else? And would anyone know why? Normally not an issue but I often have to deal with overpriced designer switches like corston / wandsworth / buster + punch and this does end up a problem.

I managed to make it work by threading the new on first and then the old one (which partially threads on but not all the way) but it's not great.
 
Yeah, they certainly have a different thread to some, but maybe not all, other modules. Never been a problem for me as I've just been able to use the v-pro nut.
 
They are 10mm×1 thread - which I think is an uncommon thread to find on switches etc.
One of the things on my list is finishing the speed switch for the fan in the lounge. I did buy Fantasia's speed control, but the physical arrangement is not conducive to transplanting it into the Varilight grid.
Anyway, whether I use that, or as I plan, copy it but with the caps separate from the switch - I have the issue that the switch is 3/8" x 32tpi but the special nut to fit the Varilight grid module is M10.
So I've bought an M10 die and a 3/8 tap so I can see which works best - rethreading the switch I've bought, or rethreading the Varilight nut.
 
Yeah, they certainly have a different thread to some, but maybe not all, other modules. Never been a problem for me as I've just been able to use the v-pro nut.
Interesting, I've never encountered the thread issue before with anyone other than Vpro.

Ironically I've been pulling out older Doyle and Tratt dummy modules (Varilight parent company) which do indeed have the right thread pitch, so I'm guessing they changed for some reason. As well as a mixture of about 5 or 6 other brands which also have the correct pitch for these switches.
 
Varilight use a courser thread, which nut is it you need as they make them in various for different plates but you might have to approach them directly. The other pitfall you may face is spindle length, for some reason a varilight dimmer with a 5mm longer spindle to fit a Forbes and Lomax plate needs to cost 5 times more than a normal one. Incoming dimmer module disassembly...
 
Varilight use a courser thread, which nut is it you need as they make them in various for different plates but you might have to approach them directly. The other pitfall you may face is spindle length, for some reason a varilight dimmer with a 5mm longer spindle to fit a Forbes and Lomax plate needs to cost 5 times more than a normal one. Incoming dimmer module disassembly...
There's almost no chance of finding the correct replacement to fit a vpro module haha, these are special switches.
IMG-20241217-WA0009.jpg


I already encountered another weird threaded hamilton intermediate module (maybe like M6?) which can't be replaced too, the stalk doesn't even fit through the nut so I'm going to have to juggle some of the existing switches which don't need dimming so I can poach the correct size nuts from them.

IMG_20241217_154718.jpg


As for spindle length I've been lucky that the knobs for these plates are very shallow, and I just stuffed a tiny bit of paper at the back of the hole to stop them pressing on too far. One of the last guys decided to just glue the knobs on which was fun to find out.
 
Varilight use a courser thread, which nut is it you need as they make them in various for different plates but you might have to approach them directly.
I've found them fairly heloful.
The other pitfall you may face is spindle length, for some reason a varilight dimmer with a 5mm longer spindle to fit a Forbes and Lomax plate needs to cost 5 times more than a normal one. Incoming dimmer module disassembly...
Ah yes, the modules made for grid systems have a longer spindle as itvhas to reach out from inside the grid unit rather than being mounted on a flat plate.

For good measure, they sell the moulded units for different grid systems (so you can, for example, fit some rotary switch in a grid) but don't include the special nuts needed. They got me some, but it tookna while as I think they had to have some sent from the factory.

Reminds me of Standards - https://xkcd.com/927/
 
I've found them fairly heloful.

Ah yes, the modules made for grid systems have a longer spindle as itvhas to reach out from inside the grid unit rather than being mounted on a flat plate.

For good measure, they sell the moulded units for different grid systems (so you can, for example, fit some rotary switch in a grid) but don't include the special nuts needed. They got me some, but it tookna while as I think they had to have some sent from the factory.

Reminds me of Standards - https://xkcd.com/927/
Yeah I had some given to me the other day from Zano, nice but they give you 9 different adaptors and you'll only ever need one so have to chuck the rest, seems like a massive waste.
 
Have found myself in a similar situation using click minigrid stuff recently. The minigrid specific dimmers have a coarser thread than the other click dimmer modules meaning no interchangeability. Wasn't the end of the world, but an annoyance in the moment!
 
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Am I going crazy or are VPro dimmers threaded differently?
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