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justin1985

Long thin screws for microswitches (etc)

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It seems really difficult to find screws that are both long and thin enough to attach things like microswitches and PCBs to baseboards. Microswitches seem to have standard mounting holes of something like M2.5 size, but need a screw at least 10mm long to pass through them and into the baseboard - it seems incredibly difficult to find screws (as opposed to bolts) that will fit through these holes! 

 

I found some selection boxes of black self tapping pan head M2 and M2.6 screws on eBay, but you only get a handful as long as 10mm in the box, and they seem very poor quality (Philips head strips very easily). There doesn't seem much else out there which will screw into wood. 

 

What else do people use to attach things like microswitches? 

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2 minutes ago, justin1985 said:

It seems really difficult to find screws that are both long and thin enough to attach things like microswitches and PCBs to baseboards. Microswitches seem to have standard mounting holes of something like M2.5 size, but need a screw at least 10mm long to pass through them and into the baseboard - it seems incredibly difficult to find screws (as opposed to bolts) that will fit through these holes! 

 

I found some selection boxes of black self tapping pan head M2 and M2.6 screws on eBay, but you only get a handful as long as 10mm in the box, and they seem very poor quality (Philips head strips very easily). There doesn't seem much else out there which will screw into wood. 

 

What else do people use to attach things like microswitches? 

How many do you need...

https://www.amazon.co.uk/Sourcingmap®-Cross-Countersunk-Tapping-Fastener/dp/B01D9JE4XM/ref=sr_1_31?keywords=m2+screws+15mm&qid=1575626597&sr=8-31

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Hi Justin.

 

How about using some threaded rod with a washer and nut instead? It normally comes in 12" lengths.

 

J.

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1 minute ago, -missy- said:

How about using some threaded rod with a washer and nut instead? It normally comes in 12" lengths.

 

 

That certainly seems easier to find Julia, but I'm trying to attach microswitches directly to the bottom of baseboards to be triggered by the movement of already fitted Turnout Mechanisms, so I can't really fit nuts on the other side! I guess the real solution would have been to have build a more elegant turnout mechanism with switches fitted integrally - but you know, I tend to end up bodging things! 

 

6 minutes ago, TheQ said:

 

Those look ideal - I hadn't thought to look on Amazon. The selection of far eastern bits and bobs usually seems very similar on eBay and Amazon, but it seems like Amazon has a lot more choice! Cheers

 

J

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9 minutes ago, justin1985 said:

It seems really difficult to find screws that are both long and thin enough to attach things like microswitches and PCBs to baseboards. Microswitches seem to have standard mounting holes of something like M2.5 size, but need a screw at least 10mm long to pass through them and into the baseboard - it seems incredibly difficult to find screws (as opposed to bolts) that will fit through these holes! 

 

I found some selection boxes of black self tapping pan head M2 and M2.6 screws on eBay, but you only get a handful as long as 10mm in the box, and they seem very poor quality (Philips head strips very easily). There doesn't seem much else out there which will screw into wood. 

 

What else do people use to attach things like microswitches? 

 

I tend to mount microswitches onto plates to allow fine movement.  So the plate will either take a nut behind it, or can be tapped to take the thread.

 

However, if wanting self-tappers, suggest looking at specialist suppliers, eg:

https://www.kayfast.co.uk/view-product/POZI-PAN-TAPPING-SCREW-DIN-7981C-Z-A2-ST-ST

 

 

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Try putting 'japanned wood screws' into your favourite search engine.

 

I came up with something suitable.

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Try not to use counter sunk heads directly onto the micro switch as the conical head puts the plastic under pressure 

 

pan head is best 

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RC servo mounting screws work well. The socket head types from modelfixings.co.uk I have found to be particularly good.

 

Cheers

idd

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12 hours ago, Junctionmad said:

Try not to use counter sunk heads directly onto the micro switch as the conical head puts the plastic under pressure 

 

pan head is best 

 

Exactly the opposite.

CSK heads centralise the hole in the microswitch and impart a degree of positive location, if you're tightening the screw so tight that it distorts the microswitch housing you've gone way too far. Unless the thread is the same size as the hole, the PHP does not give this positivity.

 

Mike.

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I have seen the effect of the conical forces at work. I would not advise the use of countersink screw heads. In the intended field of use , which I am familar with , they would ALWAYS use either pan head or socket head machine screws. The positioning keeping is achieved by a combination of the clamp load and the use of proper diameter screws . 
 

You would never see countersunks being used. 
 

 

  • Agree 1

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I have seen the effect of the conical forces at work. I would not advise the use of countersink screw heads. In the intended field of use , which I am familar with , they would ALWAYS use either pan head or socket head machine screws. The positioning keeping is achieved by a combination of the clamp load and the use of proper diameter screws . 
 

You would never see countersunks being used. 
 

 

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Track pins are OK for many such applications. Hornby pins are thicker than Peco and some others.

 

I think I got my tiny screws from Peters Spares or New Modellers Shop. Its been a while since I bought them and I have plenty left.

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