# Fixture Screw Size



## RePhase277 (Feb 5, 2008)

Probably metric. M3.5 or M4.


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## 3DDesign (Oct 25, 2014)

Takideezy said:


> Anyone know the screw size (pitch and diameter) that are being shipped with imported lighting fixtures? It's larger than 6-32 and smaller than 8-32.
> 
> Last week I had a call to mount 12 wall sconces and due to variations in the wall finish, some of the screws coming through the box bar were to short to engage the two threaded balls nuts that retain the fixture.
> 
> ...


I wish I knew the size, metric or English. It seems to vary.
Here's how I solved it. I hope this makes sense.
I use longer 8/32 to mount the box bar to the box. Before I install the bar, I put the longer 8/32 through the bar and install an 8/32 nut on the back side. I tighten it to bar and back it off about a full turn. 
Install the bar as you normally would, stopping at the surface of the wall. The 8/32 nut will prevent the bar from pushing back into the wall.
If the 8/32 doesn't turn properly, your nut is too tight. If the bar flops around, the nut is too loose. After trying this a couple of times, you'll get it to work on ever light fixture. I do the same thing with receptacle and switches if the wall opening is too large for the yoke, but use 6/32 nuts.


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## OldMasterTech (Mar 12, 2014)

4 mm almost fits your description - #8 is 3.96875 mm


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## trentonmakes (Mar 21, 2017)

Takideezy said:


> Anyone know the screw size (pitch and diameter) that are being shipped with imported lighting fixtures? It's larger than 6-32 and smaller than 8-32.
> 
> Last week I had a call to mount 12 wall sconces and due to variations in the wall finish, some of the screws coming through the box bar were to short to engage the two threaded balls nuts that retain the fixture.
> 
> ...


Those are the sizes i carry as well. I probaly would have done the same in that situation. Havent come across it, yet.


Texting and Driving


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## telsa (May 22, 2015)

If you have to touch imported lighting fixtures -- demand a price bump.

The OP establishes why.


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## Bird dog (Oct 27, 2015)

telsa said:


> If you have to touch imported lighting fixtures -- demand a price bump.
> 
> The OP establishes why.


AHJ may require the fixture to be "Listed".


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## JohnJ65 (May 8, 2008)

I've been finding the same thing, the fixture to box screws will strip out if its a Bakelite box and they wiggle if it's a steel box. 

I've been throwing them straight in the trash and using my own 8-32's. If it's the screws that the ball nuts go to on a cross bar I will leave them on there but fasten the cross bar to the box with a true 8-32. 

I'm finding it on the more expensive fixtures too.


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## trentonmakes (Mar 21, 2017)

JohnJ65 said:


> I've been finding the same thing, the fixture to box screws will strip out if its a Bakelite box and they wiggle if it's a steel box.
> 
> I've been throwing them straight in the trash and using my own 8-32's. If it's the screws that the ball nuts go to on a cross bar I will leave them on there but fasten the cross bar to the box with a true 8-32.
> 
> I'm finding it on the more expensive fixtures too.


Is there another way to do it?
Maybe I misunderstood OP, but that is exactly how I do it[emoji106]

I dont use bakelite boxes though

Texting and Driving


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## JohnJ65 (May 8, 2008)

trentonmakes said:


> Is there another way to do it?
> Maybe I misunderstood OP, but that is exactly how I do it[emoji106]
> 
> I dont use bakelite boxes though
> ...



I don't do much new construction but do get a boat load of work from a local lighting store, so I get stuck with whatever box is behind the fixture I'm taking down.

If it's a fan install that Bakelite box is going in the trash too.


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## macmikeman (Jan 23, 2007)

So the metric screws don't fit, well, I notice the foreign made blue nail on boxes that have replaced the Union company boxes I used to get , the screw *Holes* are not 8-32 anyhow. Use a sheet rock screw with course threads and screw the code book, those old farts haven't put on a toolbag in twenty five years who author it.


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## active1 (Dec 29, 2009)

We always just called em metric #8's.
Had a handful left over from other jobs.


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## EJPHI (May 7, 2008)

I ran into this too.

Check the box the fixture came in.

Does it say made in China?

If yes you are dealing with a manufacturing system that has found a way to make screws so cheap and crappy that normal english and metrics sizes don't really apply. Those screws and nuts in that batch of fixtures will be happy together. But they won't play well with others.

If I need different length or better quality, I use my own hardware and pull out my tap and die set. Those cheesy super champ type crimpers will cut and chase 8-32 SS thread just fine and brass is very easy.


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## varmit (Apr 19, 2009)

I call fasteners like this "smetrics"(SAE + Metric). They are screws that don't seem to fit any normal thread. 

Some of the screw heads, on Asian made equipment, are made so that no known tool will fit properly. I was recently working on some LARGE industrial machines, that had some terminal screws that neither Phillips, Pozidrive, JIS or a strait blade screwdriver would fit without slipping or caming out.


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## cpprioli (Apr 9, 2019)

The actual size is in fact a metric size -- 3.5mm diameter x 0.6mm pitch (3.5-0.6), and they are VERY hard to find. I too use standard machine screws of adequate length, and I usually place a nut on each side of the bar, on each screw. This allows for quick exposed length adjustment by simply loosening the outer (jam).nut, repositioning the screw as needed for the required exposed length, and securing it there with the two nuts locked down against opposite faces of the bar. It's ugly, but it works... :wink:


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## 99cents (Aug 20, 2012)

They’re #10 Tek screws.


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## CoolWill (Jan 5, 2019)

RePhase277 said:


> Probably metric. M3.5 or M4.


This guy gets it.


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## HackWork (Oct 2, 2009)

CoolWill said:


> This guy gets it.


That was 99cent's other account.


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## 99cents (Aug 20, 2012)

HackWork said:


> That was 99cent's other account.


Are you still pouting from the last time I kicked your ass?

Why are you clogging up an electrical thread with your garbage?


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## CoolWill (Jan 5, 2019)

HackWork said:


> That was 99cent's other account.


Well, when he's right, he's right.


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## HackWork (Oct 2, 2009)

99cents said:


> Are you still pouting from the last time I kicked your ass?
> 
> Why are you clogging up an electrical thread with your garbage?


I’m “clogging up an electrical thread” that died in 2017?

I don’t understand what you mean about kicking my ass, when did that happen?

Did you have a bad day today? Did someone tell you that your purse clashed with your shoes?


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## HertzHound (Jan 22, 2019)

When are they going to start shipping them with the three sided screw heads. Like the ones in the McDonald’s toys. WTF is with those toys that they don’t want you to take them apart? I’ve never seen a tamper profs screwdriver that would fi a McDonald’s toy. 

That has got to be some sort of Asian global conspiracy thing going on. Probably something in the toys secretly brainwashing toddlers!!!


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## Bird dog (Oct 27, 2015)

HertzHound said:


> When are they going to start shipping them with the three sided screw heads. Like the ones in the McDonald’s toys. WTF is with those toys that they don’t want you to take them apart? I’ve never seen a tamper profs screwdriver that would fi a McDonald’s toy.
> 
> That has got to be some sort of Asian global conspiracy thing going on. Probably something in the toys secretly brainwashing toddlers!!!


The sinister thing is you can't tell their a fry short of a happy meal until they grow up. :shifty:


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## 99cents (Aug 20, 2012)

HackWork said:


> I’m “clogging up an electrical thread” that died in 2017?
> 
> I don’t understand what you mean about kicking my ass, when did that happen?
> 
> Did you have a bad day today? Did someone tell you that your purse clashed with your shoes?


Go away, troll. The adults are talking.


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## HackWork (Oct 2, 2009)

99cents said:


> Go away, troll. The adults are talking.


 I will out adult you any day of the week.


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## lighterup (Jun 14, 2013)

While we're on the discussion of light fixtures that have 
the Canadian tag on them. Am I alone here on this? 
I hate assembling these. It's like the logic behind their 
construction is all azz backwards.


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## brian john (Mar 11, 2007)

I hung a chandelier and the screws that came with it were crap cheap azz Chinese junk, I trashed them and put some higher quality screws I had.


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