Question Fan Screws

[Mantrid-Drone]

When you get a case it usually comes with fan mounting screws. Typically I've found these are 8mm long with an 8mm flat head for mounting the fan through holes in the outer case chassis and rear or side panels. Those holes are 7mm in diameter, at least in the three cases I have experience with.

With two of the cases (Corsair) you're supplied with rubberized anti-vibration grommets to line those holes. So the heads are effectively made even wider.

Fans inside the case ie. inside the front panel or on the CPU cooler may use the same size screws but can also use something slightly different. Screws for mounting accessories like finger grills or filters tend to be 8mm too but with a slightly countersunk 6.4mm head.

Here's the problem: I'm having difficulty (UK) in finding 8mm wide flat head fan screws of any length. They all seem to use the 6.4mm countersunk heads whether they are 8mm, 10mm or 12mm long.

These are unsuitable for mounting through the case because they're less than 7mm hole diameter.

You could use a washer but that would have to be designed to receive countersunk screws inevitably meaning they stand proud of the case. You'd have to change every screw set to match or it would look amateurish and probably would not look good anyway.

I have found 8mm/8mm flatter head screws with shallower countersinking in a few places but what I really need are 10mm/8mm genuine flat head fan screws. The case manufacturers supplied 8mm long ones are fine but you only get a limited number. If you're mounting the fan though a metal or plastic framed case filter it means the fan will be held in place by just a couple of millimeters of the 8mm screw thread.

Obviously there are alternatives like using thin plastic filter sheet material. I've done that before but it is a compromise when what you actually need are either 10mm or 12mm long fan screws with an 8mm flat head rather than 6.4mm.

Where can you get them? Ebay and Amazon sometimes list fan screws as flat head but when you look at the listing you see that, at best, they're shallower countersunk ones or not flat heads at all.

Surely somebody supplies 10mm or 12mm genuine flat head fan screws.

 

[Mr Evil]

You might be having difficulty because "flat head" is used to describe countersunk screws. Perhaps you mean "pan head"? The terminology is a little fuzzy.

When I need to attach a fan without a grille, or otherwise don't want to use countersunk screws, I use M4 machine screws long enough to go all the way through the fan, held on with nuts. Though slightly more fiddly to install than dedicated fan screws, they are widely available with any head style, in any length, and avoid the horrible sound of plastic crying out in pain from being sliced into by thread-cutting screws.

 

[Mantrid-Drone]

That is an idea which would certainly work so thanks for that.

The terminology of the head shape is indeed "fuzzy" but, in the UK, when I used the term "pan head fan screws" and variations on that to search places like Ebay and Amazon(UK) it was only US sources that produced any results.

Some could supply 8mm/8mm screws ie. the same as came with the case but 10mm/8mm, 12mm/8mm or their US/Imperial equivalents were absent from any results. There was also the additional shipping charges to the UK to consider too. Much as I want the correct screws I'm not paying three times their value just to get them across the pond.

That's when I tried the term "flat head" instead. With their shallower counter sinking they will do the job but finding a UK supplier even for those who can confirm the heads of the 10mm or 12mm self-tapping fan screws they're selling are 8mm rather 6.4mm is proving difficult too.

 

[mindless1]

What case is this that has 7mm holes? I admit I've never measured my case(s) fan mount holes but all cases I recall, worked with standard fan screws.

fan screws for sale | eBay

Find great deals on eBay for fan screws. Shop with confidence.

www.ebay.co.uk

 

[Mantrid-Drone]

Corsair Carbide 200R case.

The fan/filter mounting holes in the side, top, bottom and rear panels are definitely 7mm diameter because one of the things I've done with this build (actually an upgrade build) is to use blanking inserts and 7mm ones are perfect.

With Corsair being a US manufacturer I'd guess they're nominally 1/4" which is 6.35mm. If the fan mounting holes are press cut rather than drilled it would not be surprising to find they're closer to 7mm in diameter.

The used holes are lined with rubber grommets which decrease the diameter of course but if you use the 6.4mm flat head/shallow countersunk screws most commonly listed and supplied as fan screws they are, fairly obviously, not wide enough and can easily be screwed 'through' the grommet.

This is surely the very reason why Corsair provide 8mm wide flat headed 8mm long fan screws. But they only supply 4 spare ("long") ones + grommets specifically for the second front mounted fan position (fan not supplied). They're not actually longer they just have a thinner profile head and so more screw thread length.

These are not standard self-tapping screws either, they're designed for the case's pre-threaded mounting positions so have a much finer thread pitch and pitch diameter than the usual self-tapping fan screws.

The other fan positions (bottom intake, two top exhaust and two same side panel intakes/exhaust) are not supplied with the same size fan screws.

Corsair instead supply 16 more typical pitch self-tapping fan screws but, again, the same 8mm diameter flat heads. However the heads are thicker profile so the actual screw length is less. This means for mounting a fan through a metal framed filter the screws are barely long enough to do the job.

Hence my search for 8mm diameter flat or almost flat headed 10mm or 12mm self-tapping fan screws or even just 8mm long ones with the thinner profile head like the 4 Corsair supplied ones.

Still no joy.

 

[EliteRetard]

Not sure why your thread is the one to get me online again...your lucky day I guess.

This isn't hard to find in the US (with the right terms), but for the UK I didn't know where to look except one of those Chinese websites.
Anyway with a short search I think I found an option that will work on AliExpress, though it's hex and not self tapping:

0.63US $ 20% OFF|5/10/50pcs Cm M1.6 M2 M2.5 M3 M4 M5 M6 M8 304 Stainless Steel Hex Hexagon Socket Ultra Thin Flat Wafer Head Allen Cap Screw Bolt - Screws - AliExpress

Smarter Shopping, Better Living! Aliexpress.com

www.aliexpress.com

I believe the standard computer fan (any size) uses an M5 size screw. If I have this incorrect let me know and I'll look for the correct option.

In fact I'll keep looking for a few more minutes, maybe I'll find a Phillips self tapping version.
If you don't mind a "dome head" design those are super common, in fact here's one of those real quick:

1.97US $ 10% OFF|20pcs M5 10mm/12mm/16mm/20mm/25mm/30 GB845 304 Stainless Steel Cross Recessed Pan Head Screws Phillips Self tapping Wood |Screws| - AliExpress

Smarter Shopping, Better Living! Aliexpress.com

www.aliexpress.com

 

[EliteRetard]

There are some black versions (M5 Phillips truss) available too:

1.13US $ 11% OFF|50pcs/25pcs M3 M4 M5*l Steel With Black Phillips Truss Head (cross Recessed Mushroom Head) Self Tapping Screws|Screws| - AliExpress

Smarter Shopping, Better Living! Aliexpress.com

www.aliexpress.com

 

[Mantrid-Drone]

I'll have a look at those - thanks.

My preference is for black Philips cross head rather than Allen cap or I'd have to replace all the existing Philips head screws. I've ignored Allen cap listings in my searches but those thin pan head ones are shown as "dk" (which appears to mean the max. head diameter) of 8.8mm which is much more like what I've been looking for.

Standard fan screws are reported as having a 5mm major diameter ie. widest diameter but I've not actually found any definitive dimensions for such screws except in Ebay listings. Depending where you look the US/Imperial size listed equivalent fan screws are being sold as 7/32" which converts to 5.5mm.

M5 are 5mm major diameter with a 0.8 mm pitch and require a 4.2mm hole to self-tap apparently.

The standard fan mount holes in the fan's own mounting frame are variously reported as being between 4mm and 4.8mm so any screw with a minor diameter of around 4mm, like a M5, are either going to fit very tightly or will self-tap the plastic fan frame holes without much effort.

I'm not keen on using nuts to secure such screws though. I suppose there are quality plastic nuts that could be used but I do not like the idea of small metal nuts securing anything inside a PC case. One of those working loose, even a plastic one, and dropping into the PC is too much of a damage risk. That potential is another reason why I wanted to find a wider head fan screw than the 6.4mm standard ones particularly for the top fan mount positions.

 

[EliteRetard]

So will an M5 work, threading itself into the plastic fan frame? If so, what is your opinion of the black Phillips truss heads in my last post?
If you want a really flat wide head there's these more expensive specialty screws:

12.03US $ 14% OFF|20Pcs M5 Big Falt Thin Countersunk head Cross Phillips Screws Foot pad notebook Screw bolt Black zinc Length 4mm 10mm|Screws| - AliExpress

Smarter Shopping, Better Living! Aliexpress.com

www.aliexpress.com

If M5 is not the correct size I can try to look for something else. Are there other websites that ship to you that I could browse?

 

[Mantrid-Drone]

M5 ones should work but I can not confirm that yet.

In the last link you provided the 'mushroom' head Philips screws are the best solution I've seen so far. I can probably find those in the UK OK too.

I know I can find ordinary chrome M5/10mm and 12mm ones with thin-ish pan heads at a local hardware shop but they're not black and ordinary screw head not Philips.

Surely if Corsair supply black, Philips cross head self-tapping screws with 8mm thin pan or flat heads or whatever they're correctly called somebody somewhere in the world must manufacture them. I can not believe these are custom made or that they're just supplied in one length either.

 

[EliteRetard]

M5 ones should work but I can not confirm that yet.

In the last link you provided the 'mushroom' head Philips screws are the best solution I've seen so far. I can probably find those in the UK OK too.

I know I can find ordinary chrome M5/10mm and 12mm ones with thin-ish pan heads at a local hardware shop but they're not black and ordinary screw head not Philips.

Surely if Corsair supply black, Philips cross head self-tapping screws with 8mm thin pan or flat heads or whatever they're correctly called somebody somewhere in the world must manufacture them. I can not believe these are custom made or that they're just supplied in one length either.

The website I linked does appear to ship to the UK (for free), which is why I chose it.

Here in the US it's not to hard to find odd screws, so I'm just copying the parts from one website to another. The hard part here is that I'm not exactly sure what I'm looking for or what variables you're working with... kinda narrowing it down as I throw out options. Black, Phillips, M5, 10-12mm long, 8+mm head flat inside face (haven't determined ideal head type yet). I'm not sure if you need self tapping, since fans have pre-drilled holes even a machine screw of the right size should work.

 

[WelshBloke]

Google Search

That sort of thing? (Sorry about the uber Google link!)

 

[EliteRetard]

Google Search

That sort of thing? (Sorry about the uber Google link!)

It sounds like his case uses greatly enlarged screw holes that are incompatible with any standard fan screws.
His case requires a different type/size/shape screw, and they only included enough of those screws to mount a single fan.
The trick here is to deduce not only the type of screw they used, but a location where he can acquire them in the UK.

I only now realized I could do some research on the case itself to see if I can determine what they included.
In fact that's so obvious that I can't even form the words to my own stupidity...it literally hurts my brain.

I need to rest now, I'll pursue this new line of investigation when I wake.

 

[Mantrid-Drone]

Thanks for the help/suggestions.

I'll see if I can find an online copy of the Corsair Carbide 200R manual as that depicts the screws supplied better than I can describe.

Found; page four of the PDF is the relevant one but you can also see the 7mm (1/4") 120mm/140mm fan mounting holes I'm talking about in the top and side panel pictures :-

https://www.corsair.com/corsairmedia/sys_master/productcontent/49_000178_revAA_200R_InstallGuide_EFGISRChJ.pdf

Welshbloke's Amazon link above shows, mostly, what I'd call standard fan mounting screws - flat but countersunk. But the first hit, the chrome only Startech M5 ones are interesting.

Their heads are the standard diameter ie. too small 6.4mm but otherwise very close to the Corsair supplied thin head shape. They are normal self-tapping screws too unlike the Corsair thin head 'long' screws which are fine pitch, as said, and meant to be used for the pre-threaded front mounting positions.

It is seen best in the second picture used in the listing. From some angles the screws look countersunk but those lying side on clearly have the same thin flat head I'm looking for.

Now 'all' is needed is to find them in black, with a wider head and ideally slightly longer.

EDIT

Just found this PC screw set on Amazon:-

https://www.amazon.co.uk/dp/B07BVVPZMD/ref=psdc_5141746031_t2_B0002AFTD6

the "Fan Screws" are the standard type but the ones show on the box lid as M3 x 8 do appear to have the right thin profile flat head. Again they're probably still only 6.4mm diameter but it does suggest that thin profile flat Philips head screws are not a niche design.

 

[EliteRetard]

After some research I may have found an image of the screw you're looking for.

https://flic.kr/p/aiihKm

If this is what you need, that's a shoulder screw. Definitely a more specialized screw, but shouldn't be impossible to find.
Turns out I am going to be more busy this weekend, so I may not have a lot of time to find the perfect one.
However here's what I could find with a quick search:

McMaster-Carr

McMaster-Carr is the complete source for your plant with over 595,000 products. 98% of products ordered ship from stock and deliver same or next day.

www.mcmaster.com

Ultra Low Profile Shoulder Screw

Ultra Low Profile Shoulder Screw, Shi Shi Tong Product Long Screw Bolt, Shoulder Screw, Titanium Screw, Small Screw, Etc.

www.sstls.com

Shoulder Bolts and Shoulder Screws - Grainger Industrial Supply

Use shoulder screws from Grainger to keep engines and machinery running at top performance. Check out a large shoulder screw selection today!

www.grainger.com

Shoulder Screws Archives | AMPG Shoulder Screws

AMPG shoulder bolt is made in one operation on state-of-the-art Swiss Lathes using precision ground DFARS compliant material.

ampg.com

Oh hey this one looks promising:

This product is no longer available.

This product is no longer available.

www.alibaba.com

I was gonna say, I'll have to try to find the right one that can ship to the UK...but that last one I just ran into looks exactly right.
I gotta go for now, but maybe this will be the springboard you need to launch you toward your goal.

 

[Mantrid-Drone]

I sort of resigned myself to having to use a less satisfactory alternative. I'd settled on trying some M5 0.8 fine pitch countersunk 12mm ones which have a wider flat head.

I found them on Ebay and hoped that the countersinking would not leave the head proud of the case and the M5 thread would self-tap well enough to hold the fan. After all that is what the longer Corsair screws for the front mounts appear to use.

But now there is a new screw type search branch I can can follow. Thanks for that. The shoulder of that last one is short enough that it would still probably work OK but the threaded part has to go through a metal filter frame before engaging the fan mount. There is an answer for that ie, drilling out the filter mounting holes but I really wanted to avoid DIY modding solutions.

Please do not let this matter take up any more of your time, you've been more than helpful. But, of course, if you happen to come across any black, Philips cross-head, 8mm diameter, 10mm - 12mm long, low profile flat/pan headed self-tapping screws I'd still like to know.

 

[EliteRetard]

Well if the shoulder screws are not the same as the ones corsair included, then they can be ignored (more expensive/specialized).
I thought I had found a picture of the screws included with the case and thought those were the ones you were looking for.

I don't mind researching a bit on my free time...
This is kinda like a double treasure hunt, trying to determine what the original screws looked like (so I can identify them) and then a location in the UK to buy them.

 

[Seba]

What happened with the 16+4 fan screws that came with the case?

 

[Mantrid-Drone]

If you look at the PDF page you'll see they are shown as "short" screws principally because the head is of a thicker profile. Whilst they do have the same 8mm diameter head as the other "long" screws they're effectively shorter. When using a metal/plastic frame fan filter between the fan and the case the screw thread holding the fan mount is minimal. Those self tapping screws have a pointy tip (2mm?) too so only hold the fan from the point where widest part of the thread starts to bite.

That is the problem - the length of the screws provided are not adequate.

My other desktop uses the same Corsair case and fan positions and that's when I realised this could be a potential problem. The screws themselves are not exactly marvels of manufacturing consistency either and what I found was that using the supplied ones I could pull the mounted fan off them with very little force.

When I used standard, effectively longer, third party 6.4mm diameter headed screws I found you could pull the screws through the case mount points very easily too.

In the end because I did not have a better solution I used the supplied wider head 'short' screws and applied super-glue strategically to help support the fan. Four years on there have been no problems but it was not an ideal fix. Hence by interest in this matter.

I need the filter behind the exhaust fan mounts at the top of the case because otherwise the open lattice design has no protection against dust ingress when the PC is off.

If I used thin PVC filter material there wouldn't be a problem but to mount even that the full length of the case you'd need something under it to keep it in place ie. nuts + washers. Additionally it seems stupid using an exhaust fan with good air volume shifting stats only to interfere with its extraction performance by partially blocking the vents more than necessary.

The metal frame filters I use appear to filter dust well enough and judging from some simple tests I did with tissue paper sheets attenuate the exhaust air venting less than the PVC filter sheet I tried.

 

[StefanR5R]

If I used thin PVC filter material there wouldn't be a problem but to mount even that the full length of the case you'd need something under it to keep it in place ie. nuts + washers.

There are also some filters with magnetic frame (either an entirely magnetic frame which is thin and flexible, or a plastic frame with four or eight little magnets embedded). They stick well enough at the outside of most steel cases.

 

[Mantrid-Drone]

I've seen and considered those for the non-fan mounted top position and the side vents too.

But you can not use them behind the top fan as needs to be done. I suppose you could mount them on the outside as a crude solution.

I also momentarily considered using magnets to secure a custom cut sheet of PVC filter material across the whole open top ie. honeycombed section. But I didn't like the idea of using loose magnets inside a PC.

Ideally Corsair should be providing a slot in filter for that part of the case because dust ingress from the top, even with filters in place, is significant. Despite the postive internal air pressure (3 x intakes/2 exhausts excluding 2xCPU, PSU and 2xGPU fans) all the extra filters I've used still haven't prevented the inside of the case being coated in a fine layer of dust over 4 years.

Most of that must have come through that honeycomb open top. The filters I used there, periodical cleaned, are testament to that.

 

[StefanR5R]

Computer case filters don't filter fine dust.
If you want that, you'd need something like the allergen filter of a vacuum cleaner. You do the math what kind of power the intake fans need then. :-)