Rad Screws Size??

[ScottALot]

I don't want a screw that will puncture my radiator (obviously) but I want it to be long enough to go through my 38mm fan, case, and have enough at the end to hold onto my radiator. FrozenCPU recommends a 30mm screw for a 25mm fan, but with 38mm fans, they offer both 40 and 45mm screws. I use a GTX 360 Radiator which uses M4 screws. My question is: for a 38mm fan, 40 or 45mm screws? 40 seems almost a bit short and 45 seems excessive! For 25mm fans, I think 5mm extra sounds good, but with 38mm fans, choosing between 2mm and 7mm extra seems like a dangerous choice. HELP!

[Geezer]

I don't want a screw that will puncture my radiator (obviously) but I want it to be long enough to go through my 38mm fan, case, and have enough at the end to hold onto my radiator. FrozenCPU recommends a 30mm screw for a 25mm fan, but with 38mm fans, they offer both 40 and 45mm screws. I use a GTX 360 Radiator which uses M4 screws. My question is: for a 38mm fan, 40 or 45mm screws? 40 seems almost a bit short and 45 seems excessive! For 25mm fans, I think 5mm extra sounds good, but with 38mm fans, choosing between 2mm and 7mm extra seems like a dangerous choice. HELP!

Take a look at the radiator and see if it has a gap between the shroud area where the screw holes are and the fins. I don't have one of those radiators but from looking at pictures it seems that it might. If it does, measure the distance between the outside of the shroud and the fins (ie. include the thickness of the shroud material) and then subtract 1 or 2mm for the case material thickness. Sounds to me like you should have enough room for the longer screws, but that's based entirely on the assumption that the gap between shroud and fins exists. 5mm is really not a lot.

Or, just wait for someone else with one of those rads to come around and comment...shouldn't take long around here ;D

[Waterlogged]

Never been a fan (pun not intended) of the super long screw mounting method. Instead, I prefer to use shorter screws and modularize the assembly like this.

http://www.xtremesystems.org/forums/attachment.php?attachmentid=82091&d=1216189933

[Martinm210]

Depends on the gasket, but I'm pretty sure you need 45s.

Always check with that first screw and make sure they are all the same length too. You could always cut/grind off a few mm if needed.

I poked a hole in an MCR320 a few years back...not fun, but it is fixable with a soldering iron.

[BringerOdeath]

I was wondering a similar thing, so this answered my question. By the way, where can I buy gaskets for my rads??

[SlackerXL]

i've had many 38mm fans that would mount perfectly with M3/4 40mm screws
as long as the threads on the rad are intact.

I'am almost certain that the 45mm ones will touch/ if not penetrate, the rad fins
unless you use a fan grill and/or thick rubber gasket.
to check for yourself before ordering.
insert a plastic card, piece of carton or something around 1-2mm thick
underneath the radiator threads to ensure a safe distance from the fins
cut the one edge of a q-tip and insert it through the fan screwhole
just like you'd use a screw to mount it.
and mark the plastic rod at the appropriate length leveled to the fans frame.
that should give you a rough estimate of the screw length you need.

[Alexandr0s]

Waterlogged, mind explaining how you got those screws into place? Because it would significantly benefit my case :D.

[zsamz_]

shortest screws always lol
i killed 2 rads cause of 2mm xtra long screws lol

[Church]

"killed" should be replaced with "damaged". As they most probably can be fixed. If not with soldering by yourself, then eg. at some place that fixes car radiators.

[Waterlogged]

Waterlogged, mind explaining how you got those screws into place? Because it would significantly benefit my case :D.

Well, that's a 38mm shroud mounting a Yate Loon to a PA120.1, which is a little different than how I'd do it on a case. First I mounted the shroud to the PA using 6-32 x 3/8" Allen head screws, I then used 10-32 x 3/8" (overkill btw) Allen head screws to hold the fan to the shroud. I was able to turn the 10-32 with a ball end Allen wrench.

http://a.imageshack.us/img52/2849/220pxallenwrenchwithbal.jpg

These Allen wrenches allow up to a 25° angle and are still capable of tightening the screw.

For the setup scott is planning on using, I would keep the rad side the same and probably hot glue some #6 or #8 nuts to the fan where the heads of the 10-32's are in my pic.

[Alexandr0s]

Thanks :).

[ScottALot]

i've had many 38mm fans that would mount perfectly with M3/4 40mm screws
as long as the threads on the rad are intact.

I'am almost certain that the 45mm ones will touch/ if not penetrate, the rad fins
unless you use a fan grill and/or thick rubber gasket.
to check for yourself before ordering.
insert a plastic card, piece of carton or something around 1-2mm thick
underneath the radiator threads to ensure a safe distance from the fins
cut the one edge of a q-tip and insert it through the fan screwhole
just like you'd use a screw to mount it.
and mark the plastic rod at the appropriate length leveled to the fans frame.
that should give you a rough estimate of the screw length you need.

On the topic of the plastic card... don't think that will save you from rad puncture all the time. I don't remember where from, but some guy did that test and ended up puncturing his radiator anyways. Another punctured his radiator through a puncture guard :yepp:

EDIT: And I think I'm going to go with the 40mm and hope for the best. I'd rather not risk puncture and because I'm using a 360mm radiator (12 screws on one side) it should be supported well no matter how little screw there is left on a certain side.

[Geezer]

It's worth a shot to try the 40mm...worst case scenario they won't be long enough. 38mm for the fan only leaves you 2mm to traverse both the case and the radiator shroud, but for all we know the 40mm screws are poorly machined and are actually 42mm. If the 40mm are long enough, great. If not, there's always slightly longer screws and a dremel.

[Church]

If there are just 1-2mm extra mm .. isn't that just the job for washer rings as spacers? Imho not worth dremeling off.

[Geezer]

If there are just 1-2mm extra mm .. isn't that just the job for washer rings as spacers? Imho not worth dremeling off.

I guess it depends on what you're going for. If you're just hoping to get it together in one piece without damaging components, anything that gets the job done is fair game. For all the talk about shrouds and gaskets and sealing the rad/fan "unit" to properly direct airflow, creating a gap with washers anywhere other than the outside of the case is iffy, and putting washers outside the case is usually ugly. Easy enough to grind 1-2mm off a screw if need be, and grinding (as opposed to cutting) is often a superior way to ensure the threads are left as undisturbed as possible.

[SlackerXL]

On the topic of the plastic card... don't think that will save you from rad puncture all the time.

the plastic card is supposed to be used for test purposes,
you use it as a measuring unit on just one fan
just to make sure the screw doesn't touch the fins/channels.
it helps you see the extra length of the screw you 'll have to deal with
you're not supposed to leave it there
you're supposed to insert the proper amount and kind of standoffs
ex fan grill, fan gasket, grommets, or something similar
so that the screw provides a secure mount without puncturing the rad


I don't remember where from, but some guy did that test and ended up puncturing his radiator anyways. Another punctured his radiator through a puncture guard :yepp:

in these cases i think the problem is usually the actual user and his methods
you don't use electric screwdrivers when mounting fans on rads.
the threads on the rads are rather short and a couple more twists will most likely destroy them.
you use a normal screwdriver and feel the resistance of the screw as it grasps the thread.
It will require quite some force to penetrate a credit/plastic card
or whatever you've put under those threads as a shield.

anyway
go with the 40mm ones and see for yourself
the M4s provide about 3 full threads on 2mm length.
that is usually enough for a safe mount.

[ScottALot]

^Sounds good, I'll be ordering once I get my second and third UK3K ...

EDIT: Actually, I may order the 45mm ... they show a picture of the 45mm working on a 38mm fan and radiator w/o going through a case, so that makes me think that it'll work wonderfully for me.