Modding Hole Saw Question

lo chaps

to cut a hole using a hole-saw..for a 120mm fan do u use a 127mm hole saw??

 

You use a 102mm holesaw. Mark the 4 screw holes for the fan and join both pairs of them together to find the centre point, then reach for your drill and holesaw

 

Do you mean 112? Because I've measured at 102mm definatly seems too small, you are wasting about 1cm around the edges of airflow!

 

I don't think 112mm ones exist...I might be wrong.

 

My dad says there are 4.5" holesaws available, which is about 114mm, he is briging me one tomorrow from work so that I can drill 3 holes into my case. Will let you know whether this works or not!

 

sory it was a typo...its a 127mm holesaw....for a 120mm fan...thats what i wanted to know?

 

127mm is bigger than the actual fan. WillyWonka has the right size, 112/ 114mm

 

go for the nearest size that is smaller then the hole you intend to cut, you will gain a extra few mm in hole size due to vibration during cutting.

 

Hi just thought you might like to know that RS have a 121mm Holesaw which should be perfect

Starett Safe Flex HSS Holesaws

 

No, it wouldn't be perfect as the hole would be bigger than the fan, leaving a gap around the edge, unsighty!

The extreme maximum you would want for a hole is 115mm. But you would want a 110mm hole really as the shape of the hole in the fan is not perfectly round.

 

Your right. I hadn't thought about that. You can always file it out if necessary anyway.

 

if you want to make 120mm hole use this :

 

as i allready have an existing 80mm hole im prob gonna mark out the size of the 120mm fan using a template then use a drill and drill holes allround then dremel thru the holes then using sanding drums clean up the hole to the perfect size...

 

That's a better idea since using a hole saw on an existing hole can prove to be difficult since you don't have the pilot guide hole (the drill bit in the middle which prevents your hole saw from sliding side to side).

BTW the way to fix that is to glue a piece of wood or even plexi to the inside of the panel and then drill your pilot hole into that.

 

I didn't use a holesaw after all, I used an electric jigsaw, it works like a charm! I just drew the lines for cutting, then jigsawed over the line.

As for the template above, I think it would look better if the hole was perfectly round. If you are concerned about airflow, the bit of fan that would be covered if the hole was round would not in fact affect airflow at all. If you look at a fan the gap in the corners between the fan casing and the blades is actually wider than at the sides. Hope this makes sense!