Buying a large hole saw

I'm going to need to buy a large holesaw to make 120mm holes in the top of my case. The bimetal hole saws at home depot at 4.5" (what i was told is the size to cut for 120mm fans) are about $27. Well, in all reality I'm only going to be making two holes with this saw so $27 seems like a bit much. Do you guys know where I can find a cheaper one, or better yet a used one? I've been looking around but can't find one. Also, don't some stores have tool rental programs? Not sure that applies to a holesaw but just wanted to ask in case. Thanks!

Oh, and I put this in the watercooling section naturally because I'm cutting the holes in my case for my heatercore fans. If this thread goes better somewhere else, mods, feel free to move it.

ebay is a good place for some cheap generic tools that aren't the best, but will do the trick for two holes.

I need a bimetal hole saw to cut through aluminum correct? Or since the aluminum on the lian li is pretty thin would any hole saw work? Checking on ebay again...

Get a bimetal. I don't think a wood hole saw would get you anywhere. Check out www.harborfreight.com. They have cheap tools. If there is a retail store in your area you can go there and not have to pay shipping. If you have any friend's or relatives that have a lot of tools call them up. Borrowing is the best. Make sure you have a good drill. Also pick up some cutting oil. You'll thank yourself.

Definetely go Bi-Metal, they can cut steel and aluminum without too much wear, and are good for quite a few cuts. I managed to get my 4.5" Bi-metal Hole-Saw from an online vendor for $18, including the Mandrel, and it did a fine job on my steel case.

If you buy your Hole saw, avoid ones with a "built-in" Mandrel (the bit in the center); they are invariably of lower quality.

Your best bet of course is to find someone who has the tools already, and is willing to give you some time on them. I used my school's shop room for the work I did on my case, and it made the work a lot easier (and ultimately more professional looking), having a very-experienced shop-teacher watching over my shoulder the whole time.

You also want to use a drill press when using a hole saw to make cuts in your case. A 4.5" Hole Saw and a hand drill is a great combination for mistakes or accidents - a drill-press is easier, safer, and much more accurate.

I would also suggest that you dissassemble your case before doing any work, it's *much* easier that way, and it'll speed up the work too .

Don't forget your safety goggles

How can i take off the top of my lian-li pc-75 case? I have the drill press so that would work but I don't know how to take the top part of the case off...

Most cases have the panels and pieces riveted together; you can very carefully drill the rivets out with a very thin drill-bit in order to remove them, and then use either a rivet gun (more rivets - semi-permanent and very solid), or screws to hold everything together after you're done your work

With my case, a Chieftec Dragon Full-Tower, I used screws to put it back together afterwards, so it's easier to take apart again later should I have a need.

Don't use a hole saw. The metal your case is made of is thin and flimsy and with a hole saw that big when it grabs it is going to twist like hell and buckle whatever you are cutting. Also your center drill is trying to hold a 4" + bit center when all it has to holding the bit in place is a few thousanths steel or aluminum. You can very easily end up with a hole a lot larger then you want.

sure you may get lucky if you drill it on a drill press where you can ensure you hole is being cut evenly all the way around. with the metal clamped to a piece of wood which is clamped to the drill base. That is if it doesn't grab and rip it off the fixture and slam it into the support post.

I use a compass to layout the hole, a jig saw to cut out most of the meat. Some nibblers to get it close. and a dremel or file to finish it off. The holes are always the right size and most of all perfectly round. and I did it without having to tear the whole case apart.

You only get one shot at doing this right. If you rush into it and screw up your case doing it you are going to be one very unhappy camper.

Electron Chaser said:

Don't use a hole saw. The metal your case is made of is thin and flimsy and with a hole saw that big when it grabs it is going to twist like hell and buckle whatever you are cutting. Also your center drill is trying to hold a 4" + bit center when all it has to holding the bit in place is a few thousanths steel or aluminum. You can very easily end up with a hole a lot larger then you want...

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Actually, often metal is *a lot* thicker than a few thousanths, usually its actually more like a few hundreths. 18 gauge metal is very common, and is 0.0478" thick. Aluminum can be even thicker. Anyways, you do have a point though, if you arent careful you can easily buckle the metal. Put a piece of wood under it for sure to prevent and movement.

If you want a nice hole, I wouldn't recommend that you use a Dremel or a jig saw, it is very difficult to get a perfect hole that way. It is much easier and faster to just use a hole saw, just don't rush.

Oh and yeah, definitely get a bimetal hole saw.

Alternative Modding section might have been better but I guess people do have experience with HC cutting.

I used a 4.5" bimetal hole saw with a Black and Decker drill. Boy, I wished I had a drill press. The torque of the drill will invariably make your hand move resulting in some scratches outside the "cutting area". Right now, I'm sanding it and painting it so it should be alright if you are going to go that route.

I used a home depot holesaw to cut some holes for 80mm fans. You need a really really powerful drill...the kind that will twist your arm into a knot when the bit jams. And you need to secure the case well, otherwise you'll spin it around and probably bang yourself.

When I needed a hole for a 120mm fan I decide to use my jigsaw and Dremel. I laid out a square hole (with diagonal cuts at the corners for mounting holes) and I used the Dremel cut-off wheel to plunge into the panel to start a cut, then I'd slip in the jigsaw to finish the cut. I make a square hole that worked great. The diagonal cuts at the corners were simply cut with the Dremel.

Since I had the Dremel and jigsaw it just worked out better for me. All I needed to buy was a metal-cutting blade for the jigsaw. I think this method was much safer.

if you dont want scratches... cut from the inside of the case. that way you wont see them if you make any.

If you have access to a drill press, You can use a piece of 1x8 under the top piece and some small pieces of 1x8 or 1x6 to clamp it down. You should have no problems at long as you drill slowly and use some lubricant. WD40 is a good lubricant and it cleans off easily. Spray it on as you start and give it a spray often during cutting. If you see smoke you're drilling to fast or not using enough lubricant. Dill a small pilot hole(3/16) in the exact center and us that to line your piece up under the hole saw. Then clamp everything down using the 1x8 underneath and smaller piece under the clamps. I've had better success drilling from the inside to the outside. I've drilled hole in some really cheap cases using this method.

icypyro said:

Actually, often metal is *a lot* thicker than a few thousanths, usually its actually more like a few hundreths. 18 gauge metal is very common, and is 0.0478" thick. Aluminum can be even thicker. Anyways, you do have a point though, if you arent careful you can easily buckle the metal. Put a piece of wood under it for sure to prevent and movement.

If you want a nice hole, I wouldn't recommend that you use a Dremel or a jig saw, it is very difficult to get a perfect hole that way. It is much easier and faster to just use a hole saw, just don't rush.

Oh and yeah, definitely get a bimetal hole saw.

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You don't cut the entire hole out with the jug saw you just get close to your line. the rest you do by hand with a nibbler and a dremel you can bring it right to the line and always make sure that it is perfect. I have built over a hundred automated projects. I work with machinists and tool makers everyday to do my job. If you want fast easy and risky go the hole saw route. ( Lastly .0478 is always pronounced 48 thousanths or 47 and 8 tenths if you wanna get technical. If you said a few hundreths to a toolmaker he would think you mean a few hundred thousanths or roughly a quarter inch. The term hundreths is never used in that fashion just an FYI not a flame)

And 48 is a few thousanths, just how thick is 48 thousanths. roughly the width of 16 human hairs. or an aluminum can folded folded twice. Not a lot of metal there to support a whole saw that size and expect the rest of the case to not suffer some sort of damage. Steel will definately survive it better then aluminium though. Can it be done? Sure! I'm not saying it can't I have done it myself when pressed for time and spending someone elses dime. However if your not used to using a hole saw, not extremely careful or used to the tremendous torque they can generate you can ruin your case or more importantly hurt yourself badly especially if your work decides to spin in the drill press.

One last thing we have an expression in my business.

"Good, Fast, and Cheap . Pick two"

I tried making 120mm holes using a bi-metal too. I did it by hand without a drill press. I regret it. I found a way to hide the ugly it created, but just by luck.

My recommended approach:

Cover the workpiece area with masking tape. In fact, use the aluminum HVAC type tape since it is pretty tough stuff. This will prevent scratches in the area you want to preserve the finish. If you care about the finish on the inside of the case, put tape on that side too.

For a 120mm, use a CD disk as a template to draw a circle on your workpiece. They are 120mm in diameter. Use a jigsaw with a high tooth count to cut close to the line, then a Dremel to finish the job. If the Dremel hops up it will hit the tape and not the paint you want to preserve. You can "sneak up" on your perfect 120mm circle using the Dremel.

For practice, try making a smaller hole first. See how close you can get to the line with the jig saw without causing buckling or deformation of the metal outside of the line. Apply what you've learned to your final hole. You could situate your practice smaller hole in the middle of the final 120mm hole if you want.

All of the supplies needed can be purchased at Home Depot or Lowes.

I did a little research and found an idea that might help cutting holes without a drill press. Now, the problem with the drill press is that in order to use it I believe I'd have to take the top of the case off, which looks like it'd be really hard. So let's say I use a high-powered drill with the 4.5" holesaw. People say the bad part about this is keeping it steady and scratching. What I read on the other site that i could do is this...

What I could do is take a 2x4 and cut the two 120mm holes in that. Then clamp the 2x4 to the top of the case and use those holes as guides. I read this on anandtech. You guys think that'd be a good idea? sounds like it to me...

For practice, try making a smaller hole first. See how close you can get to the line with the jig saw without causing buckling or deformation of the metal outside of the line. Apply what you've learned to your final hole. You could situate your practice smaller hole in the middle of the final 120mm hole if you want.

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I don't think you can do with the metal cutting hole saws from home depot...those saws are guided by a drill bit through the mandrel.

Do you have some other mandrel in mind?

What I could do is take a 2x4 and cut the two 120mm holes in that. Then clamp the 2x4 to the top of the case and use those holes as guides. I read this on anandtech. You guys think that'd be a good idea? sounds like it to me...

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A 2x4 is only 3 1/2" wide...how do you make a 4 1/2" hole in that?? Or am I missing something?

mribnik, that would be a definite improvement. The only problem I see is getting the two pieces of 2 X 4 lined up perfectly. Instead, perhaps using a solid piece of 2 X 4 (in other words, without the hole) on the bottom and the piece of 2 X 4 with the 120mm pre-drilled hole on the top.

Sand the two pieces of wood to a smooth finish otherwise the clamping pressure will cause dents/scratches.

Also, to keep the two pieces of wood from slipping out of position during sawing, cover both of them with double-stick tape (thinnest you can find).

Now that I think about it, there would be no need to pre-drill the 120mm hole in the top piece of wood. All you'd need to do is drill the arbor hole through all three layers.

Be sure that the hole saw can accommodate the total thickness of the top layer of wood and the metal, otherwise you'll run out of available cutting depth.

Graystar,

Read my post more carefully. I do not suggest drilling a smaller hole with a smaller hole saw. I suggest using a jig saw and dremel to make a smaller hole as a practice hole, leaving plenty of material outside of the practice hole for the final 120mm hole.

Ok, well it doesn't need to be a 2x4, just a slab of wood to put on top.

Ok moregooder, let me see if I understand you. You are basically saying to stick a slab of wood on the top of the case, and a slab of wood under the top of the case. Then sand them both down so they can clamp down. Then I draw the 120mm circles with a dot in the center and drill the arbor all the way through all three layers (the purpose of this being that I'd have a center hole cut into the metal so the drill will be even more steady?). Then I would go back and drill the hole through?