Multi-Hole Drilled Water Block – Part of the Continuing Saga of the ‘Shade Tree’ Machinist

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Good DIY – Owen Stevens

As you may have read in my past articles, I like to drill and “machine” my own water blocks. From time to time I will either have an idea for a new block or I’ll come across someone else’s idea that I would like to try. Well, this time when I got the itch to “make something” (no it wasn’t an urge to make a mess in the garage as my wife might say).

I remembered an idea I saw at Superior Cooling Methodologies. The person there made an interesting multi-hole water block that combined increased surface area and internal block water volume. So what could I do but promptly order some ½” copper bar stock!

Here is the bar stock I used, a piece of left over ¼” I had lying around the garage (yeah I have bar stock lying around in my garage – isn’t life tough) and my newly arrives ½” x 1′ piece.


Top and side view.

I quickly marked off a 3-1/4″ long piece and got out my circular saw with a metal cutting blade out to cut them off.


This sucker is loud and messy but it cuts copper like a hot knife though butter. OK – maybe it’s more like a butter knife through an overcooked steak but hey, it’s easier than a hacksaw!


Oh yeah and don’t forget the safety gear – ear plugs, safety glasses, dust mask, and heavy leather gloves. I think the saw “melts” away the copper more than cuts it. Trust me – you don’t want any of it on your skin or in your eyes – Ouch!


Stick it in the Workmate bench and go to town!


I usually make a little knick to start with to make sure I have the depth right and the measurement close. Note: today I am cutting the ¼” copper and ½” copper together to save time.


The ½” piece right on the mark, well pretty close. Did I say it wasn’t a precision process!


It doesn’t cut smooth but I’ve got a belt/disc sander that with fix that!

Bar 1

Here’s the ¼” piece in the same state. Yeah, yeah, measure twice cut once blah, blah, blah.



Owen Stevens

Next I attached my template – isn’t graph paper grand! It can be a poor man’s AutoCAD! OK, and a lazy man’s too, which I admit I am sometimes. (Note to self: Don’t mention the fact that this is the long piece of ½” copper because I screwed up the first one – doh!)


And then center punch the drill locations.


Purdy lil’ dimples aren’t they? OK – I don’t get out much!


Now to my new floor model drill press! (Note to self: Don’t mention that I smoked the motor on the green bench top drill press below with a different attempt.)


Start a drillin’!


All done drillin’! This new 16 speed floor model drill press really kicks! And it only cost me $165! (Note to self: Don’t tell them that wife accused me of “killing” other drill press as an excuse to get this one. And stop putting notes to myself!)

I know what you are thinking: “How does the water flow through that?!” Now here is the “trade secret” I got from the generous and gracious persons at Superior Cooling Methodologies: You cut the metal out between the holes! Now why didn’t I think of that?!

Air Tool

My trusty air powered hearing loss generator, er, I mean die grinder.



Owen Stevens

Any way it’s not really the grinder that’s loud – it’s my air compressor! It’s the red cylinder hiding back there in the corner; a good shot of my “shop” too!


So here is a start at the cutting procedure.


Man! Copper sure eats up those fiber reinforced cutting wheels! Original one the left, one of the many used on the right. I found that the non-reinforced ones work better because they are thinner, but they can shatter if you’re not careful. Reminder: Always wear safety glasses and gear!


All done with the cutting and a quick surfacing on the belt sander. I love this bet sander it takes all the work out of cleaning up my sloppy “machining”!


Next I used the same template to mark the top ¼” piece. Here’s the resulting dimples I drilled to make the top similar to the bottom.

Line Up

See they do kinda’ line up!

Next I made some ‘home made’ ½” inch hose barbs. I got this idea when I saw that Home Depot didn’t have any ½” barb by ¼” pipe thread fittings.


The nice part is that the parts for two only cost $1.25!

You start by sawing a ½” hose barb in half. You get a two for one here! Note: These are for pex-type pipe so size wise they are closer to ¾” in outer diameter.


Then I cut in the threads with my ¼” pipe tape. Here is a trick for the threading: When I bought the ¼” pipe tape, it came with a drill bit that was sized for the hole the tap needs. I used the drill bit to enlarge the hole, otherwise the tap expands the ½” fitting too much and the plastic cracks. Not that I cracked ant fitting myself – OK about four! But at $0.35 a piece, the ½” couplings are pretty expendable.



Owen Stevens

Then I threaded in some galvanized ¼” threaded couplings with thread tape. They were out of brass ones at Home Depot but the galvanized pieces were only $0.40, so I thought “Why not?” Of course, they may rust out eventually – being steel – but before then, I’ll have a new block (knowing me)!

Top 1

The fittings need a hole so I drilled two the the top.

Top 2

I noticed that the “pins” from the bottom might not work with the fittings if they go in too far…


so I milled out the area of the inlet and outlet. I did this because on another block I didn’t, and when I tightened the fittings, they actually pushed the block apart from contact with the sides of the channel.


I was right about the clearance from this “dry fit” of the pieces.


I clamped it up and soldered it together with some high silver content solder. Damn! That silver based solder takes forever to melt! I think next time I’ll use an oxyacetylene torch! If I get a bonus from work, I’m going to make a trip to the tool store. Do you think my wife will buy the torch as a better way to light the barbecue?!


Well here is the top of the final assembly. I ended up putting clear epoxy around the fittings because in my “bubble test” one leaked. My “bubble test” is just to plug one fitting and then blow air into the other with the block submerged in a bowl of water. Any bubbles and that’s a potential leak.


A bottom view with my so-so lapping job. I am a little too impatient to lap this to a mirror finish – maybe next time. I countersunk the mounting holes to support my four bolt mounting method.

Here is a rough sketch of the way I mount the CPU with a force of 20+ lbs each time:


Yes, I use four bolts – the sketch is just of one. To install it, I thread the screw into the standoff and then tighten the nut to get a little extra force. I originally had the screw the exact length to get 20 lbs, but when I went to a thicker block (it’s ¾” now, remember!) I had to make some adjustments, so I added the top nuts. I use Arctic Silver III thermal compound.


I put it in and it worked very well! The two lines coming out are from another test and were shortened, plugged, and tucked into the case when I was done. Flow is from pump to block to rad to pump. My system uses ½” fiber reinforced PVC tubing for all but the test lines off the two tees, they’re clear PVC.

I have a PondMaster 250 gph Pump. The water is cooled by a 1991 Ford Escort heater core that is in turn cooled by four 80mm Panaflo L series fans “pulling” air from outside the case through the rad. There are another another four 80mm Panaflo L series exhaust fans at the back of the case above my PSU, which is a “whisper quiet” Enermax 431W unit.

How does it perform you might ask? Excellent!

I have a hard time getting my slightly overclocked XP 1600+ (1.78V, 10.5 x 140 MHz = 1470 MHz) to go even 5C above ambient temps! Running at this speed, I calculate C/W to be ~0.074!

To get a C/W, I first burned it in for two days, then I measured a CPU temp under 100% load for two hours of 26 C (read via XP internal diode – thanks Hoot!), a 21 C room temp read via a digital indoor outdoor thermometer (my CPU loves my cold basement!), and from Watts Calculator II, I get 68W for the CPU power (1.78V w/ 5% overclock).

What do I say? Success!

I hope you enjoyed my latest endevour of making Multi-Hole Drilled Water Block. It was a lot of fun and this block works great for me.

Owen Stevens


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