Cathar Clone
 

Cathar was good enought to grant me permission to make a clone of his block, with a few minor differences...

first, I'll be using 1/16 inch channels and 1/16 inch fins as opposed to 1 mm channels and 1 mm fins

I won't be making as cool of a jet-impingent block as he did, but alas it will be similar

and I've also added a center bar , as shown below to hopefuully invrease surface area and turbulence.

So now the questions:

What do you think of this block design?
Do you think I should either lower the centerbar, eleminate it completly, or make 2 smaller ones (like protruding a 32nd above the base) to increase turbulence, or what?


btw, I'm making this on a bridgeport mill with the 1/16 bit (hopefully I don't break them all!)

here's the base:

Heres the top. fairly inconsequental, but does show my intentions. the channel does span the entirety of the fins

How high are the channels? 1/16?

I like the idea of lowering the center bar slightly, maybe half as high as the fins are?

You can do something even better: use round saw blades to cut the channels, and leave a peak in the center, to help channel the coolant. (see info on blades in Radius thread)

the fins are 3/16 inchs high, and the whole base is a quater inch thick

I'm thinking I'll just machine that center channel to 3/16 high.

How about taking a ball endmill and make the ends of the channels on each side of the center bar pointed at the top where the channels meet the center bar and just leave the bar at the same level as the rest of the fins

Looks good so far.

I really don't want to comment because I'm interested to see the results.

I already simulated most of what's being proposed here, but never built it yet, and am keen to not provide any influence that might sway too far away from some fresh ideas.

One point though - your channel walls should be 4-5x as high as they are wide. Getting much below 4x doesn't give enough chance for the heat to migrate to the water. 3x as high is pretty low - not excessively so - but if you can bring that up a bit it will perform better. Higher than 5x tends to be unneeded.

However, 1/16" end-mills don't tend to be much longer than 3/16", so you may have to stick with 3x anyway...

Update: my bits will go down to 1/4 inches deep, so I'll stick with my original plan
thanx all

In my experience, a 1:1 wall/channel ratio works best when getting down to these sorts of measurements. I did try 0.75mm fins with 1mm channels and saw a (small) performance loss. Going with 3/64 fins with 1/16th channels is the same ratio (just slightly bigger). However, because it is larger, it may still work fine and my findings may have been specific to 0.75:1 mm, and not be applicable to 3/64:1/16. One way to find out....

well, I think I'll stick to the original plan, having 1/4 inch deep channes, 1/16 wide... with the center bar all the way to the top. If for some reason it causes a problem, I can always trim it down a bit

Nick C......let us know how it comes out.

Looking good

always remember what way the tool turns

how ya gonna mill that square channel on the top plate?

maybe it has 'actual' radii in it that he just didn't put in the CAD model?

right, that middle bar was a quick addition to the block, I didn't bother putting the radii in it.

btw the radius will be 1/32

actually i think unloaded was referring to the rectangular pocket in the top plate (the one that the center hole passes through). but you probably just didnt' put the radii in there either. why bother? too much wasted time.

kinda bad news...

the power-feed on the mill desided to stick on, and then took out the middle bar on the 2nd pass on the first fin.

so I disengaed work, and ran the powerfeed for like 10 mins insureing it wouldnt stick on again

well, it did it again on the 2nd fin, 4th fin, 5th, and 7th.

so I totally had to remove it

makes me mad, after it would stick I'd test it for a long time and it wouldn't do it...

hasn't done it since I was done either

Eh, you didn't need that middle bar anyways...;)

lol

well, I finished it, and the silicone is drying... I desided to make the flow director into another seperate pice of plexi


btw, mahicng CU in 1/16 bits size isn't HARD, but can be tedious...
pics tommorrow

Albigger where yu live at in ohio i live in barberton norton area.

Hey, got the pics


anyway, here are the pics:
The Clone!

the base thickness is 5/16 overall, with 1/16 seperating the core from the fins. the whole thing is 13/16 inches thick.

the plexy in the middle is a flow director and is nearly identicle to Cathars.


I have no commercial blocks to compare it to (made all my own ;)), and and halfway through leek testing. gotta get a Y and some 3/8 tubing before I can complete testing and install it. I'll tell ya all how it perforums when/if I get the parts soon

-Nick C

Looks very good for a hand milled block.

correct me if i'm wrong, but i'm still reading about cathars project. his project is based on massive water flow. if you had a situtation that the flow was not as high you would be better off with a different design correct?

Nick C:

Nice looking block....is that an old BridgePort mill you are using?

I like the plexi-in-the-middle-thing. Looks awesome! Great work!