@Gianluca - If you're willing to publish, what is your max allowable deviation across a panel for "flatness". Is there any guidance you could provide re: what to generally expect?
The reason I ask, is that over the 6 chassis (20 separate heatsinks ... 4x4 and 2x2) I have, all of them are wonderful and are perfectly suitable for the task at hand. I love them. Admittedly, it took a few tries for me to learn to assemble them properly. However, I've never personally needed nor expected a "flat" heatsink. All my amplifiers (with the exception of the VFET amp) have the devices mounted directly onto the heatsinks, so I've never needed to mate two 'flat' surfaces together or use a sizable heat spreader. With that said, when I've put some of my sinks against a 'flat' glass table, there are noticeable gaps. I wouldn't call any of them "flat". It doesn't matter to me, but I thought I'd ask for the sake of discussion, and also for a future amp I'm considering similar to what MEPER is doing.
Sure, I am happy to answer.
Main reason these are not perfectly flat is because of how they are made. They are extruded and then smelted so it can happen the temperature make them warp.
The reason why our supplier does not give us a "tolerance range" is exactly because of this. When you work with heat there is always going to be some distortion but it is hard to calculate it exactly.
A couple of years ago when we started supplying our chassis to the DiyAudioStore I briefly talked with Jason about this. A possible solution would have been to mill some mm out of the heatsink surface to make sure they are perfectly flat and smooth.
We prefered not go to this route because it would have just increased production time and cost and most people were ok with the original "flatness" of the heatsinks or they would not mind to come up with a simple solution like the one suggested by ZM.
as shown in (somewhere up) linked my endeavor with VFet Lotery amp, and I know from experience that same applies for other Modu heatsinks - there is no need for lapping them
slight warped in longitudinal, but surface flatness showing as more than decent extrusion
as seen, I needed to correct/even T Bar surface, not Modu side
slight warped in longitudinal, but surface flatness showing as more than decent extrusion
as seen, I needed to correct/even T Bar surface, not Modu side
^ 
@Gianluca - thanks so much for taking the time to answer. Greatly appreciated. Once again, in case I didn't state it clearly enough, I love the sinks your company provides. That's why I have so many of them and likely will 'need' at least 8 more.. I'm also aware of why they're they way they are. I was simply curious if you had a spec / tolerance available.
Back to our regularly scheduled programming.
With thanks and kind regards.
@Gianluca - thanks so much for taking the time to answer. Greatly appreciated. Once again, in case I didn't state it clearly enough, I love the sinks your company provides. That's why I have so many of them and likely will 'need' at least 8 more.
. I'm also aware of why they're they way they are. I was simply curious if you had a spec / tolerance available. Back to our regularly scheduled programming.
With thanks and kind regards.
The Modushop heatsinks are certainly flat enough for all but the most demanding applications.
They worked well with the original Diy VFET chassis and the T-bracket extrusions that were included with the kit. If one is more demanding, then it is very straightforward to wrap a piece of 400 grit wet sandpaper around an extrusion (or whatever object needs to have a flat surface) and apply to knock down the high spots.
They worked well with the original Diy VFET chassis and the T-bracket extrusions that were included with the kit. If one is more demanding, then it is very straightforward to wrap a piece of 400 grit wet sandpaper around an extrusion (or whatever object needs to have a flat surface) and apply to knock down the high spots.
As always thank you all for your kind words, they are much appreciated It's always nice to see our hard job gets rewarded.
@MEPER I'll get back to you regarding the plates on Wednesday (we are closed on Monday and Tuesday due to a national holiday) as soon as I am in my office
It's always nice to see our hard job gets rewarded.@MEPER I'll get back to you regarding the plates on Wednesday (we are closed on Monday and Tuesday due to a national holiday) as soon as I am in my office
