I've been a very happy owner of a Monolith Flat for about a year and a half. Ecstatic, really. But a question has been nagging at me for months:

When I bought the grinder, I recall seeing posts to the effect that the Flat's architecture ensures alignment of the burrs. I think this was attributed to the dead-simple design and exacting manufacturing tolerances. Further, the manual gives instructions for replacing the burrs, but doesn't provide any information about aligning the burrs after doing so. The implication is that it's not necessary. Is this true?

If so, is it the design, tolerances or both? If not, what's involved in burr alignment? Shims? (I'm not about to remove my burrs to find out!)

Seems to me the manufacturing tolerances of the burrs would have something to do with it -- e.g., relative symmetry of the discs, placement and tolerance of the screw holes, and maybe even the cutting pattern. Isn't some compensation for this required?

Has anyone got information about burr alignment on the Flat? Has anyone done the marker test on their Flat's burrs to check the alignment?

I'm not saying I think my Flat has any alignment issues, or any issues at all for that matter, but I'm curious.

Funny you should ask! I've wondered the same since it arrived but have never bothered to check. Maybe we should both do the marker test today?

Ira

ira wrote:Funny you should ask! I've wondered the same since it arrived but have never bothered to check. Maybe we should both do the marker test today?

Marker-test...

Well, I just tried but I'm uncertain of the results. with the lock loose the burrs start touching but tightening the lock makes them stop. That happens for almost one whole number. Looking at the burrs after that, the bottom one seems to have been touched at the very outer edge 80% of the way around and the top one was touched at 3 places about equally spaced around the burr. Two of those are clearly burrs left from grinding Closer examination seems to indicate that to top one still has a few burrs that might be what is touching, almost as if the burrs are not fully broken in. A minute with a calculator seems to indicate it's probably only had around 35 pounds of coffee through it in the time I've owned it. Here are some pictures of the outer edge of the top burr.

My Flat is about 16 months old and these are Mythos burrs or they at least the word Mythos is clearly stamped on the side of the top burr.

The marks are pretty evenly spaced around the burr and the 2 even looking marks are about opposite each other.

So what does the marker test show

That some people are anal retentive and/or have nothing better to do with their time, lmao.

As someone who is A. a satisfied Monolith owner and B. one who has tried with varying success in aligning burrs it can be tricky. It's funny to me this thread is up. I just spent this morning re-aligning SSP burrs on My Super Jolly. I used the marker method before and got it about as close as I could. Just yesterday I took it to work to a customer with a machine shop and checked it with some precision instruments. With the bottom rotating burr installed I found it was out .001" from the high point to the low point unshimmed. I was actually impressed how good this was coming from Mazzer, in a 15 year old grinder. The top burr was .002 out after spending 2 hrs shimming and doing the marker thing and then concluding I couldn't do any better. This morning I installed a .001 shim on the bottom and .002 on the top and it still rubs in a spot. I'll take it back tomorrow and see where its off again. If it's any better than it was then I'll probably just leave it. Its already approaching being a high end grinder. The excuse of this long winded story of my Super Jolly is to show that even if the manufacturing of the Flats is very precise, unless a considerable amount of time is spent shimming the burrs they will never be perfectly parallel. That would add considerable cost to an already expensive, very high quality grinder. I would think you start approaching the law of diminishing returns.
The description for the Flat on its website claims "Precisely aligned". That gives a little wiggle room. it doesn't say parallel. Even if shafts and bearings are machined to be exactly parallel or perpendicular, Kafatek is still subject to the manufacturing tolerances of mass produced burrs. The SSP burrs I received appear to be very high quality and likely very true. I suspect the SSP burrs would be even better.

Just FYI the current or more recent batch of Flats does not use Mythos burr anymore, it shares some basic dimension but Denis stated that his burr is much higher quality.
Looking at the marker test I would not be surprised if he measured each individual burr or do final alignment check before shipping the grinder.

So for example, when the SSP burrs go up for sale, how does one align them after installing them? The marker tests explanations are helpful, but what is the process for alignment?