Update:
I got the collar unstuck, was due to safety button getting stuck.
My grinds are too coarse for espresso even when in finest settings, I comment on that at bottom, thanks for help though.
Summary:
Last summer I bought this grinder as a "buyer's remorse" item from Chris Coffee.
The savings were substantial and I figured I had an excuse to get more gear (use it to grind drip/french press for my friends from my 5lb bean orders).

While dialing it in, it jammed. I knew what I was doing, I read the directions, and I have had a Compak K10 for 4 years now.

Although I know grinders, I find them very intimidating to take apart, and so says the guy who replaced every valve on his Izzo Alex Mk1. I am tempted to send it back to chris for repair, but will give it a shot.
Or if someone in MD area looking an excellent deal, PM me.

Below is an email exchange I had with the infamous and awesome Jason Verini of Chris Coffee tech.
I am just going to paste it as I wrote it the night it happened and his reply is in direct response

George wrote:Jason,
So I get the grinder, following the instructions, I turn the motor on, and get a feel for the grind adjuster, I adjust it tighter, than looser, than stop at the number you all say is great for espresso, then I went three clicks coarser for french press.

When I went to grind that first setting, it came out super coarse, so with the grinder on I went over 2 clicks finer (with grinder on) and i felt a huge amount of resistance as I approached the -2 from where I was at (I thought to myself, "theres no way I hit the zero point")
I let it grind out the rest of the beans, and with the hopper empty and motor running (and blades turning) I try again bean free (without stress of catching spraying out thick grinds) I tried again to adjust more fine but it won't give.

Then thinking it was stuck or jammed, I tried to go more coarse, and almost zero movement. And thats where I am at, it appears it won't move, I cant remember what number its left at, but I can let you know once I get home.

If this grind adjustment got jammed at the perfect spot for french press, I wouldn't mind, but it's not, imagine the coarsest settings on a nice grinder and thats what it is producing.

I think the safety button mechanism for the grind adjustment is PITA too, clever for when moving grinder, but thats about it.

Jason wrote:George,
Sorry to hear you are having a problem with your new grinder. It's very rare to have any problems with the Macaps so hopefully it is something easy to get you working again. First off I would make sure the hopper screw is not getting stuck. Underneath the black collar there is a screw that goes in sideways, I would try removing that. I would also make sure the grind adjust button is not getting stuck on the bottom of the plastic collar. You can remove the 3 screws on top to take the collar off to see if that helps. Since you are at a coarse setting we know the burrs are not locked together. The only other thing I can think of is since you were at such a coarse setting the burrs would be real far apart and then some grinds could have gotten into the threads so when you went finer it locked up. If that's the case then the only way to free it up is to "muscle" it open again and then unscrew the upper carrier to clean out the coffee grounds. If it won't free up try jiggling the upper carrier back and forth rapidly and it should help clean some of the grinds out of the threads to get it moving again. Let me know how you make out.

I don't want to be an ass, but have you tried spraying a bit of wd40 in the threads? To prevent making a mess of your grinder, spray some in a shot glass and use a toothpick to deposit drops of wd40 on the threads.

Go ahead and be an ass, I am incompetetant when it comes to some mechanical things.
And I still am, I have never had to take apart my grinders, and the more I read its easy to screw up.

I believe here I do not to remove the burrs, which are problematic, so this is just removing the collar and applying lubricant to the threads. I understand a blow dryer or heat gun can also be effective.

I found this in another post Cleaning the burrs of a Macap M4 Stepless Grinder

I figure I got to do what is in step 2, but what do I do, do I apply lube or heat the locked threads where the two assemblies meet and twist till they are loose?

Is it possible that when dialing it in and going coarse, that I took it off the threads, and when trying to tighten it I cross threaded the assemblies?
Like I noted at the time, I adjusted it to 3 numbers less than their espresso point, the grinds were so coarse, they were cartoonish, it didnt make sense.

If you have a side facing photo of an exposed grinder that would help.

Thanks

GeorgeP922 wrote:....so this is just removing the collar and applying lubricant to the threads...do I apply lube or heat the locked threads where the two assemblies meet and twist till they are loose?

Yes, apply lube where you see the threads engaging at the base of the visible portion of the collar. At a minimum, WD40, though for extreme situations, usually automotive, many swear by PBlaster. Heat would be most effective before the solvents have a chance to evaporate from the product, so I would gently preheat (hairdryer?), then apply the penetrant and leave the grinder in a warm place. Then WAIT overnight before applying torque in the coarse (clockwise) direction; if it's still very resistant, squirt on some more and wait another day and try again. If it tightens as you go, turn it in reverse until resistance is felt, then advance again; sometimes repeated "rocking" back and forth like this will reduce resistance and minimize thread damage.

GeorgeP922 wrote:Is it possible that when dialing it in and going coarse, that I took it off the threads, and when trying to tighten it I cross threaded the assemblies?

According to your narrative, in which you only moved the dial (ring) by a couple of numbers, no way. If your ring is numbered 1..9, each number corresponds to 40 degrees, and there are many, many fine threads (at one full turn each) engaged between collar and body when it's adjusted in working range.

I don't know if there's anything significant in its history since you got it "last summer." You don't mention anything, but I have to wonder what's up if it wasn't right when you got it, but you're only dealing with it now. In any case, a "buyer's remorse" item has been through at least one other unknown person's hands, so I would be wary of possible hidden damage, though with an M4 that seems pretty unlikely. Please, this in no way should be taken as an insinuation against the competence, diligence, honesty or professionalism of Chris Coffee. I have bought "buyer's remorse" items from them and would again, and there aren't many other sellers about whom I can say that.

Thanks David.

I find the mulitple turns to be foreign, with my Compak, it feels like 180 degrees is coarsest to finest, at least for brewable espresso. Now that I have seen pictures of the threads, I can see how many thread lines there are. Most people would pull their hair out for what I will say, but my Compak K10 is so nice I NEVER have to adjust on a blend. I freeze and only put in hopper three days worth, after three days the blend degasses enough where the shots run and are 2 oz. I work my system so I dont have to adjust and I like it fine. Worth every dollar the K10.

As far as not using it for a year, well I just bought and moved into my first house when I ordered. Being a compulsive gear collector, and always wanting to give my mom a good grinder for her french press I ordered(she gets her coffee through me, espresso blends are her favorite, so except for sneaking it into the grocery store, no good grind is available).

Now after this jammed, and Jason wrote me the email I procrastinated (had lots of important stuff), then I realized I wasnt gonna do anything, so I hid it in my bathroom closet.

Then on Paradise Roasters, they started selling the Yama siphon brewer and I remembered I had bought a drip dedicated doserless grinder and needed it, for the one time I would brew siphon

So, I found this video:
I am going to do the whole burr assembly, (assuming I get it off) and see if the previous customer jammed a pound of beans in there. I would suppose I should clean my Compak too, never cleaned in 4.5 years (5lb a week). The doser is still good as new (vacuume it from time to time).

Thanks for the tips! If it is dirty, or I see gunk in the threads, I will shoot some photos.

Update:
So I go and pull this thing out of my bathroom closet to show a friend.
Immediately the adjuster moves left and right. I will chalk it up to the "safety button" needed to be depressed before adjusting.

Now, I am not done yet with this grinder.
The grinds seem very coarse, with not much variance between fine drip grind produced and burrs hitting each other.

So I adjusted the grinder till the burrs touched, must note that it got louder as you approached the zero point, Im sure this is normal(air noise), just strange to me, my Compak K10 is rather quiet all around or maybe conical are quieter.
When they touched, I adjusted a few hairs coarser and added beans (with motor running).
No beans made it through That cant be normal could it?
It seems that there was a gap between zero and when beans could pass, lets say this was 1-2cm turn on the adjuster allowed beans to pass.

I ground quite a bit of what I thought was a setting that would net fine ground coffee suitable for espresso.
What I got was something great for drip.

Could it be my burrs are not alligned? Could I just be spoiled by the Conical Compak K10?

FWIW this suits my purposes, its a birthday gift for my french press enjoying mother.

However I am disheartened it appears that it will not grind brewable espresso grinds incase one day I want to use it.

My guess for action would be, take it apart, inspect and clean the burrs, take photos and post.
I will also experiment with more beans, hitting zero while grinding and trying to achieve its fineset grind.

Adjusted properly the M4 will grind for espresso but would make a lousy french press grinder IMO. Flat burr grinders do make much more noise when zeroing then a conical. How far did you turn the adjuster to get from "no beans coming through to drip"?

Lousy French Press grinder? I will admit, when you get to the coarser side, its more like shredding/mulching beans instead of grinding them (shards too big to brew), so I could see not a lot of variance for a drip loving person who does french, pourover and siphon.
I figured as a drip grinder, it beat out the baratza and other 100$ plastic grinders, or sneaking it into grocery store in shame . For the same purpose I considered the Rocky, till this buyers remorse item was available for the same price. (if there is something better for less, I would be willing to sell this to an espresso enthusiast at a loss).

Thanks for the info on the noise with flat burrs as they get closer. I skipped zeroing my baby Compak K10 so this was my first time.
I am still curious about the "no grind zone" from zero to when beans are crushed. Im guessing thats normal with flat burr.

Now how far was I when the grind got to drip, not very far from zero.
When sorting this out, I had half a pound to throw at this test (plus only a lb left in freezer for spro). When I get more beans I will let you know. I will be able to do this all over again to confirm repeated results.

But as far as I remember it felt as if I was on the finest setting after zero.
The coffee produced felt like sand/salt vs my compak that made grounds feel like flour.

I also must say, that I still don't get the "lots and lots of turn on stepless" crowd. I feel that maybe 3 full 360 turns is the range from lawn mulcher to zero point.

Thanks again, I will update with more tests and pictures.

GeorgeP922 wrote:I find the mulitple turns to be foreign, with my Compak, it feels like 180 degrees is coarsest to finest, at least for brewable espresso.

Not to belabor this, which may be obvious by now, but "multiple turns," in fact many turns, are needed to completely remove the collar from the body, NOT to effect adjustments within any reasonable working range. In that sense, it's just like the K10, only the grind changes faster than with the K10, for sure. I've never ground for anything coarser than espresso on either the K10 or M4, but on the M4 the full range of espresso settings I use ranges over an interval of about 1.0-1.3 cm movement measured at the outer diameter of the black plastic ring with the index numbers on it. The K10's adjustment is less sensitive, so its working interval will be quite a bit larger.

I saw no indication that you have actually got the collar out and cleaned! I would do that ASAP, since lack of free flow at the floor of the burr chamber or exit chute will confuse any attempt to make sense of grind adjustment. There's a quick and dirty, if incomplete, alternative that would be a good diagnostic: take a very thin, flexible piece of plastic tubing, like a disposable espresso stirrer or a plastic ball point pen cartridge tube, and poke it up the chute from below, being sure to angle left, then right, as it enters the lower burr chamber. This will clear the chute and most of the burr chamber under the spinning burr. Despite the grinder seeing little use, if the buildup under there is really old, the coffee oils may have congealed to cement the stale grounds into a hard plaque. After you've loosened some crud, pulse the grinder and repeat, until you can see a clear chute and empty space under that lower burr.

GeorgeP922 wrote:I also must say, that I still don't get the "lots and lots of turn on stepless" crowd. I feel that maybe 3 full 360 turns is the range from lawn mulcher to zero point.

I think you're confusing turns of the butterfly-handle screw (which is what stepless users do) with turns of the burr collar (which is what stepped users do, directly).