JohnB. wrote:If you were to hit the top of the rotor shaft hard enough you could damage the carrier &/or the lower bearing.

This is exactly what I'm afraid of doing. Thanks for the heads up John. I'm beginning to think this might not be worth the effort.

JohnB. wrote:FYI - On my 2006 Super Jolly which has never had the burr carrier removed there is a 5mm gap between the burr chamber floor & the bottom of the burr carrier.

It certainly looks like this height is normal, especially according to the pics/replies in this thread. Why, then, did my zero-point change so drastically?

It would only take a very small change in the burr holder height to account for the difference in your zero point. I'd still try to make sure the burr holder is fully seated &/or that the rotor assy hasn't pulled up slightly, just do it very carefully.

I will try, and try carefully indeed. Thanks again for all your helpful insight, John.

Just for clarification, how exactly could the rotor assembly have pulled up? I thought things were pretty tight in there...although I do distinctly remember tightening down the 3 long screws to get the lower carrier out and hearing a couple popping noises . I thought it was just the sound of the carrier dislodging from the shaft. Not to mention the sheet metal plate underneath that carrier got a little bent up in the process. I guess that 3-screw method does have its drawbacks

Most likely the popping noises where caused by the tight fit of the carrier on the shaft. How did you reseat the carrier when you reinstalled it?

It certainly looks like this height is normal, especially according to the pics/replies in this thread. Why, then, did my zero-point change so drastically?

I would think it could be a combination of things. You may not have the carrier seated as far as before, the original burrs were really worn, (new springs?). I can't really explain it but would think that if it is grinding correctly what difference does the # make?

To reseat the carrier I placed it on the shaft carefully, minding the pin alignment, then lowered it down and pressed with my hands as far as I could go. I then reapplied the center bolt, assuming that it would take care of seating it the rest of the way. There seems to be a little shoulder right below the pin that the carrier rests on...when the bolt is tightened, it can go no further, and should be set properly, right?

I was looking at it again last night....that adjustment collar is clearly higher than before. Lots of thread is visible, and the adjustment itself seems just a bit too easy to make.

You can't see the roll pin so you don't know if it is fully seated or not. Considering how tight it was coming off the shaft heating the carrier before installation & tapping it down with a wooden block or pipe between it & the hammer would have been a good idea. I would remove the lower burr & center bolt, heat the burr carrier with a hair dryer set to hot or heat gun & then make sure it is fully seated by giving it a good solid tap or two. Then reassemble & see if your zero point has returned. If not consider buying a new decal for the adjustment ring & don't remove the burr carrier in the future unless you need to change the upper bearing.

Last night I tried a few of these things out, with some limited success. Sorry in advance for the long post!

First of all, what a great suggestion it was to heat the carrier/rotor shaft with a hair dryer. For anyone looking to remove this part on your Mazzer, I highly recommend this method! It made the removal process much easier. The 3-screw method now required much less force, and after just a few turns the carrier slid right out.

Once I had everything removed, I was able to compare the carrier-less shaft with pics from this thread...Help with Mazzer Super Jolly Disassembly, and mine looked strikingly similar. Notice the shoulder is indeed sitting well above the sheet metal bearing cover.

After another thorough cleaning, I gently positioned the carrier back on the shaft, again minding the pin, and shined a flashlight into the chute as i heated everything back up with the hair dryer. Again, it was so easy after heating that I could seat the carrier entirely with my bare hands. Looking through the chute, I was sure the positioning was spot on (in fact, I tried it once intentionally missing the roll pin so I could see the difference...it's a very obvious one, btw), and I was able to hear an audible "click" as it came to rest on the shoulder. I then replaced the center bolt, and was certain this thing was now properly seated.

JohnB. wrote:Another option would be to slip a piece of pipe over the shaft and tap on that so you would be hitting the flat burr carrier instead of the shaft. Since the burr carrier sits on a roll pin in the rotor shaft this would reseat the shaft to the correct position if it has indeed moved up without risking damage to the shaft.

Before reassembling everything, I wanted to try this, so I placed a 3/4" x 2 1/4" rubber washer on the carrier, and using a small block of oak on top of a 2" piece of steel pipe, I gave it a couple solid hits with my hammer. I had the bottom cover removed so I could see if anything was moving that otherwise shouldn't be, and all seemed fine. However, this really didn't seem to be doing much. Not wanting to overdo it, I stopped and put everything back together to test the grinder.

The zero point is now about 7 notches lower, so evidently the re-seating/tapping combo did help a bit. The collar still isn't quite where it was before, and could come around another 150 degrees or so. Nevertheless, the grinder does seem to be working fine, so I just may leave it. Unless of course anyone else has other suggestions

-Mike

I'm just surprised at all of the proponents of hammers to work on grinders. They are precision made, and have a lot of soft brass parts. Other parts, such as motor housing end caps, are made of cast aluminum, which is brittle. I'd be worried about cracking and bending parts on a machine which is designed for precision grinding.

If you hit it with a hammer, how do you know how hard to hit it without causing damage?

I prefer to use PB Blaster to loosen parts. I've worked on a lot of grinders - some in poor pretty condition - and never had to use a hammer.

Bearings and Hammers don't mix, ever

See Warning about grinder burr / carrier removal