Unfortunately I don't have the tools to machine a new aligned pulley, I doubt it could be mounted wrong as I doubt it had ever been opened before now. Looks like I won't be having this aligned for a while, might be due to the plastic grinding chamber and baratza won't ship any to Canada until they release their own guide on how to install said chamber which Covid-19 has delayed for at least a month.

Though I guess it could also be due to the motor pulley, the marker is not being rubbed off closer to the rear of the machine which could indicate that the belt is too tight, unfortunately even applying some pressure while tightening the belt doesn't result in a very loose belt.

My solution to this is to put a sleeve on the shaft, turn it true and then open up the bore of the pulley to fit the sleeve. This results in a perfectly true spinning pulley.

--Jake, from his earlier post:

Hi Jake,

I understand the remedy for a wobbling drive pulley idea you described earlier, but have a couple of questions:

Is the sleeve aluminum, or steel? It appears to be metal, from the photo. How do you secure that sleeve to the shaft first? And how did you "turn it true"? A lathe? Abrasive paper/sandpaper?

I'm sure the answers are rudimentary to an engineer. Thanks for your patience!

Thanks again!

Patrick

Hey Patrick,

The sleeve is steel. It was "shrunk" onto the motor shaft, which means it was bored slightly smaller than the "diameter" of the twisted gear shaft on the motor. It was then heated, which opens up the bore, and pressed onto the shaft. When it cooled down, it is then "one" with the shaft.

My friend with a lathe then chucked the entire motor in a large lathe and spun the shaft up with a battery, using the lathe tools to turn down the outer diameter down to a nominal size (I this we settled on 5/16" up from .230"). This gets you a cylinder that turns true with the motor bearings and is slightly larger than the wobbly shaft.

The final step was to carefully mount the motor pulley in the lathe and open the bore to fit the 5/16" shaft and then secure everything together with the set screw.

Cheers!

- Jake

Jake,

Thanks for spelling that out so clearly. I misunderstood: it's likely the motor shaft itself wobbling. I'd assumed it was something to do with the pulley--i.e. that there must be some play between its interior diameter and that of the shaft, such that tightening the set screw in the grooved shaft moved things out of true.

I'm not sure I'll be able to find a willing lathe operator, especially given current restrictions on movement, etc. So this elective surgery will have to be postponed. It's a fun and harmless distraction though, in these difficult days, to think about making progress on this mechanical problem.

Good luck to you (and all).

Patrick

It's less that the shaft is not true and more that it isn't a shaft. It is a helical cut gear with an absurdly shallow helix angle. If the pulley had a helix cut in it and twisted down onto the shaft, all would likely be well. But instead you have a round bore seated onto a twisted 5 point "star" that is locked in place with a single set screw. It's just not a good solution.

The only way I found to get the pulley seated true was to turn the gear into a shaft, hence all the aforementioned shrinking and turning and such

I suspect that if you are setting your belt tension on the looser side, the pulley isn't causing major harm, but I had a means to correct it, and it bothered me. So I fixed it.

Cheers!

-Jake

My "super aligned" vario is working better than ever. There was a bit of a period where I actually had to re-break in the burrs, I'm guessing because I was finally getting full surface contact with the beans, but now my fines are extremely minimal and my brews have never been clearer or crisper. I still get a decent amount of micro-fines, but I've stopped sifting those out and have actually noticed a very slight increase in complexity of flavor.

Very happy with things.

This is amazing. Thx to Jake and all for the method and discussion. Hoping to get some guidance on a couple of points:

1) Fixing a side wear pattern after numerous attempts performing the procedure on my Forte: I understand that to correct the side wear pattern (marker worn off to the right), I need to move the grind chamber to the right. Do I do this by loosening the 2 screws attaching the plate to the motor and rotating the motor along the left motor plate screw or is this done exclusively by just pushing the lower burr carrier with the grind chamber loosened and thus the grind chamber to the right (or left when upside down)? Does the belt (via those 2 motor plate screws) need to be loosened to rectify the side wear pattern?

2) I noted the instruction to press gently on the motor to tighten the belt when tightening the motor plate screws...hoping to get a bit of clarity on what is meant by this.

Thank you!

Steveberco wrote:1) Fixing a side wear pattern after numerous attempts performing the procedure on my Forte: I understand that to correct the side wear pattern (marker worn off to the right), I need to move the grind chamber to the right. Do I do this by loosening the 2 screws attaching the plate to the motor and rotating the motor along the left motor plate screw or is this done exclusively by just pushing the lower burr carrier with the grind chamber loosened and thus the grind chamber to the right (or left when upside down)? Does the belt (via those 2 motor plate screws) need to be loosened to rectify the side wear pattern?

Side wear pattern is fixed exclusively by pushing the grind chamber with the screws loosened. The belt pulls straight back, so it should not need to be loosened to correct for side wear. I recommend the following:

1. Loosen the grind chamber screws until the grind chamber can be shifted freely.
2. Bring the burrs into contact using the lever(s)/calibration screw(s) as needed such that the burrs rub against each other and the motor pulley can still be turned by hand.
3. Wiggle the grind chamber all the way left, all the way right and then back to center.
4. Set the macro lever one notch coarser and then bring it back where it was and check the burr rub.
5. Repeat step 3
6. Repeat step 2.
7. Tighten grind chamber screws a little bit (quarter turn or so).
8. Repeat steps 4 through 7 until grind chamber screws are fully tightened.

2) I noted the instruction to press gently on the motor to tighten the belt when tightening the motor plate screws...hoping to get a bit of clarity on what is meant by this.

I simply mean that I gently apply pressure on the motor, pressing it away from the grind chamber, while I snug up the two motor mounting bolts. Nothing fancy here.

Thank you!

You're very welcome.

Cheers!

- Jake

Very helpful, thank you!
I often end up with a diagonal type pattern in which most of the wear is, say, to the left, but a portion is also on the front/bottom of the burr. Is it best to handle the horizontal and vertical misalignment in separate iterations or rather loosen up the belt too and try in more of a random attempt to let everything settle? THX!!!