John: that looks pretty darn good to me. Try doing that in sketchup..... or better yet, I wonder if it could be imported?

Mark

Hi guys,

I agree that the sarm support for the upper bearing will be enough and cheaper than making a whole plate, so I will go with that. I'm still sticking to the rod idea, but I think I will add springs to push the carrier up (or down depends) and eliminate any thread play.

I'm also pretty sure I will use Robur single phase 71mm burrs, I can get them here pretty cheap and I think they will work well. I was thinking about Kony burrs but it's harder to find them in the UK, so that's the main reason I'm sticking with Roburs.

Regards,
dsc.

Dsc, it seems logical to me that the springs press against the adjuster, and that the force from the grinder to spread the burrs not be counteracted by the spring but by the more static adjuster. In my design, as well as yours, that would mean the springs should push the carriage up against the adjuster just as the grinding motion pushes up against the adjuster. Just my opinion.

Sweet skilz in autocad John! If I were to try and do that in Sketchup, it'd probably be best done with Ruby as a plugin rather than using the built in tools. Mark we should be able to import it into Sketchup with a .3ds file. John, were you working off any theory in deciding the basic shape? Or was it more freehand?

edgar

were you working off any theory in deciding the basic shape? Or was it more freehand?

To be honest, just playing around, although I did want to see what it would look like with a bit more aggressive cut in the top star.

Jepy,

Wow, great model. AutoDesk Inventor must be really easy to use. I have not used Pro E for a quite a few years but I think using it for that model would take several hours at least.

Geoffrey!

arriflex wrote:I like the idea of supporting the large upper pulley on both sides, and agree with the notion that belt replacement is a rare occurrence. It may simply be aesthetic, but one could support the bearing above the pulley from between the two pulleys and not have added complexity to belt changes since most of the force is aimed at the motor pulley...

edgar

I like the idea but instead of an L shape for the support a smaller A frame support would work better.

And here is yet another way to adjust the vertical location linearly of the chassis that carries the outer burr. Now things are getting unnecessarily complicated to my mind. However, it's fun to consider. Here I've driven the posts (which would have to be embedded in bearings on the top and bottom plates) with a worm screw from the side. An advantage to this is that the posts that drive the vertical movement also handle the structural support for the carriage. I don't have the calcs in my head for what the reductions come out to, but I imagine it's decently reduced. Backlash is an issue, but not to hard to deal with. The worm drive too would need to bearings on the ends and plenty of lateral thrust to engage it in the pulleys.

Ahh, the holidays. Where I spend more time thinking of the things I want to do than actually doing any of them!

edgar

Hi guys,

I'm curious if anyone thought of a vertical configuration, something similar to a Mahlkonig Gautemala:

http://www.flickr.com/photos/tompjagiello/3724659436/

http://www.flickr.com/photos/tompjagiello/3730897130/

http://www.flickr.com/photos/tompjagiello/3723851783/

?

Regards,
dsc.

My only concern for what I would actually consider a horizontal configuration as in the Mahlkonig is the efficacy of feeding the beans into a conic burr. It just doesn't feel right to me to orient the bean entrance to a cone 90 degrees off gravity! With the flat burr set, perhaps this is less of an issue; although I would still be inclined to assume that the burr will not be loaded evenly.

edgar

I have been enjoying this thread despite not having the necessary grey matter to fully understand it much of it. I am always amazed at how technically competent some people are!

Having said that can you tell me if a well engineered hand grinder using those big 71 burrs is feasible?

I myself (and likely others) would be happy to forego the extra expense of motors, electronics and greater build complexity etc. if all that that was going to give us was 1/50th (or what ever) the speed to a completed perfect espresso dose. (Apparently a quality pre-war German hand mill can do it in 75-100 revolutions).

Or would you need Ahnold's bulging arms to manually grind 71mm burrs?
Cheers, Ted.